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Rhizoctonia Brown Patch Introduction
New Hampshire, University of
Rhizoctonia Brown Patch Turf Pest Fact Sheet 44 Introduction Rhizoctonia brown patch is a common in diameter. Description On close-cut grass, such as golf greens, Rhizoctonia brown patch appears as light of Rhizoctonia brown patch appears during periods of warm, humid weather, when dark, purplish "smoke rings" 1
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia web blight, caused by several Rhizoctonia spp., is an important disease of evergreen azaleas and other ornamental plants in nurseries. The primary pathogens causing web blight are binucleate Rhizoctonia anastomosis groups (AG) (= Ceratobasidium D.P. Rogers, teleomorph). In southern AL an...
Pathologie vgtale Maladies des plantes dues Rhizoctonia
Paris-Sud XI, Université de
Pathologie végétale Maladies des plantes dues ŕ Rhizoctonia solani (Kühn) : stratégie et techniques; Plant diseases induced by Rhizoctonia solani (Kuhn) : strategy and methods of study. Results profession agricole demandant de résoudre des problčmes posés par Rhizoctonia solani ont notablement augmenté
Rhizoctonia web blight on azalea
Technology Transfer Automated Retrieval System (TEKTRAN)
Currently, fungicides are the only useful control for azalea web blight, but fungicides do not eliminate the pathogen. We have discovered that Rhizoctonia colonizes the entire azalea plant 12 months of the year in the Gulf Coast climate. This results in healthy appearing stems collected for propagat...
Plant Disease Lesson: Rhizoctonia Diseases of Turfgrass
NSDL National Science Digital Library
Lane P. Tredway (University of Georgia, Athens; )
This plant disease lesson on Rhizoctonia diseases of turfgrass (caused by the fungi Rhizoctonia species) includes information on symptoms and signs, pathogen biology, disease cycle and epidemiology, disease management, and the significance of the disease. Selected references are listed and a glossary is also available for use with this resource.
Rhizoctonia seedling disease on sugar beet
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia seedling damping-off can cause losses in sugar beet as well as providing inoculum for later root rot. The disease is caused by Rhizoctonia solani. The pathogen has several subgroups, anastomosis groups (AG), of which AG-4 has historically been associated with damping-off, while AG-2-2 is...
Epidemiology / pidmiologie Spatial distribution of Rhizoctonia oryzae and
Zhang, Hao
Epidemiology / Épidémiologie Spatial distribution of Rhizoctonia oryzae and rhizoctonia root rot in direct-seeded cereals T.C. Paulitz, H. Zhang, and R.J. Cook Abstract: Rhizoctonia oryzae causes root rot Rhizoctonia oryzae cause le rhizoctone noir et l'arręt de croissance chez le blé, l'orge et d'autres petites
Rhizoctonia root rot of lentil caused by Rhizoctonia solani AG 2-1
Technology Transfer Automated Retrieval System (TEKTRAN)
Lentil root rot symptoms were observed in commercial fields in the US Pacific Northwest during the unusually cool and moist spring weather of 2010. Symptoms included sunken lesions on root and stem with brown discoloration, resembling diseases caused by Rhizoctonia solani. Rhizoctonia solani was i...
Research on Rhizoctonia Web Blight on Azalea
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 'Gumpo' azalea plants. Plant ...
Obtention de la forme sexue de Rhizoctonia solani Khn : Thanatephorus cucumeris
Paris-Sud XI, Université de
NOTE Obtention de la forme sexuée de Rhizoctonia solani Kühn : Thanatephorus cucumeris (Frank) Donk Rhizoctonia solani (Thanatephorus cucumeris) au moyen de deux techniques différentes. SUMMARY Production of basidia in Thanatephorus cucumeris (Frank) Donk (anamorph Rhizoctonia solani Kiihn). The purpose
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia solani is a soilborne fungal plant pathogen responsible for economic losses of crops worldwide. Isolates of Rhizoctonia (anastomosis group 3) cause a disease commonly known as black scurf, stem and stolon canker of potato. We observed that some isolates of the pathogen lose their ability...
Seasonal presence of Rhizoctonia species in container-grown azalea
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia web blight has been observed to be regularly distributed across large nursies and randomly distributed in blocks of azalea cultivars of varying susceptibility. The main objective of this project was to determine seasonal changes in the population of binucleate Rhizoctonia species in indi...
Suppression of Rhizoctonia solani in potato fields. 1. Occurrence
G. Jager; H. Velvis
A search was made forRhizoctonia solani-suppressive soils by establishing many small experimental plots, half of which were planted withRhizoctonia-infected seed potatoes and the other half with disinfected seed stock. The sclerotium index of the harvested tubers was compared witht that of the seed potatoes. In suppressive soils, the sclerotium index of the harvest is much lower than that of the
Cohen, Michael F.
SUPPRESSION OF RHIZOCTONIA ROOT ROT BY STREPTOMYCES IN BRASSICA SEED MEAL-AMENDED SOIL Mark Mazzola that the suppression of certain apple root pathogens and parasites, including Rhizoctonia solani and Pratylenchus
Optimum Timing of Pre-Plant Applications of Glyphosate to Manage Rhizoctonia Root Rot in Barley
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia root rot, caused by Rhizoctonia solani AG-8 and R. oryzae, is considered one of the main deterrents for farmers to adopt reduced tillage systems in the Pacific Northwest. Because of the wide host range of Rhizoctonia spp., herbicide application before planting to control weeds and volunt...
Rle de Rhizoctonia solani Khn dans la manifestation de certains symptmes de verse parasitaire du mas
Paris-Sud XI, Université de
Rôle de Rhizoctonia solani Kühn dans la manifestation de certains symptômes de verse parasitaire du, on constate la présence trčs fréquente de Rhizoctonia solani. Des essais d'inoculation au champ ŕ différentes Importance of Rhizoctonia solani Kfhn in some lodging symptoms on maize. In Western France (Vendee area
Mukhtar, Saqib
THE PERFORMANCE OF BREEDING LINES WITH PARTIAL RESISTANCE TO PYTHIUM ULTIMUM AND RHIZOCTONIA SOLANI was included in the test, without chemical protection against P. ultimum and Rhizoctonia solani varieties grown in the U.S. are highly susceptible to seedling diseases caused by Rhizoctonia solani (Figure
High Levels of Gene Flow and Heterozygote Excess Characterize Rhizoctonia solani AG-1 IA
McDonald, Bruce
High Levels of Gene Flow and Heterozygote Excess Characterize Rhizoctonia solani AG-1 IA levels of gene flow and heterozygote excess characterize Rhizoctonia solani AG-1 IA (Thanatephorus of the basidiomycete Thanatephorus cu- cumeris (anamorph Rhizoctonia solani) remains un- known. Here, we present
Evolution du complexe parasitaire constitu par Rhizoctonia cerealis Van der Hoeven et Pseudo-
Paris-Sud XI, Université de
Evolution du complexe parasitaire constitué par Rhizoctonia cerealis Van der Hoeven et Pseudo causé par Rhizoctonia cerealis semble aujourd'hui prendre de l'extension. Des expérimentations sur blé composed of Rhizoctonia cerealis Van der Hoeven and Pseudocercosporella herpotrichoides (Fron) Deighton
Antagonisme in vitro de Trichoderma spp. vis--vis de Rhizoctonia solani Khn
Paris-Sud XI, Université de
Antagonisme in vitro de Trichoderma spp. vis-ŕ- vis de Rhizoctonia solani Kühn Pierre CAMPOROTA LN sélection de souches de Trichoderma spp. utilisables pour la lutte biologique contre Rhizoctonia solani dans. SUMMARY In vitro antagonism between Trichoderma spp. and Rhizoctonia solani We present here results
Mesure de la colonisation saprophytique en comptition de Rhizoctonia solani Khn
Paris-Sud XI, Université de
Mesure de la colonisation saprophytique en compétition de Rhizoctonia solani Kühn dans les sols et piégeage de Rhizoctonia solani Kühn a été mise au point afin de pouvoir estimer son aptitude ŕ la colonisés par le Rhizoctonia solani. La méthode est quantifiée en faisant varier la concentration de terre ŕ
Diversity and host specificity of endophytic Rhizoctonia-like fungi from tropical orchids
J. Tupac Otero; JAMES D. ACKERMAN; PAUL BAYMAN
All orchids have an obligate relationship with mycorrhizal symbionts. Most orchid mycorrhizal fungi are classified in the form- genus Rhizoctonia. This group includes anamorphs of Tulasnella, Ceratobasidium, and Thanatephorus. Rhizoctonia can be classified according to the number of nuclei in young cells (multi-, bi-, and uninucleate). From nine Puerto Rican orchids we isolated 108 Rhizoctonia-like fungi. Our isolates were either
Rhizoctonia cerealis Van der Hoeven, agent du rhizoc-tone des crales en France. Caractristiques et variabi-
Paris-Sud XI, Université de
Rhizoctonia cerealis Van der Hoeven, agent du rhizoc- tone des céréales en France. Caractéristiques. S'ils appartiennent bien au genre Rhizoctonia, ils se différencient de R. solani par leur vitesse de additionnels : Souches, agressivité, Rhizoctonia solani, blé, orge, variétés. SUMMARY Rhizoctonia cerealis Van
Biogenesis of pipecolic acid in Rhizoctonia leguminicola
Wickwire, B.M.
This laboratory has long been interested in the biogenesis and biological properties of two indolizidine alkaloids, slaframine and swainsonine that are produced by the fungal parasite Rhizoctonia Leguminicola. Slaframine, (1S,6S,8aS-1 acetoxy-6-aminooctahydroindolizine) is a parasympathetic secretagogue, and swainsonine (1S,2R,8R,8aR-1,2,8-trihydroxyoctahydroindolizine) is a potent {alpha}-mannosidase inhibitor. This thesis concerns the initial steps of the biosynthesis of these alkaloids from lysine, via the common intermediate pipecolic acid, in whole cells and cell free enzyme systems of R. leguminicola. In confirmation of earlier work performed in this laboratory, L-lysine was used preferentially for pipecolate biosynthesis in R. Leguminicola. This pathway was supported by the finding that cell free extracts of R. leguminicola consistently converted L-(U-{sup 14}C)-lysine to three labelled metabolites: saccharopine, peak II, and pipecolic acid. Peak II was subsequently identified by appropriate proton NMR studies to be {delta}{sup 1}-piperideine-6-carboxylate, and the following pathway of pipecolic acid formation was postulated: L-lysine {yields} saccharopine {yields} {delta}{sup 1}-piperideine-6-carboxylate {yields} pipecolate. This pathway was confirmed by demonstration of each enzymatic step in vitro from purified radiolabeled substrates.
Influence of glyphosate on Rhizoctonia crown and root rot (Rhizoctonia solani) in glyphosate-resistant sugarbeet (Beta vulgaris L.)
Technology Transfer Automated Retrieval System (TEKTRAN)
Previous greenhouse studies with a non-commercial glyphosate-resistant sugarbeet variety indicated that susceptibility to Rhizoctonia crown and root rot could increase after glyphosate was applied. Greenhouse and field experiments were conducted in 2008 and 2009 to determine if glyphosate influenced...
Molecular diversity of binucleate Rhizoctonia AGA in China
Y. Q. Li; L. P. Lei; W. H. Dong; S. M. Wang; S. Naito; G. H. Yang
AG-A belongs to the binucleate Rhizoctonia (BNR) anastomosis group (AG) of the Ceratobasidium teleomorph, which parasitizes the roots of many plant species. Ninety nine isolate species of AG-A were obtained from Tibet,\\u000a Sichuan, and Yunnan Province in China. All isolates were divided into three types based on their cultural characteristics.\\u000a Type I: abundant aerial mycelia, dense hyphae, loose sclerotia; Type
Production of iturin A by Bacillus amyloliquefaciens suppressing Rhizoctonia solani
G. Y Yu; J. B Sinclair; G. L Hartman; B. L Bertagnolli
Bacillus amyloliquefaciens strain B94 was used as a biocontrol agent to suppress Rhizoctonia solani and other fungal plant pathogens. Three major antifungal compounds were purified from its culture broth, each has an amino acid composition consisting of Asn, Gln, Ser, Pro, and Tyr in a molar ratio of 3:1:1:1:1. Fast atom bombardment mass spectrometry\\/mass spectrometry (FAB MS\\/MS) collision induced dissociation
Mutations of Fusarium oxysporum and Rhizoctonia solani by TCMTB
A. Vanachter; E. van Wambeke
Upon screening several fungicides, a few Fusarium oxysporum isolates and one Rhizoctonia solani isolate showed a distinct\\u000a and sudden decrease in sensitivity to TCMTB (2-(thiocyanomethylthio)-benzothiazole). The screening was carried out in Petri\\u000a dishes using an agar medium, mixed with the test fungicides, in the center of which a mycelial piece of the test fungus was\\u000a placed. In several TCMTB-containing plates,
Population structure of the rice sheath blight pathogen Rhizoctonia solani AG-1 IA Celeste C. Linde1,3
McDonald, Bruce
Population structure of the rice sheath blight pathogen Rhizoctonia solani AG-1 IA from India of Rhizoctonia solani AG-1 IA causing rice sheath blight from India was eval- uated for 96 isolates using seven Rhizoctonia sp. The population structure of the remaining 77 R. solani AG-1 IA Indian isolates was similar
Pectolytic enzymes produced by Rhizoctonia bataticola in culture and Rhizoctonia -infected tissues of potato tubers ( Solanum tuberosum L.)
A. C. Amadioha; A. O. Oladiran
Rhizoctonia bataticola produced both polygalcturonase (PG) and pectin-methyl-esterase (PME) in vitro and in vivo, the former releasing more reducing materials in reaction mixtures. Extracts of healthy tissues ofSolanum tuberosum contained PME but no PG. Salt extraction of healthy and diseased tissues increased the amount of PME obtained. The activity of PME produced in vivo increased after dialysis and addition of
Preparation on Inoculum of Rhizoctonia solani Kuhn for an Artificially Inoculated Field Trial
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia crown root and rot, caused by Rhizoctonia solani Kühn, is a serious disease resulting in substantial economic losses in sugar beet production worldwide. A consistent, uniform disease pressure of the correct intensity is necessary to effectively screen sugar beet for resistance to Rhizoc...
Pathogenicity of three isolates of Rhizoctonia sp. from wheat and peanut on hard red winter wheat
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia-induced root diseases can significantly affect wheat and peanut production where these two field crops are grown in rotation. Hence, this study characterized two isolates of Rhizoctonia spp. from wheat [R. cerealis (RC) and R. solani (RSW)] and one from peanut [R. solani (RSP) ] for cul...
Rhizoctonia web blight development on container-grown azalea in relation to time and environmental factors
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia web blight, caused by binucleate Rhizoctonia spp., is an annual problem in the southern United States on container-grown azaleas (Rhododendron spp.) that receive daily irrigation. Disease progress was assessed weekly from mid-May to mid-September in blocks of nursery-grown plants at thre...
Rhizoctonia root rot resistance in experimental sugar beet cultivars in Twin Falls County, ID, 2012
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia root rot continues to be a concerning problem in sugar beet production areas. To investigate resistance to this disease in 26 experimental sugar beet cultivars, field studies were conducted with three Rhizoctonia solani AG-2-2 IIIB strains. Based on means for the 26 cultivars, surface ...
Selection for resistance to the rhizoctonia-bacterial root rot complex in sugar beet
Technology Transfer Automated Retrieval System (TEKTRAN)
The Rhizoctonia-bacterial root rot complex continues to be a concerning problem in sugar beet production areas. To investigate resistance to this complex in 26 commercial sugar beet cultivars, field studies and greenhouse studies with mature roots from the field were conducted with Rhizoctonia solan...
Influence of sugarbeet tillage Systems on the rhizoctonia-bacterial root rot complex
Technology Transfer Automated Retrieval System (TEKTRAN)
The Rhizoctonia-bacterial root rot complex in sugarbeet caused by Rhizoctonia solani and Leuconostoc mesenteroides can cause significant yield losses. To investigate the impact of different tillage systems on this complex, field studies were conducted from 2009 to 2011. Split blocks with conventio...
Interaction of Rhizoctonia solani and Rhizopus stolonifer Causing Root Rot of Sugar Beet
Technology Transfer Automated Retrieval System (TEKTRAN)
In recent years, growers in Michigan and other sugar beet production areas of the United States have reported increasing incidence of root rot with little or no crown or foliar symptoms in sugar beet with Rhizoctonia crown and root rot. In addition, Rhizoctonia-resistant beets have been reported wit...
Rhizoctonia Species Associated With Bark Media and Plant Strata of Container-Grown Azalea
Technology Transfer Automated Retrieval System (TEKTRAN)
Symptoms of Rhizoctonia web blight, caused predominantly by binucleate Rhizoctonia (BNR) anastomosis group U, develops annually from late-June to mid-September on container-grown azaleas (Rhododendron spp.) in the southern United States. In 2005 and 2006, 'Gumpo White' azalea plants with a disease ...
Preparation of Inoculum of Rhizoctonia solani Kuhn for an Artificially Inoculated Field Trail
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia crown root and rot, caused by Rhizoctonia solani Kühn, is a serious disease resulting in substantial economic losses in sugar beet production worldwide. A consistent, uniform disease pressure of the correct intensity is necessary to effectively screen sugar beet for resistance to Rhizoc...
Characterization of Rhizoctonia isolates associated with damping-off and crown rot of rooibos seedlings
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia species were reported to be an important component of the complex involved in damping-off of rooibos (Aspalathus linearis) seedlings and cause severe crown rot of seedlings in nurseries. However, no information is available on the anastomosis groups (AGs) of Rhizoctonia associated with d...
Risk of Rhizoctonia Web Blight Development on Container-Grown Azalea
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia web blight, caused by binucleate Rhizoctonia spp., is an annual problem in the southern United States on container-grown azaleas (Rhododendron spp.) that receive daily irrigation. Disease progress was assessed weekly from mid-May to early October in blocks of nursery-grown plants at four...
Chemical and Hot Water Treatments to Eliminate Rhizoctonia From Azalea Stem Cuttings: Failures and Successes
Technology Transfer Automated Retrieval System (TEKTRAN)
Azalea web blight is an annual problem on some evergreen azalea cultivars grown in containerized nursery production in the southern and eastern United States. The binucleate Rhizoctonia species, which cause the disease, are spread on new shoot growth harvested for propagation. Rhizoctonia can be eli...
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia solani, a ubiquitous soilborne fungal plant pathogen, is responsible for economic losses of agricultural, forestry, horticultural and ornamental crops worldwide. Soil actinomycetes are known to enhance fertility and possess antimicrobial properties against various plant pathogens. One hu...
A version of this article appeared in GreenMaster 41(3):28-30 (June 2006) A New Rhizoctonia Fungus on Turfgrass in Ontario
Hsiang, Tom
A version of this article appeared in GreenMaster 41(3):28-30 (June 2006) A New Rhizoctonia Fungus on Turfgrass in Ontario By Tom Hsiang, Darcy Olds and Russ Gowan The fungal genus Rhizoctonia contains many include brown patch caused by R. solani and yellow patch caused by R. cerealis. Other Rhizoctonia species
Summa Phytopathol., Botucatu, v. 32, n. 3, p. 247-254, 2006 247 Incompatibilidade somtica em Rhizoctonia solani AG-1 IA da soja
McDonald, Bruce
Rhizoctonia solani AG-1 IA da soja Ana Paula da Silva de Campos1 e Paulo Cezar Ceresini1, 2 1 Faculdade de/03/2006. ABSTRACT Rhizoctonia solani anastomosis group 1 IA (AG-1 IA) is considered one of the most important structure. RESUMO O fungo Rhizoctonia solani AG-1 IA é um dos patógenos mais importantes que afeta a cultura
Pathogenicity, characterization and comparative virulence of Rhizoctonia spp. from insect-galled roots of Lepidium draba in Europe
A. J. Caesar; TheCan Caesar; Marloes H. Maathuis
The association of Rhizoctonia spp. with insect-damaged and diseased tissue of the invasive perennial Lepidium draba was documented throughout the range of L. draba that was surveyed in Europe, including Hungary, Austria, Switzerland and France. Samples that could be both maintained under cooled conditions after collection and promptly processed consistently yielded Rhizoctonia solani, 11 isolates of which anastomosed with AG-4,
Technology Transfer Automated Retrieval System (TEKTRAN)
EL53 sugarbeet germplasm is substantially derived from previously released smooth-rooted, low soil tare germplasm releases with two additional cycles of selection for freedom from Rhizoctonia crown and root rot disease. Previous low soil tare releases have been uniformly susceptible to Rhizoctonia ...
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia solani and R. oryzae are the principal causal agents of Rhizoctonia root rot, damping-off and bare patch in dryland cereal production systems of the Pacific Northwest. We developed SYBR Green I-based real-time quantitative PCR (Q-PCR) assays that specifically amplified the internal trans...
Rhizoctonia anastomosis groups associated with diseased rooibos seedlings and the potential of compost as soil amendment for disease suppression
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia spp. associated with rooibos in the Western Cape province of South Africa were recovered during the 2008 season by planting seedlings in rhizosphere soils collected from 14 rooibos nurseries. Seventy five Rhizoctonia isolates were obtained and 67 were multinucleate and 8 binucleate Rhiz...
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia web blight on containerized azalea is an annual problem during the summer months in the southern U.S. Rhizoctonia spp. were isolated from symptomatic leaf tissue from two nurseries in Mississippi and Alabama during June, July and August of 2002, 2003, and 2004. The internal transcribed s...
Real-time PCR assay for detection of Rhizoctonia sp. in insect galled roots of Lepidium draba sp draba
Technology Transfer Automated Retrieval System (TEKTRAN)
The association of necrotrophic soil-borne pathogens, Rhizoctonia spp., with a root-attacking weevil, Ceutorhynchus assimilis, and diseased tissues of Lepidium draba, an invasive perennial weed in the U.S., has been documented in its Eurasian native range. Among all isolates of Rhizoctonia solani an...
First evidence of a binucleate Rhizoctonia as the causal agent of dry rot canker of sugar beet in Nebraska, USA
Technology Transfer Automated Retrieval System (TEKTRAN)
Sugar beet (Beta vulgaris L.) is the primary source of domestic sucrose in the United States. In 2011, a sugar beet field in Morrill County NE was noted with wilting and yellowing symptoms suggestive of Rhizoctonia root and crown rot (RCRR), an important disease of sugar beet caused by Rhizoctonia s...
A Search for the Phylogenetic Relationship of the Ascomycete Rhizoctonia leguminicola Using Genetic Analysis.
Alhawatema, Mohammad S; Sanogo, Soum; Baucom, Deana L; Creamer, Rebecca
Rhizoctonia leguminicola, which causes fungal blackpatch disease of legumes and other plants, produces slaframine and swainsonine that are largely responsible for causing salivation, lacrimation, frequent urination, and diarrhea in grazing animals including cattle, sheep, and horses. The original identification of R. leguminicola was based only on morphological characters of the fungal mycelia in cultures because of the lack of fungal genetic markers. Recent investigations suggested that R. leguminicola does not belong to genus Rhizoctonia and is instead a member of the ascomycetes, necessitating an accurate reclassification. The objective of this study was to use both genetic and morphological characters of R. leguminicola to find taxonomic placement of this pathogen within ascomycetes. Internal transcribed spacer region (ITS) and glyceraldehyde-3-phosphate dehydrogenase (gpd) encoding gene were amplified from R. leguminicola isolates by PCR using universal primers and sequencing. Rhizoctonia leguminicola ITS and gpd sequences were aligned with other fungal sequences of close relatives, and phylogenetic trees were constructed using neighbor-joining and parsimony analyses. Rhizoctonia leguminicola isolates were clustered within a clade that contains several genera of ascomycetes belonging to the class dothideomycetes. We suggest that the fungus is misidentified in the genus Rhizoctonia and propose its reclassification in a new genus within the phylum Ascomycota. PMID:25585493
Molecular and genetic aspects of controlling the soilborne necrotrophic pathogens Rhizoctonia and Pythium.
Okubara, Patricia A; Dickman, Martin B; Blechl, Ann E
The soilborne necrotrophic pathogens Rhizoctonia and Pythium infect a wide range of crops in the US and worldwide. These pathogens pose challenges to growers because the diseases they cause are not adequately controlled by fungicides, rotation or, for many hosts, natural genetic resistance. Although a combination of management practices are likely to be required for control of Rhizoctonia and Pythium, genetic resistance remains a key missing component. This review discusses the recent deployment of introduced genes and genome-based information for control of Rhizoctonia, with emphasis on three pathosystems: Rhizoctonia solani AG8 and wheat, R. solani AG1-IA and rice, and R. solani AG3 or AG4 and potato. Molecular mechanisms underlying disease suppression will be addressed, if appropriate. Although less is known about genes and factors suppressive to Pythium, pathogen genomics and biological control studies are providing useful leads to effectors and antifungal factors. Prospects for resistance to Rhizoctonia and Pythium spp. will continue to improve with growing knowledge of pathogenicity strategies, host defense gene action relative to the pathogen infection process, and the role of environmental factors on pathogen-host interactions. PMID:25438786
Laccase-mediated detoxification of phenolic compounds. [Rhizoctonia praticola
Bollag, J.M.; Shuttleworth, K.L.; Anderson, D.H. (Pennsylvania State Univ., University Park (USA))
The ability of a polyphenoloxidase, the laccase of the fungus Rhizoctonia praticola, to detoxify phenolic pollutants was examined. The growth of the fungus could be inhibited by phenolic compounds, and the effective concentration was dependent on the substituents of the phenol. A toxic amount of a phenolic compound was added to a fungal growth medium in the presence or absence of a naturally occurring phenol, and half of the replicates also received laccase. The medium was then inoculated with R. praticola, and the levels of phenols in the medium were monitored by high-performance liquid chromatography analysis. The addition of the laccase reversed the inhibitory effect of 2,6-xylenol, 4-chloro-2-methylphenol, and p-cresol. Other compounds, e.g., o-cresol and 2,4-dichlorophenol, were detoxified only when laccase was used in conjunction with a natural phenol such as syringic acid. The toxicity of p-chlorophenol and 2,4,5-trichlorophenol could not be overcome by any additions. The ability of the laccase to alter the toxicity of the phenols appeared to be related to the capacity of the enzyme to decrease the levels of the parent compound by transformation or cross-coupling with another phenol.
Rhizoctonia spp. associated with brown patch of St. Augustinegrass: isolate characterization, host range, and screening for resistance
Hurd, Bernadette Murphy
such as bluegrasses, fescues, bentgrasses, and rye- grasses. Environmental conditions for Rhizoctonia brown patch devel- opment can be at an optimum when cool season grasses are overseeded (19) ~ Z)awin et al (40) found that perennial ryegrasses developed seedling... 48 h of growth. 21 Fig. 3. Isolates of Rhizoctonia spp. collected from St. Augustine- grass and cultured on potato-dextrose agar 4 wk at 24 C. ) 9)4 . ):0)6 23 Fig. 4. Morphological characteristics of Rhizoctonia spp. isolated from St...
Rhizoctonia Crown and Root Rot Resistance of Beta PI's from the USDA-ARS NPGS, 2009.
Technology Transfer Automated Retrieval System (TEKTRAN)
Beta vulgaris plant introductions (PI) were screened for Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Research Farm. Inoculum of R. solani isolate R-9 (AG-2-2), colonized to dry barley and course ground, was applied to the crown of plants at a rate of 4.8 g/m. Beets were lifted...
Long Term Preservation of a Collection of Rhizoctonia Solani, using Cryogenic Storage
Technology Transfer Automated Retrieval System (TEKTRAN)
The fungus Rhizoctonia solani Kühn is an important plant pathogen on a number of crops and maintaining an extensive collection of reference isolates is important in understanding relationships of this pathogen with multiple hosts. While a number of long-term storage methods have been developed, mos...
Rhizoctonia in Container Grown Azalea, and Camellia Twig Blight: Incubation and Latency Periods
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. Disease severity was measured weekly in 'Gumpo' azalea plants spaced at distances of 0, 6, 12, 18, or 24 cm. Evaporative potential (EP), leaf wetness (LW), rela...
Chemical and Hot Water Treatments to Control Rhizoctonia on Infected Azalea Stem Cuttings
Technology Transfer Automated Retrieval System (TEKTRAN)
Spring shoot growth of azalea 'Gumpo White' used for propagation of stem cuttings can harbor binucleate Rhizoctonia species that cause web blight, thus the pathogen is unsuspectingly propagated with the plant. The objective of this study was to evaluate efficacy of disinfesting methods (commercially...
Postharvest respiration rate and sucrose concentration of Rhizoctonia-infected sugarbeet roots
Technology Transfer Automated Retrieval System (TEKTRAN)
The negative impact of Rhizoctonia crown and root rot (RCRR) on postharvest respiration, sugar concentration, and beet quality for roots with disease ratings of 2 or 3 is relatively small and would have only a small, and maybe immeasurable, effect on factory efficiency when mixed with healthy roots....
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight caused by the fungal pathogen Rhizoctonia solani is an emerging problem in rice production worldwide. To elucidate the molecular basis of rice defense to the pathogen, two RL-SAGE libraries were made from the R. solani infected and control plants of Jasmine 85, which is moderately resi...
Influence of Rhizoctonia-Bacterial root rot complex on storability of sugar beet
Technology Transfer Automated Retrieval System (TEKTRAN)
The root rot complex, caused by Rhizoctonia solani and Leuconostoc mesenteroides, can lead to yield loss in the field but may also lead to problems with sucrose loss in storage. Thus, studies were conducted to investigate if placing sugar beet roots suffering from root rot together with healthy roo...
RL-SAGE and microarray analysis of the rice defense transcriptome after Rhizoctonia solani infection
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight caused by the fungal pathogen Rhizoctonia solani is an emerging problem in rice production worldwide. To elucidate the molecular basis of rice defense to the pathogen, RNA isolated from R. solani-infected leaves of Jasmine 85 was used for both RL-SAGE library construction and microarra...
Technology Transfer Automated Retrieval System (TEKTRAN)
Abstract: Little is known about mechanisms of molecular interaction of hosts with the necrotrophic pathogen Rhizoctonia solani. Detailed analysis of the pathogen population in Arkansas, the major rice producing state in the USA, led to the identification of the most virulent field isolate out of a...
Influence of weed species and time of glyphosate application on Rhizoctonia root rot of barley
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia solani AG-8 causes root disease in wheat, barley, canola and other small grains in the dryland inland Pacific Northwest. The pathogen survives between crops on roots of volunteers and grassy weeds. Destroying this green bridge with herbicides such as glyphosate is a common tactic to cont...
Effect of Plant Spacing on Microclimate and Rhizoctonia Web Blight Development in Container Grown Azalea
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia web blight is a reoccurring problem in compact varieties of container-grown azalea (Rhododendron sp.) in the Gulf Coast States. During the summers of 2002 and 2003, disease severity was measured weekly in the inoculated center plant of plots consisting of 49 'Gumpo' azalea plants. Plant ...
Flooding causes loss in viability and pathogenicity of sclerotia of Rhizoctonia tuliparum
P. J. Muller; P. Vink; A. Van Zaayen
Samenvatting Rhizoctonia tuliparum veroorzaakt kwadegrond in tulp en iris. Sclerotiën van deze schimmel kunnen in grond zeer lang levensvatbaar en pathogeen blijven. Van sclerotiën van enkele schimmels is bekend, dat ze gevoelig zijn, voor inundatie die een aantal weken duurt. Inundatie wordt in Nederland vanaf 1982 door verscheidene, bollentelers 's zomers toegepast ter bestrijding van ziekten en onkruid.
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice sheath blight, caused by the fungal pathogen Rhizoctonia solani (AG1-IA), is an economically important disease in Arkansas. To identify the sheath blight resistance gene(s) an extensive molecular and pathological characterization of R., solani was initiated. A wide range of pathogen isolates ...
Spread potential of binucleate Rhizoctonia from propagation floors to trays containing stem cuttings
Technology Transfer Automated Retrieval System (TEKTRAN)
Binucelate Rhizoctonia spp. (BNR), the cause of web blight, are present all year on container-grown azaleas in the southern U.S. BNR can be eliminated during vegetative propagation by submerging stem cuttings in 50°C water for 21 minutes. The objective was to evaluate risk of rooting trays bein...
Real-time detection and quantification of Rhizoctonia and Pythium species on the Cook Agronomy Farm.
Technology Transfer Automated Retrieval System (TEKTRAN)
Populations of Rhizoctonia and Pythium are diverse in eastern Washington, with multiple species/anastomosis groups present throughout the region and within individual fields. The process of identifying the pathogen present in a sample is laborious and the high diversity increases the difficulty in a...
Incidence and spatial distribution of Rhizoctonia and Pythium species determined with real-time PCR
Technology Transfer Automated Retrieval System (TEKTRAN)
Populations of Rhizoctonia and Pythium are diverse in eastern Washington, with multiple species/anastomosis groups present throughout the region and within individual fields. Recent evidence suggests that species composition may be influenced by crop rotation. The Cook Agronomy Farm near Pullman, WA...
Stunting of onion caused by Rhizoctonia spp. isolated from the Columbia Basin of Oregon and Washington
Technology Transfer Automated Retrieval System (TEKTRAN)
During 2009 and 2010, 45 isolates of Rhizoctonia spp. were recovered from onion bulb crops in the semi-arid Columbia Basin of Oregon and Washington, in which patches of severely stunted onion plants developed following rotation with winter cereal cover crops. Characterization of isolates recovered f...
Bi-fluorescence imaging for estimating accurately the nuclear condition of Rhizoctonia spp.
Technology Transfer Automated Retrieval System (TEKTRAN)
Aims: To simplify the determination of the nuclear condition of the pathogenic Rhizoctonia, which currently needs to be performed either using two fluorescent dyes, thus is more costly and time-consuming, or using only one fluorescent dye, and thus less accurate. Methods and Results: A red primary ...
Distribution of Rhizoctonia Bare Patch and Root Rot in Eastern Washington and Relation to Climatic Variables
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia is a fungus that attacks the roots of wheat and barley, causing a root rot and bare patch in the dryland wheat cropping area of the inland Pacific Northwest. Over the last 7 years, we have been investigating the distribution of this pathogen, using molecular methods based on extracting a...
Genetic characterization of binucleate Rhizoctonia species causing web blight on azelea in Mississippi and Alabama
Technology Transfer Automated Retrieval System (TEKTRAN)
Web blight on containerized azalea is an annual problem for commercial nurseries during the summer months in the southern US. Losses to web blight are associated with the cost of fungicides, delayed marketing of diseased plants, and plant death. Three hundred and nine isolates of Rhizoctonia recover...
Long-term Preservation of a Collection of Rhizoctonia solani, using Cryogenic Storage
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia solani is an important plant pathogen on a number of crops and maintaining an extensive collection of reference isolates is important in understanding relationships of this pathogen with multiple hosts. Current long-term storage methods typically call for frequent transfer increasing the...
Development of reliable molecular markers to detect non- pathogenic binucleate Rhizoctonia isolates (AG-G) using PCR
Non-pathogenic binucleate Rhizoctonia species (BNR) belonging to the anastomosis group AG-G are commonly associated with members of the Rhizoctonia solani complex. They provide eective protection to young bean seedlings against root rot caused by R. solani AG-4. Both fungi are morphologically similar and it is dicult to dierentiate between them without using laborious conventional techniques. RAPD assays were carried out
The influence of cropping systems on inoculum density of Rhizoctonia solani and sheath blight of rice (Oryza sativa)
Belmar, Scott Bradley
LIST OF TABLES TABLE Page 1 Effect of cropping system on number and viability of recovered sclerotia of Rhizoctonia solani and incidence of sheath blight from fields surveyed in 1984 and 1985 15 2 Effect of alternative cropping practices... and duration of cropping practices on number and viability of recovered sclerotia of Rhizoctonia solani and incidence of sheath blight from fields surveyed in 1984 and 1985 16 3 Relationship between percentage of sites infested and diseased for 24 fields...
Stem Rot on Adzuki Bean (Vigna angularis) Caused by Rhizoctonia solani AG 4 HGI in China.
Sun, Suli; Xia, Changjian; Zhang, Jiqing; Duan, Canxing; Wang, Xiaoming; Wu, Xiaofei; Lee, Suk-Ha; Zhu, Zhendong
During late August and early September 2011, stem rot symptoms were observed on adzuki bean plants (Vigna angularis) growing in fields located in Beijing and Hebei Province, China, respectively. In this study, four isolates were obtained from infected stems of adzuki bean plants. Based on their morphology, and sequence and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses of the ribosomal DNA internal transcribed spacers (rDNA-ITS) region, the four isolates were identified as Rhizoctonia solani in anastomosis group (AG) 4 HGI. Pathogenicity tests showed that all isolates were strongly pathogenic to adzuki bean and resulted in serious wilt symptoms which was similar to observations in the fields. Additionally, the isolates infected several other crops and induced related rot on the roots and basal stems. To our knowledge, this is the first report of Rhizoctonia solani AG 4 HGI causing stem rot on adzuki bean. PMID:25774112
Infection process of Rhizoctonia solani on Solanum tuberosum and effects of granular nematicides
T. W. Hofman; P. H. J. Jongebloed
The infection process ofRhizoctonia solani AG-3 was studied on potato sprouts, cv. Bintje, in growth chamber trials at 15 °C. Initially hyphae ofR. solani grew predominantly in the longitudinal direction of the sprouts (runner hyphae). They tended to follow the junctions between epidermis cells as was observed by SEM. The hyphae formed side-branches mainly half-way of the subterranean parts of
The influence of cultural medium composition on the proteolytic enzyme secretion of fungus Rhizoctonia solani
N. N. Kudryavtseva; E. L. Gvozdeva; A. V. Sof'in; T. A. Valueva
It was shown that change of medium growth composition of photopathogenic fungus Rhizoctonia solani Kühn, especially accessible sources of nutrition, leads to change of both quantity of produced proteinases and their action\\u000a specificity. The mineral source of nitrogen suppressed the fungus proteinase secretion on cultivatiin medium containing potato\\u000a thermostable proteins but an organic source of nitrogen accelerated mycelium growth and
Antimycotic activities of Cinnamon-derived compounds against Rhizoctonia solani in vitro
Van-Nam Nguyen; Dang-Minh-Chanh Nguyen; Dong-Jun Seo; Ro-Dong Park; Woo-Jin Jung
In this study, the effects of medicinal plant extracts on the development of mycelium in the following phytopathogenic fungi\\u000a were evaluated: Phytophthora capsici, Rhizoctonia solani, Fusarium solani, Colletotrichum gloeosprorioides, and Botrytis cinera. Of the 26 medicinal plants tested, six plant extracts showed antifungal activity against phytopathogenic fungi. The highest\\u000a antifungal activity was exerted against R. solani by the n-hexane fraction
Effect of cultural conditions on the production of polygalacturonase by Rhizoctonia bataticola
A. C. Amadioha
Polygalacturonase (PG) activity was detected in culture filtrate and Rhizoctonia-infected tissues of potato tubers (Solanum tuberosum L.). Culture-produced PG formed more reducing groups than PG from diseased tissue. PG production and pH of the culture medium increased with the incubation period and attained optimal values between the 4th and 6th days. The ability of R. bataticola to produce PG varied
The effect of crop rotation and granular nematicides on the incidence of Rhizoctonia solani in potato
K. Scholte
The incidence ofRhizoctonia solani in potato was studied in two crop rotation experiments from 1981 to 1985 inclusive. The greater the frequency of potato cropping, the more severe the attack on stems and stolons byR. solani. Severity of black scurf on progeny tubers and cropping frequency were also correlated, but less significantly. In fields with antagonists toR. solani, continuous potato
Yield losses and damage to potato plants caused by Rhizoctonia solani Kuhn
G. J. Banville
Two field experiments conducted over three years at Les Buissons, Quebec demonstrated a causal relationship between the black\\u000a scurf stage and the disease phase ofRhizoctonia solani on potato cultivars Green Mountain and Norland.\\u000a \\u000a Planting sclerotia infested seed pieces as compared to sclerotia-free seed pieces resulted in a significant reduction in total\\u000a yield, marketable yield, number of tubers, mean tuber weight,
Trichoderma hamatum : Its hyphal interactions with Rhizoctonia solani and Pythium spp
I. Chet; G. E. Harman; R. Baker
The mode of hyphal interaction and parasitism ofPythium spp. andRhizoctonia solani byTrichoderma hamatum was studied by both phase-contrast and Nomarski differential interference-contrast microscopy. Directed growth of the mycoparasite toward its host was observed. In the area of interaction,T. hamatum produced appressorial-like structures attached to the host cell wall. Subsequently, several different types of interactions occurred.T. hamatum either grew parallel to
Biological control of Rhizoctonia solani in strawberry fields by Trichoderma harzianum
Yigal Elad; Ilan Chet; Yigal Henis
Summary \\u000a Trichoderma harzianum preparations was used in two successive field experiments in commercial strawberry nurseries and fruiting fields. Disease\\u000a severity ofRhizoctonia solani in daughter plants was reduced by 18–46 % in the treated nursery plots. Infestation of nursery soil with the pathogen, as\\u000a tested by planting beans in soil samples was reduced by the Trichoderma treatment by up to 92%
Control of Rhizoctonia solani and Sclerotium rolfsii in the greenhouse using endophytic Bacillus spp
Shlomo Pleban; Fanya Ingel; Ilan Chet
Isolates of different endophytic bacteria were recovered from surface-disinfected seeds obtained from commercial companies, plants in the field and tissue culture. The bacteria were isolated from seeds after stringent surfacedisinfection.Pseudomonas fluorescens (isolate no. 14) from bean inhibited growth of all fungi tested and was fluorescent on King B medium.Bacillus cereus fromSinapis (isolate no. 65) inhibited growth ofRhizoctonia solani, Pythium ultimum
The effect of tuber-borne sclerotia of Rhizoctonia solani Kühn on the potato crop
W. C. James; A. R. McKenzie
Black scurf on seed tubers did not result in seed decay or stem cankers and did not affect the tuber yield in two field experiments\\u000a at Ottawa and Fredericton. Seed pieces were classified into three disease categories: 0 to 1%, 1.1 to 5%, 5.1 to 15%, according\\u000a to the percentage surface area covered by sclerotia ofRhizoctonia solani. The difference between
Chemotaxonomy of fungi in the Rhizoctonia solani species complex performing GC\\/MS metabolite profiling
Konstantinos A. Aliferis; Marc A. Cubeta; Suha Jabaji
Hyphal anastomosis testing and molecular methods have been the primary criteria employed to understand the evolutionary and\\u000a taxonomic relationships of the soil-borne fungal plant pathogen Rhizoctonia solani species complex. In this study, a metabolomics-based approach for characterizing and identifying isolates of R. solani using gas chromatography\\/mass spectrometry (GC\\/MS) metabolite profiling and footprinting was developed. Multivariate and\\u000a hierarchical cluster analyses of
Antifungal activity of plant growth-promoting rhizobacteria isolates against Rhizoctonia solani in wheat
Zarrin Fatima; M. Saleemi; Muhammad Zia; T. Sultan; M. Aslam; M. Fayyaz Chaudhary
Seven plant growth-promoting rhizobacterial (PGPR) strains were isolated from the rhizoplane and rhizosphere of wheat from four different sites of Pakistan. These strains were analyzed for production of indole acetic acid (IAA), phosphorous solublization capability and inhibition of Rhizoctonia solani on rye agar medium. Strains WPR-51, WPR-42 and WM-30 were selected to test in planta antagonistic activity on two wheat
Characterization of Rhizoctonia solani Isolates Associated with Patch Diseases on Turfgrass
Stacy R. Blazier; Kenneth E. Conway
Cultural characteristics and pathogenicity of Rhizoctonia solani isolates obtained from brown patch on creeping bentgrass, Agrostis pulustris Huds. and large patch on zoysiagrass, Zoysia japonica Steud, were evaluated and compared with known R. solani anastomosis groups: AG-2-2III-B, AG-2-2IV, AG-1-IA, AG-4, and AG-5. Bentgrass and zoysiagrass isolates were obtained from infected grass leaf sheaths along disease patch margins. The bentgrass and
Antagonism against Rhizoctonia solani and fungitoxic metabolite production by some Penicillium isolates
R. Nicoletti; M. De Stefano; S. De Stefano; A. Trincone; F. Marziano
A number of Penicillium isolates were recovered in association to Rhizoctonia solani strains pathogenic on tobacco and from soil on plates pre-colonized by the pathogen itself. Their antagonism toward R. solaniAG-2-1 was evaluated in dual cultures in vitro. Inhibition of growth was evident to some extent in most pairings, while hyphal interactions referable to mycoparasitic relationships were not observed. However,
Intraspecific evolution of Rhizoctonia solani AG-1 IA associated with soybean and rice in Brazil based on polymorphisms at the ITS-5.8S rDNA operon
McDonald, Bruce
Intraspecific evolution of Rhizoctonia solani AG-1 IA associated with soybean and rice in Brazil words: anastomosis group, foliar blight, Thanatephorus cucumeris Abstract Rhizoctonia solani AG-1 IA fungus Thanatephorus cucumeris [anamorph=Rhizoctonia solani] is re- ported to cause economically
Rhizoctonia Crown and Root Rot Resistance of Beta Plant Introductions from the USDA, Agricultural Research Service's National Plant Germplasm System, 2010
Technology Transfer Automated Retrieval System (TEKTRAN)
Thirty wild beet (Beta vulgaris subsp. maritima (L.) Arcang) plant introduction (PI) accessions from the Beta collection of the USDA-ARS National Plant Germplasm System were screened for resistance to Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Research Farm. The Rhizoctonia sc...
Molecular characterisation of an endornavirus from Rhizoctonia solani AG-3PT infecting potato.
Das, Subha; Falloon, Richard E; Stewart, Alison; Pitman, Andrew R
Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is a soil-borne plant pathogenic fungus that has a broad host range, including potato. In this study, the double-stranded RNA (dsRNA) profiles were defined for 39 Rhizoctonia solani isolates representative of two different anastomosis groups (AGs) associated with black scurf of potato in New Zealand. A large dsRNA of c. 12 kb-18 kb was detected in each of the isolates, regardless of AG or virulence on potato. Characterisation of the large dsRNA from R. solani AG-3PT isolate RS002, using random amplification of total dsRNA and analyses of overlapping cDNA sequences, resulted in the assembly of a consensus sequence of 14?694 nt. A single, large open reading frame was identified on the positive strand of the assembled sequence encoding a putative polypeptide of at least 4893 amino acids, with a predicted molecular mass of 555.6 kDa. Conserved domains within this polypeptide included those for a viral methyltransferase, a viral RNA helicase 1 and an RNA-dependent RNA polymerase. The domains and their sequential organisation revealed the polyprotein was very similar to those encoded by dsRNA viruses of the genus Endornavirus, in the family Endornaviridae. This is the first report of an endornavirus in R. solani, and thus the putative virus is herein named Rhizoctonia solani endornavirus - RS002 (RsEV-RS002). Partial characterisation of the large dsRNAs in five additional AG-3PT isolates of R. solani also identified them as probable endornaviruses, suggesting this family of viruses is widespread in R. solani infecting potato. The ubiquitous nature of endornaviruses in this plant pathogen implies they may have an important, but yet uncharacterised, role in R. solani. PMID:25442295
Cropping Systems and Cultural Practices Determine the Rhizoctonia Anastomosis Groups Associated with Brassica spp. in Vietnam
Soltaninejad, Saman; Höfte, Monica
Ninety seven Rhizoctonia isolates were collected from different Brassica species with typical Rhizoctonia symptoms in different provinces of Vietnam. The isolates were identified using staining of nuclei and sequencing of the rDNA-ITS barcoding gene. The majority of the isolates were multinucleate R. solani and four isolates were binucleate Rhizoctonia belonging to anastomosis groups (AGs) AG-A and a new subgroup of A-F that we introduce here as AG-Fc on the basis of differences in rDNA-ITS sequence. The most prevalent multinucleate AG was AG 1-IA (45.4% of isolates), followed by AG 1-ID (17.5%), AG 1-IB (13.4%), AG 4-HGI (12.4%), AG 2-2 (5.2%), AG 7 (1.0%) and an unknown AG related to AG 1-IA and AG 1-IE that we introduce here as AG 1-IG (1.0%) on the basis of differences in rDNA-ITS sequence. AG 1-IA and AG 1-ID have not been reported before on Brassica spp. Pathogenicity tests revealed that isolates from all AGs, except AG-A, induced symptoms on detached leaves of several cabbage species. In in vitro tests on white cabbage and Chinese cabbage, both hosts were severely infected by AG 1-IB, AG 2-2, AG 4-HGI, AG 1-IG and AG-Fc isolates, while under greenhouse conditions, only AG 4-HGI, AG 2-2 and AG-Fc isolates could cause severe disease symptoms. The occurrence of the different AGs seems to be correlated with the cropping systems and cultural practices in different sampling areas suggesting that agricultural practices determine the AGs associated with Brassica plants in Vietnam. PMID:25372406
Identification of signatory secondary metabolites during mycoparasitism of Rhizoctonia solani by Stachybotrys elegans.
Chamoun, Rony; Aliferis, Konstantinos A; Jabaji, Suha
Stachybotrys elegans is able to parasitize the fungal plant pathogen Rhizoctonia solani AG-3 following a complex and intimate interaction, which, among others, includes the production of cell wall-degrading enzymes, intracellular colonization, and expression of pathogenic process encoding genes. However, information on the metabolome level is non-existent during mycoparasitism. Here, we performed a direct-infusion mass spectrometry (DIMS) metabolomics analysis using an LTQ Orbitrap analyzer in order to detect changes in the profiles of induced secondary metabolites of both partners during this mycoparasitic interaction 4 and 5 days following its establishment. The diketopiperazine(s) (DKPs) cyclo(S-Pro-S-Leu)/cyclo(S-Pro-S-Ile), ethyl 2-phenylacetate, and 3-nitro-4-hydroxybenzoic acid were detected as the primary response of Rhizoctonia 4 days following dual-culturing with Stachybotrys, whereas only the latter metabolite was up-regulated 1 day later. On the other hand, trichothecenes and atranones were mycoparasite-derived metabolites identified during mycoparasitism 4 and 5 days following dual-culturing. All the above secondary metabolites are known to exhibit bioactivity, including fungitoxicity, and represent key elements that determine the outcome of the interaction being studied. Results could be further exploited in programs for the evaluation of the bioactivity of these metabolites per se or their chemical analogs, and/or genetic engineering programs to obtain more efficient mycoparasite strains with improved efficacy and toxicological profiles. PMID:25972848
Differential expression of Phaseolus vulgaris genes induced during the interaction with Rhizoctonia solani.
Guerrero-González, M L; Rodríguez-Kessler, M; Rodríguez-Guerra, R; González-Chavira, M; Simpson, J; Sanchez, F; Jiménez-Bremont, J F
Common bean (Phaseolus vulgaris L.) is the most important grain legume for direct human consumption; however, bean production is affected by several diseases such as Rhizoctonia root rot. Few bean cultivars have been identified that effectively resist the attack of this fungus. Herein, we used the P. vulgaris Pv-2094 landrace, which is less susceptible to Rhizoctonia root rot, for the construction of a suppressive subtractive hybridization cDNA library in order to isolate plant defense-related genes. Total RNAs obtained after 8 and 16 h from inoculated and non-inoculated roots with R. solani Kühn, were used as the source of the "tester" and the "driver" samples, respectively. A total of 136 unigenes were obtained and classified into 12 functional categories. Six unigenes were selected to analyze for differential expression by qRT-PCR, including a receptor-like kinase (PvRK20-1), an acid phosphatase associated to defense (PA), a pathogenesis related protein (PR1), an ethylene responsive factor (ERF), a polygalacturonase inhibitor protein (PGIP), and an alpha-dioxygenase (?-DOX). These genes were found to be differentially expressed in a time-dependent manner in bean roots during the interaction with R. solani. Data generated from this study will contribute to the understanding of the molecular mechanisms associated with plant defense against root rot in common bean. PMID:21416283
Full genome sequence of a putative novel mitovirus isolated from Rhizoctonia cerealis.
Zhang, Tao; Li, Wei; Chen, Huaigu; Yu, Hanshou
A putative novel mitovirus was found in isolate R1084 of the fungus Rhizoctonia cerealis, the causal agent of sharp eyespot of wheat in China. The full genome sequence of the virus was determined and analyzed. The complete cDNA sequence is 3149 nucleotides long with 59.7 % A+T content. Using either the fungal mitochondrial or universal genetic code, the viral genome was found to contain a single large open reading frame that is predicted to encode a protein of 812 amino acids with an RNA-dependent RNA polymerase (RdRp) domain that is conserved in the mitovirus RdRp superfamily. The amino acid sequence of the RdRp domain is only 50 % identical to the corresponding domain in Sclerotinia sclerotiorum mitovirus 11, and therefore, this virus is proposed to be a novel mitovirus, designated as Rhizoctonia cerealis mitovirus 1-R1084 (RcMV1-R1084). The distinct codon usage of RcMV1-R1084 hints that this virus is potentially able to replicate not only in mitochondria but also in the cytoplasm. This is the first report of a full-length genomic sequence of a putative mitovirus in R. cerealis. PMID:25916611
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight, caused by the fungus Rhizoctonia solani, is a major disease of rice worldwide, but little is known about the host response to infection. The objective of this study was to identify proteins and DNA markers in resistant and susceptible rice associated with response to infection by R. s...
Sequence variation of the rDNA internal transcribed spacer (ITS) region among isolates of Rhizoctonia solani
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia solani is a common and highly heterogeneous fungal species. Sub-specific groups have been created based on hyphal anastomosis (AGs). One of the newer AGs described is AG-11 from soybean and rice seedlings or soil in Arkansas and lupine in Australia (Carling et al. Phytopathology 84:1378-...
Microbial populations involved in the suppression of Rhizoctonia solani AG1-1B by lignin incorporation in soil
Sarah Van Beneden; Dries Roobroeck; Soraya C. França; Stefaan De Neve; Pascal Boeckx; Monica Höfte
Rhizoctonia solani causes worldwide losses in numerous crops. Sclerotia of R. solani remain viable for several years in soil and are an important source of primary infection. In this study the effect of soil incorporation of Kraft pine lignin, a side product of the paper industry, on viability of R. solani AG1-1B sclerotia was investigated. The efficacy of lignin was
Identity and Specificity of Rhizoctonia-Like Fungi from Different Populations of Liparis japonica (Orchidaceae) in Northeast China
Ding, Rui; Chen, Xu-Hui; Zhang, Li-Jun; Yu, Xiao-Dan; Qu, Bo; Duan, Ru; Xu, Yu-Feng
Mycorrhizal association is known to be important to orchid species, and a complete understanding of the fungi that form mycorrhizas is required for orchid ecology and conservation. Liparis japonica (Orchidaceae) is a widespread terrestrial photosynthetic orchid in Northeast China. Previously, we found the genetic diversity of this species has been reduced recent years due to habitat destruction and fragmentation, but little was known about the relationship between this orchid species and the mycorrhizal fungi. The Rhizoctonia-like fungi are the commonly accepted mycorrhizal fungi associated with orchids. In this study, the distribution, diversity and specificity of culturable Rhizoctonia-like fungi associated with L. japonica species were investigated from seven populations in Northeast China. Among the 201 endophytic fungal isolates obtained, 86 Rhizoctonia-like fungi were identified based on morphological characters and molecular methods, and the ITS sequences and phylogenetic analysis revealed that all these Rhizoctonia-like fungi fell in the same main clade and were closely related to those of Tulasnella calospora species group. These findings indicated the high mycorrhizal specificity existed in L. japonica species regardless of habitats at least in Northeast China. Our results also supported the wide distribution of this fungal partner, and implied that the decline of L. japonica in Northeast China did not result from high mycorrhizal specificity. Using culture-dependent technology, these mycorrhizal fungal isolates might be important sources for the further utilizing in orchids conservation. PMID:25140872
Characterization of quantitative trait loci (QTLs) in cultivated rice contributing to field resistance to sheath blight ( Rhizoctonia solani )
Zhikang Li; S. R. M. Pinson; M. A. Marchetti; J. W. Stansel; W. D. Park
Sheath blight, caused by Rhizoctonia solani, is one of the most important diseases of rice. Despite extensive searches of the rice germ plasm, the major gene(s) which give complete resistance to the fungus have not been identified. However, there is much variation in quantitatively inherited resistance to R. solani, and this type of resistance can offer adequate protection against the
Draft Genome Sequence of the Plant-Pathogenic Soil Fungus Rhizoctonia solani Anastomosis Group 3 Strain Rhs1AP.
Cubeta, Marc A; Thomas, Elizabeth; Dean, Ralph A; Jabaji, Suha; Neate, Stephen M; Tavantzis, Stellos; Toda, Takeshi; Vilgalys, Rytas; Bharathan, Narayanaswamy; Fedorova-Abrams, Natalie; Pakala, Suman B; Pakala, Suchitra M; Zafar, Nikhat; Joardar, Vinita; Losada, Liliana; Nierman, William C
The soil fungus Rhizoctonia solani is a pathogen of agricultural crops. Here, we report on the 51,705,945 bp draft consensus genome sequence of R. solani strain Rhs1AP. A comprehensive understanding of the heterokaryotic genome complexity and organization of R. solani may provide insight into the plant disease ecology and adaptive behavior of the fungus. PMID:25359908
Pathogenicity, characterization and comparative virulence of Rhizoctonia spp. from insect-galled roots of Lepidium draba in Europe
Technology Transfer Automated Retrieval System (TEKTRAN)
The association of Rhizoctonia spp. with insect-damaged and diseased tissue of the invasive perennial Lepidium draba was documented throughout the range of L. draba that was surveyed in Europe, including Hungary, Austria, Switzerland and France. Samples that could be both maintained under cooled con...
Rapid Determination of Rice Cultivar Responses to the Sheath Blight Pathogen Rhizoctonia solani Using a Micro-Chamber Screening Method
Technology Transfer Automated Retrieval System (TEKTRAN)
An accurate greenhouse screening method has not previously been developed to identify host response to sheath blight disease caused by Rhizoctonia solani Kühn that causes significant economic losses in rice yield worldwide. The unavailability of a robust pathometric screening system in the greenhou...
Identification of Sugar Beet Germplasm EL51 as a Source of Resistance to Post-Emergence Rhizoctonia Damping-Off
Technology Transfer Automated Retrieval System (TEKTRAN)
The basidiomycete Rhizoctonia solani is a major agent of seedling stand declines in Michigan sugar beet production. Disease progress, starting from 2-week-old sugar beet seedlings, was scored daily over the following ca. two weeks in a controlled environment, using two AG-2-2 isolates and two AG-4 i...
Carbon source-dependent efficacy of anaerobic soil disinfestation (ASD) in suppression of Rhizoctonia root rot of apple
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia solani AG-5 is a significant component of the pathogen complex that incites apple replant disease (ARD). A non-fumigant alternative, such as ASD, is highly desired for control of ARD. We examined the influence of carbon input as a determinant of ASD efficacy in the supression of apple ...
Role of Bacterial Communities in the Natural Suppression of Rhizoctonia solani Bare Patch Disease of Wheat (Triticum aestivum L.)
Yin, Chuntao; Hulbert, Scot H.; Schroeder, Kurtis L.; Mavrodi, Olga; Mavrodi, Dmitri; Dhingra, Amit; Schillinger, William F.
Rhizoctonia bare patch and root rot disease of wheat, caused by Rhizoctonia solani AG-8, develops as distinct patches of stunted plants and limits the yield of direct-seeded (no-till) wheat in the Pacific Northwest of the United States. At the site of a long-term cropping systems study near Ritzville, WA, a decline in Rhizoctonia patch disease was observed over an 11-year period. Bacterial communities from bulk and rhizosphere soil of plants from inside the patches, outside the patches, and recovered patches were analyzed by using pyrosequencing with primers designed for 16S rRNA. Taxa in the class Acidobacteria and the genus Gemmatimonas were found at higher frequencies in the rhizosphere of healthy plants outside the patches than in that of diseased plants from inside the patches. Dyella and Acidobacteria subgroup Gp7 were found at higher frequencies in recovered patches. Chitinophaga, Pedobacter, Oxalobacteriaceae (Duganella and Massilia), and Chyseobacterium were found at higher frequencies in the rhizosphere of diseased plants from inside the patches. For selected taxa, trends were validated by quantitative PCR (qPCR), and observed shifts of frequencies in the rhizosphere over time were duplicated in cycling experiments in the greenhouse that involved successive plantings of wheat in Rhizoctonia-inoculated soil. Chryseobacterium soldanellicola was isolated from the rhizosphere inside the patches and exhibited significant antagonism against R. solani AG-8 in vitro and in greenhouse tests. In conclusion, we identified novel bacterial taxa that respond to conditions affecting bare patch disease symptoms and that may be involved in suppression of Rhizoctonia root rot and bare batch disease. PMID:24056471
Eˇect of bacterial antagonists on lettuce: active biocontrol of Rhizoctonia solani and negligible, short-term eˇects on nontarget microorganisms
Katja Scherwinski; Rita Grosch; Gabriele Berg
The aim of this study was to assess the biocontrol efficacy against Rhizoctonia solani of three bacterial antagonists introduced into naturally Rhizoctonia-infested lettuce fields and to analyse their impact on the indigenous plant-associated bacteria and fungi. Lettuce seedlings were inoculated with bacterial suspensions of two endophytic strains, Serratia plymuthica 3Re4-18 and Pseudomonas trivialis 3Re2-7, and with the rhizobacterium Pseudomonas fluorescens
Impact of biotic and a-biotic parameters on structure and function of microbial communities living on sclerotia of the soil-borne pathogenic fungus Rhizoctonia solani
Zachow, Christin; Grosch, Rita; Berg, Gabriele
The plant pathogen Rhizoctonia solani is very difficult to control due to its persistent, long-living sclerotial structures in soil. Sclerotia are the main source of infection for Rhizoctonia diseases, which cause high yield losses on a broad host range world-wide. Little is known about micro-organisms associated with sclerotia in soil. Therefore, microbial communities of greenhouse and field incubated Rhizoctonia sclerotia were analysed by a multiphasic approach. Using microbial fingerprints performed by PCR-SSCP, sclerotia-associated bacterial communities showed a high diversity, whereas only a few fungi could be detected. Statistical analysis of fingerprints revealed the influence of soil types, incubation conditions (greenhouse, field), and incubation time (5 and 12 weeks) on the bacterial as well as fungal community. No significant differences were found for the microbial community associated with different Rhizoctonia anastomosis sub-groups (AG 1-IB and AG 1-IC). Rhizoctonia sclerotia are an interesting bio-resource: high proportions of fungal cell-wall degrading isolates as well as those with antagonistic activity towards R. solani were found. While a fraction of 28.4% of sclerotia-associated bacteria (=40 isolates) with antagonistic properties was determined, only 4.4% (=6 isolates) of the fungal isolates were antagonistic. We identified strong antagonists of the genera Bacillus, Enterobacter, Pseudomonas, and Stenotrophomonas, which can be used as biological control agents incorporated in soil or applied to Rhizoctonia host plants.
Production of Chitinases and ?-1,3-Glucanases by Stachybotrys elegans, a Mycoparasite of Rhizoctonia solani
Tweddell, Russell J.; Jabaji-Hare, Suha H.; Charest, Pierre M.
The in vitro production of chitinases and ?-1,3-glucanases by Stachybotrys elegans, a mycoparasite of Rhizoctonia solani, was examined under various culture conditions, such as carbon and nitrogen sources, pH, and incubation period. Production of both enzymes was influenced by the carbon source incorporated into the medium and was stimulated by acidic pH and NaNO3. The activity of both enzymes was very low in culture filtrates from cells grown on glucose and sucrose compared with that detected on chitin (for chitinases) and cell wall fragments (for ?-1,3-glucanases). Protein electrophoresis revealed that, depending on the carbon source used, different isoforms of chitinases and ?-1,3-glucanases were detected. S. elegans culture filtrates, possessing ?-1,3-glucanase and chitinase activities, were capable of degrading R. solani mycelium. Images PMID:16349178
Expression of Dm-AMP1 in rice confers resistance to Magnaporthe oryzae and Rhizoctonia solani.
Jha, Sanjay; Tank, Harsukh G; Prasad, Bishun Deo; Chattoo, Bharat B
Magnaporthe oryzae and Rhizoctonia solani, are among the most important pathogens of rice, severely limiting its productivity. Dm-AMP1, an antifungal plant defensin from Dahlia merckii, was expressed in rice (Oryza sativa L. sp. indica cv. Pusa basmati 1) using Agrobacterium tumefaciens-mediated transformation. Expression levels of Dm-AMP1 ranged from 0.43% to 0.57% of total soluble protein in transgenic plants. It was observed that constitutive expression of Dm-AMP1 suppresses the growth of M. oryzae and R. solani by 84% and 72%, respectively. Transgenic expression of Dm-AMP1 was not accompanied by an induction of pathogenesis-related (PR) gene expression, indicating that the expression of DmAMP1 directly inhibits the pathogen. The results of in vitro, in planta and microscopic analyses suggest that Dm-AMP1 expression has the potential to provide broad-spectrum disease resistance in rice. PMID:18618285
Characterization and taxonomic placement of Rhizoctonia-like endophytes from orchid roots.
Shan, X C; Liew, E C Y; Weatherhead, M A; Hodgkiss, I J
Twenty-one Rhizoctonia-like fungal strains were isolated from the roots of four terrestrial orchid species from various locations in Hong Kong. The cultural morphology, nuclear number of the hyphal cell, pore ultrastructure, and RAPD and CAPS analyses of rDNA fragments revealed that most of these isolates were associated with the genera Ceratorhiza and Epulorhiza. RAPD analysis showed the presence of genetic diversity between the isolates from different hosts and locations. The compatibility between a selection of these Ceratorhiza and Epulorhiza isolates and 14 orchid species was determined using a symbiotic germination method. The germination and development of three orchid species, Arundina chinensis, Spathoglottis pubescens, and Spiranthes hongkongensis, were strongly stimulated by the Epulorhiza isolates. Habenaria dentata was found to form symbionts successfully with a Ceratorhiza isolate. PMID:21156492
Biocontrol efficacy of different isolates of Trichoderma against soil borne pathogen Rhizoctonia solani.
Asad, Saeed Ahmad; Ali, Naeem; Hameed, Abdul; Khan, Sabaz Ali; Ahmad, Rafiq; Bilal, Muhammad; Shahzad, Muhammad; Tabassum, Ayesha
In this study, the biocontrol abilities of water-soluble and volatile metabolites of three different isolates of Trichoderma (T. asperellum, T. harzianum and Trichoderma spp.) against soil borne plant pathogen Rhizoctonia solani were investigated both in vitro and in vivo. The results showed for the first time that mycelial growth inhibition of the pathogen was 74.4-67.8% with water-soluble metabolites as compared to 15.3-10.6% with volatile metabolites in vitro. In vivo antagonistic activity of Trichoderma isolates against R. solani was evaluated on bean plants under laboratory and greenhouse conditions. We observed that T. asperellum was more effective and consistent, lowering disease incidence up to 19.3% in laboratory and 30.5% in green house conditions. These results showed that three isolates of Trichoderma could be used as effective biocontrol agents against R. solani. PMID:25033669
Characterization and colonization of endomycorrhizal Rhizoctonia fungi in the medicinal herb Anoectochilus formosanus (Orchidaceae).
Jiang, Jr-Hau; Lee, Yung-I; Cubeta, Marc A; Chen, Lung-Chung
The medicinal effects and techniques for cultivating Anoectochilus formosanus are well-documented, but little is known about the mycorrhizal fungi associated with A. formosanus. Rhizoctonia (Thanatephorus) anastomosis group 6 (AG-6) was the most common species isolated from fungal pelotons in native A. formosanus and represented 67 % of the sample. Rhizoctonia (Ceratobasidium) AG-G, P, and R were also isolated and represent the first occurrence in the Orchidaceae. Isolates of AG-6, AG-R, and AG-P in clade I increased seed germination 44-91 % and promoted protocorm growth from phases III to VI compared to asymbiotic treatments and isolates of AG-G in clade II and Tulasnella species in clade III. All isolates in clades I to III formed fungal pelotons in tissue-cultured seedlings of A. formosanus, which exhibited significantly greater growth than nonmycorrhizal seedlings. An analysis of the relative effect of treatment ([Formula: see text]) showed that the low level of colonization ([Formula: see text]) by isolates in clade I resulted in a significant increase in seedling growth compared to isolates in clades II (0.63-0.82) and III (0.63-0.75). There was also a negative correlation (r?=?-0.8801) with fresh plant weight and fungal colonization. Our results suggest that isolates in clade I may represent an important group associated with native populations of A. formosanus and can vary in their ability to establish a symbiotic association with A. formosanus. The results presented here are potentially useful for advancing research on the medicinal properties, production, and conservation of A. formosanus in diverse ecosystems. PMID:25575732
Identification and functional analysis of AG1-IA specific genes of Rhizoctonia solani.
Ghosh, Srayan; Gupta, Santosh Kumar; Jha, Gopaljee
Rhizoctonia solani is an important necrotrophic fungal pathogen which causes disease on diverse plant species. It has been classified into 14 genetically distinct anastomosis groups (AGs), however, very little is known about their genomic diversity. AG1-IA causes sheath blight disease in rice and controlling this disease remains a challenge for sustainable rice cultivation. Recently the draft genome sequences of AG1-IA (rice isolate) and AG1-IB (lettuce isolate) had become publicly available. In this study, using comparative genomics, we report identification of 3,942 R. solani genes that are uniquely present in AG1-IA. Many of these genes encode important biological, molecular functions and exhibit dynamic expression during in-planta growth of the pathogen in rice. Based upon sequence similarity with genes that are required for plant and human/zoonotic diseases, we identified several putative virulence/pathogenicity determinants amongst AG1-IA specific genes. While studying the expression of 19 randomly selected genes, we identified three genes highly up-regulated during in-planta growth. The detailed in silico characterization of these genes and extent of their up-regulation in different rice genotypes, having variable degree of disease susceptibility, suggests their importance in rice-Rhizoctonia interactions. In summary, the present study reports identification, functional characterization of AG1-IA specific genes and predicts important virulence determinants that might enable the pathogen to grow inside hostile plant environment. Further characterization of these genes would shed useful insights about the pathogenicity mechanism of AG1-IA on rice. PMID:25070039
Enhanced iturin A production by Bacillus subtilis and its effect on suppression of the plant pathogen Rhizoctonia solani
S. Mizumoto; M. Hirai; M. Shoda
Enhanced production of the antibiotic iturin A by Bacillus subtilis RB14-CS reached 4.4 g L?1 in SM medium containing soybean meal and maltose, which was 16-fold and 2.2-fold higher than that in original and modified\\u000a number 3S media, respectively. When various volumes of RB14-CS cultures grown in SM medium were applied to pot tests of tomato\\u000a damping-off caused by Rhizoctonia solani,
Co-utilization of Bacillus subtilis and Flutolanil in controlling damping-off of tomato caused by Rhizoctonia solani
Maki Kondoh; Mitsuyo Hirai; Makoto Shoda
Damping-off of tomato caused by Rhizoctonia solani was controlled in a pot test using the biological agent, Bacillus subtilis RB14-C, and the chemical pesticide, Flutolanil. The co-utilization of B. subtilis RB14-C, and Flutolanil decreased the amount of Flutolanil used from 375 µg\\/pot when Flutolanil was used alone to 94 µg\\/pot, while exerting the same effect of reducing disease occurrence.
Impact of two soil-applied herbicides on damping-off of cowpea caused by Rhizoctonia solani
Hans R. Kataria; Dharam Singh Dodan
Summary Alachlor was more inhibitory toRhizoctonia solani growth than fluchloralin in potato dextrose broth (PDB). Infective capacity of the pathogen was not altered by growing it in a medium containing either of the herbicides. Cowpea seedlings grown in alachlor-treated soil were more susceptible toR. solani than those treated with fluchloralin and the untreated seedlings. Pre-sowing application of alachlor in soil
Effect of peat-bran inoculum of Trichoderma species on biological control of Rhizoctonia solani in lettuce
P. A. Maplestone; J. M. Whipps; J. M. Lynch
A range of known biocontrol or plant growth-stimulating species ofTrichoderma orGliocladium were grown on peat-bran substrate to yield between 5×107?3×1010 colony forming units (cfu's)g?1 substrate after 14 days growth. Inocula were incorporated into peat:sand potting compost infested withRhizoctonia solani to give 7–8 × 104 cfu's of antagonist g?1 compost and assessed for biological control activity using lettuce seedlings. Six of
Draft Genome Sequence of Pseudomonas simiae Strain 2-36, an In Vitro Antagonist of Rhizoctonia solani and Gaeumannomyces graminis.
Adam, Zaky; Chen, Qing; Xu, Renlin; Diange, Adolf E; Bromfield, Eden S P; Tambong, James Tabi
Pseudomonas simiae 2-36, isolated from a field plot under long-term mineral fertilization, exhibited strong in vitro antagonistic activities against Rhizoctonia solani and Gaeumannomyces graminis. We report here the draft genome sequence of Pseudomonas simiae 2-36, consisting of 6.4 Mbp with a 60.25% G+C content and 5,790 predicted protein-coding sequences. PMID:25657286
Biological control of Rhizoctonia solani on potatoes by antagonists. 1. Preliminary experiments with Verticillium biguttatum, a sclerotium-inhabiting fungus
H. Velvis; G. Jager
A common mycoparasite,Verticillium biguttatum, was found to kill sclerotia ofRhizoctonia solani placed on an inert material (perlite) as well as in soil at 15°C and 20°C, but not at 10°C. Compared with the effectivity ofV. biguttatum, that ofGliocladium roseum, Gliocladium nigrovirens, Hormiactis fimicola andTrichoderma hamatum on sclerotia was only low. In laboratory experiments, treatment of sclerotia-bearing seed potatoes withV. biguttatum
Formulation of a Streptomyces Biocontrol Agent for the Suppression of Rhizoctonia Damping-off in Tomato Transplants
Siva Sabaratnam; James A Traquair
Formulations of a Streptomyces biological control agent for Rhizoctonia damping-off in tomato seedlings were developed for the first time from vegetative propagules obtained from actively growing, nonsporulating liquid cultures. Alginate beads, durum flour (starch) granules, and talcum powder formulation of this new actinomycetous antagonist (Streptomyces sp. Di-944) isolated from the rhizosphere of field-grown tomato (Lycopersicon esculentum) suppressed damping-off caused by
Sequence variation of the rDNA ITS regions within and between anastomosis groups in Rhizoctonia solani
Shiro Kuninaga; Tomohide Natsuaki; Toru Takeuchi; Ryozo Yokosawa
Sequence analysis of the rDNA region containing the internal transcribed spacer (ITS) regions and the 5.8s rDNA coding sequence was used to evaluate the genetic diversity of 45 isolates within and between anastomosis groups (AGs)\\u000a in Rhizoctonia solani. The 5.8s rDNA sequence was completely conserved across all the AGs examined, whereas the ITS rDNA sequence was found to be highly
Draft Genome Sequence of Pseudomonas simiae Strain 2-36, an In Vitro Antagonist of Rhizoctonia solani and Gaeumannomyces graminis
Adam, Zaky; Chen, Qing; Xu, Renlin; Diange, Adolf E.; Bromfield, Eden S. P.
Pseudomonas simiae 2-36, isolated from a field plot under long-term mineral fertilization, exhibited strong in vitro antagonistic activities against Rhizoctonia solani and Gaeumannomyces graminis. We report here the draft genome sequence of Pseudomonas simiae 2-36, consisting of 6.4 Mbp with a 60.25% G+C content and 5,790 predicted protein-coding sequences. PMID:25657286
Biological control of Rhizoctonia solani on potatoes by antagonists. 3. Inoculation of seed potatoes with different fungi
P. H. J. E. Van Den Boogert; G. Jager
Inoculation of seed potatoes withVerticillium biguttatum and three other hyperparasitic fungi, alone or in combination, resulted in statistically significant reduction of infestation of potato plants byRhizoctonia solani. Gliocladium roseum, Trichoderma hamatum andHormiactis fimicola did not show prolonged protection againstR. solani under farming conditions.H. fimicola, however, inhibited mycelial growth ofR. solani in vitro, particularly in the lower temperature range whereV. biguttatum
Phytoalexin response is elicited by a pathogen ( Rhizoctonia solani ) but not by a mycorrhizal fungus ( Glomus mosseae ) in soybean roots
P. Wyss; T. Boller; A. Wiemken
Summary A container system was constructed to study the response of soybean roots to infection by mycorrhizal or pathogenic fungi. The system allows a rapid and synchronous inoculation byGlomus mosseae orRhizoctonia solani. The phytoalexin glyceollin was measured in roots of inoculated and uninoculated plants for a period of 30 days. A significantly increased content of phytoalexin was found inR. solani-infected
Identification of Rhizoctonia solani associated with field-grown tulips using ITS rDNA polymorphism and pectic zymograms
J. H. M. Schneider; O. Salazar; V. Rubio; J. Keijer
Methods based on internal transcribed spacers (ITS) ribosomal DNA (rDNA) polymorphism and pectic zymograms (ZG) were compared for their use in routine identification of Rhizoctonia solani isolates occurring in flower bulb fields. Thirty three AG 2-t isolates, pathogenic to tulips, could be distinguished from AG 1-IC, AG 2-2IIIB and AG 2-2IV, AG 3 and AG 5 by means of ITS
Biocontrol of damping-off of greenhouse-grown crops caused by Rhizoctonia solani with a formulation of Trichoderma spp
J. A Lewis; R. D Lumsden
A biocontrol formulation system which did not require sterile conditions during preparation consisted of mixing vermiculite, powdered wheat bran, and dry fermentor-produced biomass (FB) of isolates of Trichoderma and Gliocladium (VBA–FB) with 0.05MHCl and drying the mixture. Before addition to Rhizoctonia solani-infested soilless mix (Redi-Earth), the dry preparation (VBA–FB) was activated by remoistening with 0.05NHCl. After 2–3d of incubation at
The role of rhizosphere bacteria in herbicide-mediated increase in Rhizoctonia solani- induced cotton seedling damping-off
A. Heydari; I. J. Misaghi
A study was carried out to determine the role of rhizosphere-residing bacteria in the observed pendimethalin- and prometryn-mediated increase in cotton seedling damping-off incidence caused by Rhizoctonia solani. Judging from the results, pendimethalin-mediated increase in disease incidence may be due to a decrease in the populations of indigenous cotton root colonizing bacteria in the presence of pendimethalin. Prometryn-mediated increase in
Antifungal activity of volatile compounds-producing Pseudomonas P2 strain against Rhizoctonia solani.
Elkahoui, Salem; Djébali, Naceur; Yaich, Najeh; Azaiez, Sana; Hammami, Majdi; Essid, Rym; Limam, Ferid
Several volatile organic compounds (VOCs) producing endophyte bacteria were isolated from the leaves of olive trees and tested for their antifungal activity against several pathogenic fungi. An antagonistic strain called P2 showed 97 % of homology with Pseudomonas sp. strains on the basis of its 16S rDNA sequence and biochemical properties. P2 strain drastically inhibited the growth of Rhizoctonia solani mycelia (86 %) at 5 day-post-confrontation (dpc) and strongly reduced fungi infection on potato slices at 10(7) bacteria ml(-1) for 3 and 7 dpc. P2 strain was also positive for protease activity as well as siderophore production. Light microscopy analysis showed that treatment of R. solani mycelia with P2 strain induced thickening of the cell-wall, vesiculation of protoplasm and blockage of fungal hyphae branching. VOCs analysis using GC-MS allowed the detection of two major products with m/z of 93.9910 and 125.9630 corresponding to dimethyl disulfide and dimethyl trisulfide respectively. VOCs-producing P2 strain could be a promising agent in the protection of tuber crops against fungal diseases. PMID:25384611
Transcriptional responses of the bacterial antagonist Serratia plymuthica to the fungal phytopathogen Rhizoctonia solani.
Neupane, Saraswoti; Finlay, Roger D; Alström, Sadhna; Elfstrand, Malin; Högberg, Nils
Rhizobacteria with biocontrol ability exploit a range of mechanisms to compete successfully with other microorganisms and to ensure their growth and survival in the rhizosphere, ultimately promoting plant growth. The rhizobacterium Serratia plymuthica?AS13 is able to promote oilseed rape growth and improve seedling survival in the presence of the fungal pathogen, Rhizoctonia solani?AG 2-1; however, our understanding of the mechanisms underlying the antagonism of Serratia is limited. To elucidate possible mechanisms, genome-wide gene expression profiling of S.?plymuthica?AS13 was carried out in the presence or absence of R.?solani. We used RNA sequencing methodology to obtain a comprehensive overview of Serratia gene expression in response to R.?solani. The differential gene expression profiles of S.?plymuthica?AS13 revealed significantly increased expression of genes related to the biosynthesis of the antibiotic pyrrolnitrin (prnABCD), protease production and transporters. The results presented here provide evidence that antibiosis is a major functional mechanism underlying the antagonistic behaviour of S.?plymuthica?AS13. PMID:25139310
Efficacy of different fungicides against Rhizoctonia brown patch and Pythium blight on turfgrass in Italy.
Mocioni, M; Titone, P; Garibaldi, A; Gullino, M L
Brown patch, incited by Rhizoctonia solani Kuhn, and Pythium blight, caused by Pythium spp. are two of the diseases most frequently observed on turfgrass in high maintenance stands, as on golf courses. In such conditions the control strategies, based on chemicals, are particularly difficult due to the scarcity of fungicides registered for turf in Italy. The results obtained in experimental trials carried out to evaluate the efficacy of chemical and biological products against brown patch and Pythium blight are reported. On mature turfgrass, maintained under fairway conditions, azoxystrobin, and trifoxystrobin, not yet registered on turf, were very effective against brown patch. Tebuconazole, applied in three different formulations, was very effective against R. solani, while Trichoderma spp. and azadiractine did not control the pathogen. In greenhouse conditions on Agrostis stolonifera, in the presence of severe disease incidence, due to artificial inoculation, benalaxyl-M satisfactorily controlled Pythium blight; Trichoderma spp. as well as a commercial formulation of T. harzianum, applied one week before the inoculation, were not effective. Among the fungicides not yet registered for use on turfgrass in Italy, metalaxyl-M + mancozeb was effective against Pythium blight. PMID:15151284
Do fungicides used to control Rhizoctonia solani impact the non-target arbuscular mycorrhizal fungus Rhizophagus irregularis?
Buysens, Catherine; Dupré de Boulois, Hervé; Declerck, Stéphane
There is growing evidence that the application of biocontrol organisms (e.g., Pseudomonas and Bacillus spp., arbuscular mycorrhizal fungi-AMF) is a feasible option to reduce incidence of plant pathogens in an integrated control strategy. However, the utilization of these microorganisms, in particular AMF, may be threatened by the application of fungicides, a widely-used measure to control Rhizoctonia solani in various crops among which potato. Prior to their application, it is thus important to determine the impact of fungicides on AMF. The present study investigated, under in vitro controlled conditions, the impact of azoxystrobin (a systemic broad-spectrum fungicide), flutolanil (a systemic Basidiomycota-specific fungicide), and pencycuron (a contact Rhizoctonia-specific fungicide) and their respective formulations (Amistar, Monarch, and Monceren) on the growth and development of the AMF Rhizophagus irregularis MUCL 41833 (spore germination, root colonization, extraradical mycelium development, and spore production) at doses used to control R. solani. Results demonstrated that azoxystrobin and its formulation Amistar, at threshold values for R. solani control (estimated by the half maximal inhibitory concentration, IC50, on a dry weight basis), did not affect spore germination and potato root colonization by R. irregularis, while the development of extra-radical mycelium and spore production was reduced at 10 times the threshold value. Flutolanil and its formulation Monarch at threshold value did not affect spore germination or extra-radical development but decreased root colonization and arbuscule formation. At threshold value, pencycuron and its formulation Monceren, did not affect spore germination and intra- or extraradical development of R. irregularis. These results suggest that azoxystrobin and pencycuron do not affect the AMF at threshold concentrations to control R. solani in vitro, while flutolanil (as formulation) impacts the intraradical phase of the fungus. These fungicides and R. irregularis thus have the potential to be used in parallel against Rhizoctonia disease in potato. PMID:25312740
Agroecological factors correlated to soil DNA concentrations of Rhizoctonia in dryland wheat production zones of Washington state, USA.
Okubara, Patricia A; Schroeder, Kurtis L; Abatzoglou, John T; Paulitz, Timothy C
The necrotrophic soilborne fungal pathogens Rhizoctonia solani AG8 and R. oryzae are principal causal agents of Rhizoctonia root rot and bare patch of wheat in dryland cropping systems of the Pacific Northwest. A 3-year survey of 33 parcels at 11 growers' sites and 60 trial plots at 12 Washington State University cereal variety test locations was undertaken to understand the distribution of these pathogens. Pathogen DNA concentrations in soils, quantified using real-time polymerase chain reaction, were correlated with precipitation, temperature maxima and minima, and soil texture factors in a pathogen-specific manner. Specifically, R. solani AG8 DNA concentration was negatively correlated with precipitation and not correlated with temperature minima, whereas R. oryzae concentration was correlated with temperature minima but not with precipitation. However, both pathogens were more abundant in soils with higher sand and lower clay content. Principal component analysis also indicated that unique groups of meteorological and soil factors were associated with each pathogen. Furthermore, tillage did not affect R. oryzae but affected R. solani AG8 at P = 0.06. Lower soil concentrations of R. solani AG8 but not R. oryzae occurred when the previously planted crop was a broadleaf (P < 0.05). Our findings showed that R. solani AG8 concentrations were consistent with the general distribution of bare patch symptoms, based on field observations and surveys of other pathogens, but was present at many sites in which bare patch symptoms were not evident. Management of Rhizoctonia root rot and bare patch should account for the likelihood that each pathogen is affected by a unique group of agroecological variables. PMID:24915426
A comparison of in vitro and in vivo effect of clay minerals, humic acid and micronutrients on the activity of fungicides against Rhizoctonia solani
Hans R. Kataria; Shyam Sunder
Activity of nine fungicides against mycelial growth ofRhizoctonia solani in potato dextrose broth and in pot tests as seed treatment against cowpea seedling rot in infested soil was differentially in fluenced by clay minerals, humic acid and micronutrients. Humic acid, extracted from farmyard manure, considerably lowered the activity, bothin vitro andin vivo, of all fungicides except chloroneb. Montmorillonite caused substantial
Mid-infared (MidIR) and near-infared (NIR) dection of rhizoctonia solani AG 2-2 IIIB on barley based artificial inoculum
Technology Transfer Automated Retrieval System (TEKTRAN)
The amount of Rhizoctonia solani in the soil and how much is needed to cause disease in sugar beet (Beta vulgaris L.) is relatively unknown. This is mostly because of the usually low inoculum densities natually found in soil, and the low sensitivity of traditional serial dilution assays. We invest...
Efficacy of fungicides to manage onion stunting caused by Rhizoctonia spp. in the Columbia Basin of Oregon and Washington, 2011-2012
Technology Transfer Automated Retrieval System (TEKTRAN)
Onion stunting, caused by Rhizoctonia spp., has become a significant soilborne problem of onion bulb crops planted in sandy soils in the semi-arid Columbia Basin of Oregon and Washington following winter cereal cover crops. Research on the epidemiology and management of this disease is in progress. ...
Release of SR98 Sugarbeet Germplasm with High Levels of Resistance to Rhizoctonia Damping-Off, Crown and Root Rot, and Fusarium
Technology Transfer Automated Retrieval System (TEKTRAN)
SR98 (PI 655951) is a sugarbeet germplasm with smooth, low soil tare root and high levels of resistance to damping-off and crown and root rot caused by Rhizoctonia solani (AG2-2). Previous smooth–root releases have been highly susceptible to diseases caused by R. solani, and the SR98 has incorporate...
High-resolution mapping of Rsn1, a locus controlling sensitivity of rice to a necrosis-inducing phytotoxin from Rhizoctonia solani AG1-IA
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia solani is a necrotrophic fungal pathogen that causes disease on all major crop-plant species. Anastomosis group 1-IA is the causal agent of sheath blight of rice (Oryza sativa), one of the most important rice diseases worldwide. R. solani AG-IA produces a necrosis-inducing phytotoxin a...
Technology Transfer Automated Retrieval System (TEKTRAN)
Brassica tissues are often promoted as a soil amendment for control of soilborne plant disease due to their production of glucosinolates, which yield anti-microbial compounds upon hydrolysis. Studies demonstrated that control of Rhizoctonia root rot of apple in response to Brassica napus seed meal ...
Effect of two vesicular-arbuscular mycorrhizal fungi on the growth of micropropagated potato plantlets and on the extent of disease caused by Rhizoctonia solani
M. K. Yao; R. J. Tweddell; H. Désilets
Two micropropagated potato cultivars, Goldrush and LP89221, were inoculated into sowing trays with either Glomus etunicatum or G. intraradices in a greenhouse. After 2 weeks, plantlets were transplanted into pots and roots were challenged 7 days later with Rhizoctonia solani. At different times after R. solani infection, disease severity, mortality rate, root colonization levels, various growth parameters, and shoot mineral
Sanitation Can Be A Foundation Disease Management Tool: Potential Of Spreading Binucleate Rhizoctonia from Nursery Propagation Floors To Trays Containing Azalea Stem Cuttings
Technology Transfer Automated Retrieval System (TEKTRAN)
Binucelate Rhizoctonia spp. (BNR), the cause of web blight, are present all year on container-grown azaleas in the southern U.S. BNR can be eliminated during vegetative propagation by submerging stem cuttings in 50°C water for 21 minutes. The objective was to evaluate risk of rooting trays being con...
Rhizoctonia spp. dynamics and optimal timing of glyphosate application to cereal cover crops to manage onion stunting in Washington and Oregon
Technology Transfer Automated Retrieval System (TEKTRAN)
Onion stunting or bare patch caused by Rhizoctonia spp. is an economically important disease in sandy soils of the Columbia Basin of Oregon and Washington. Patches of stunted onions develop where cover crops of wheat or barley are killed with a herbicide spray prior to spring planting of onion seed....
Integrated options for the management of black root rot of strawberry caused by Rhizoctonia solani Kuhn.
Asad-Uz-Zaman, Md; Bhuiyan, Mohammad Rejwan; Khan, Mohammad Ashik Iqbal; Alam Bhuiyan, Md Khurshed; Latif, Mohammad Abdul
An investigation was made to manage strawberry black root rot caused by Rhizoctonia solani (R. solani) through the integration of Trichoderma harzianum (T. harzianum) isolate STA7, mustard oil cake and Provax 200. A series of preliminary experiments were conducted to select a virulent isolate of R. solani, an effective isolate of T. harzianum, a suitable organic amendment, and a suitable fungicide before setting the experiment for integration. The pathogenicity of the selected four isolates of R. solani was evaluated against strawberry and isolate SR1 was selected as the test pathogen due to its highest virulent (95.47% mortality) characteristics. Among the 20 isolates of T. harzianum, isolate STA7 showed maximum inhibition (71.97%) against the test pathogen (R. solani). Among the fungicides, Provax-200 was found to be more effective at lowest concentration (100 ppm) and highly compatible with Trichoderma isolates STA7. In the case of organic amendments, maximum inhibition (59.66%) of R. solani was obtained through mustard oil cake at the highest concentration (3%), which was significantly superior to other amendments. Minimum percentages of diseased roots were obtained with pathogen (R. solani)+Trichoderma+mustard oil cake+Provax-200 treatment, while the highest was observed with healthy seedlings with a pathogen-inoculated soil. In the case of leaf and fruit rot diseases, significantly lowest infected leaves as well as fruit rot were observed with a pathogen+Trichoderma+mustard oil cake+Provax-200 treatment in comparison with the control. A similar trend of high effectiveness was observed by the integration of Trichoderma, fungicide and organic amendments in controlling root rot and fruit diseases of strawberry. Single application of Trichoderma isolate STA7, Provax 200 or mustard oil cake did not show satisfactory performance in terms of disease-free plants, but when they were applied in combination, the number of healthy plants increased significantly. The result of the current study suggests the superiority of our integrated approach to control the sclerotia forming pathogen R. solani compared to the individual treatment either by an antagonist or by a fungicide or by mustard oil cake. PMID:25595298
Genome Sequencing and Comparative Genomics of the Broad Host-Range Pathogen Rhizoctonia solani AG8
Hane, James K.; Anderson, Jonathan P.; Williams, Angela H.; Sperschneider, Jana; Singh, Karam B.
Rhizoctonia solani is a soil-borne basidiomycete fungus with a necrotrophic lifestyle which is classified into fourteen reproductively incompatible anastomosis groups (AGs). One of these, AG8, is a devastating pathogen causing bare patch of cereals, brassicas and legumes. R. solani is a multinucleate heterokaryon containing significant heterozygosity within a single cell. This complexity posed significant challenges for the assembly of its genome. We present a high quality genome assembly of R. solani AG8 and a manually curated set of 13,964 genes supported by RNA-seq. The AG8 genome assembly used novel methods to produce a haploid representation of its heterokaryotic state. The whole-genomes of AG8, the rice pathogen AG1-IA and the potato pathogen AG3 were observed to be syntenic and co-linear. Genes and functions putatively relevant to pathogenicity were highlighted by comparing AG8 to known pathogenicity genes, orthology databases spanning 197 phytopathogenic taxa and AG1-IA. We also observed SNP-level "hypermutation" of CpG dinucleotides to TpG between AG8 nuclei, with similarities to repeat-induced point mutation (RIP). Interestingly, gene-coding regions were widely affected along with repetitive DNA, which has not been previously observed for RIP in mononuclear fungi of the Pezizomycotina. The rate of heterozygous SNP mutations within this single isolate of AG8 was observed to be higher than SNP mutation rates observed across populations of most fungal species compared. Comparative analyses were combined to predict biological processes relevant to AG8 and 308 proteins with effector-like characteristics, forming a valuable resource for further study of this pathosystem. Predicted effector-like proteins had elevated levels of non-synonymous point mutations relative to synonymous mutations (dN/dS), suggesting that they may be under diversifying selection pressures. In addition, the distant relationship to sequenced necrotrophs of the Ascomycota suggests the R. solani genome sequence may prove to be a useful resource in future comparative analysis of plant pathogens. PMID:24810276
First Report of Web Blight of Rosemary (Rosmarinus officinalis) Caused by Rhizoctonia solani AG-1-IB in Korea
Aktaruzzaman, Md.; Kim, Joon-Young; Afroz, Tania
Herein, we report the first occurrence of web blight of rosemary caused by Rhizoctonia solani AG-1-IB in Gangneung, Gangwon Province, Korea, in August 2014. The leaf tissues of infected rosemary plants were blighted and white mycelial growth was seen on the stems. The fungus was isolated from diseased leaf tissue and cultured on potato dextrose agar for identification. The young hyphae had acute angular branching near the distal septum of the multinucleate cells and mature hyphal branches formed at an approximately 90° angle. This is morphologically identical to R. solani AG-1-IB, as per previous reports. rDNA-ITS sequences of the fungus were homologous to those of R. solani AG-1-IB isolates in the GenBank database with a similarity percentage of 99%, thereby confirming the identity of the causative agent of the disease. Pathogenicity of the fungus in rosemary plants was also confirmed by Koch's postulates.
Effects of an isolate of Rhizoctonia solani Kühn AG8 from diseased barley on the growth and infection of potatoes ( Solanum tuberosum L.)
G. A. Hide; Janet P. Firmager
Summary An isolate ofRhizoctonia solani AG8 from a barley plant affected with barley stunt was incorporated into soil and caused severe stunting of cv. Dsire potatoes\\u000a grown in pots. Fresh weight of foliage, stem bases, roots and tubers were greatly decreased. Most main roots were pruned off\\u000a and a large number of lateral roots developed, resulting in an unusually fibrous root
Soil type, management history, and soil amendments influence the development of soil-borne ( Rhizoctonia solani , Pythium ultimum ) and air-borne ( Phytophthora infestans , Hyaloperonospora parasitica ) diseases
Lucius Tamm; Barbara Thürig; Christian Bruns; Jacques G. Fuchs; Ulrich Köpke; Matias Laustela; Carlo Leifert; Nicole Mahlberg; Bruno Nietlispach; Christoph Schmidt; Felix Weber; Andreas Fließbach
The impact of soil type, long-term soil management, and short-term fertility input strategies on the suppressiveness of soils\\u000a against soil-borne (Ocimum basilicum – Rhizoctonia solani, Lepidium sativum – Pythium ultimum) as well as air-borne (Lycopersicon esculentum – Phytophthora infestans, Arabidopsis thaliana – Hyaloperonospora parasitica) diseases was studied. Soils from field trials established in five European sites with contrasting pedo-climatic conditions
The effect of pH on the transformation of syringic and vanillic acids by the laccases of Rhizoctonia praticola and Trametes versicolor
A. Leonowicz; R. U. Edgehill; J.-M. Bollag
Laccases (benzenediol: oxygen oxidoreductases, EC 22.214.171.124) from Rhizoctonia praticola and Trametes versicolor formed different products from syringic and vanillic acids at different pH values, but both enzymes generated the same chemicals at a particular pH. The products were separated by thin-layer and high-performance liquid chromatography. Four compounds were determined from syringic acid (m\\/z 168, 334, 350 and 486) at pH
Biological control of Rhizoctonia solani on potatoes by antagonists. 4. Inoculation of seed tubers with Verticillium biguttatum and other antagonists in field experiments
G. Jager; H. Velvis
Inoculation of seed potatoes with the mycoparasiteVerticillium biguttatum, isolate M73 (combined withGliocladium roseum in 1981, either alone or mixed with isolate M180 plus antibiotics-producing isolates ofAzotobacter chroococcum in 1982) repeatedly proved successful in reducingRhizoctonia solani on stolons and stems. In field experiments, this ultimately led to a reduced formation of sclerotia on new tubers, particularly in neutral sandy loam and
A gene for plant protection: expression of a bean polygalacturonase inhibitor in tobacco confers a strong resistance against Rhizoctonia solani and two oomycetes.
Borras-Hidalgo, Orlando; Caprari, Claudio; Hernandez-Estevez, Ingrid; Lorenzo, Giulia De; Cervone, Felice
We have tested whether a gene encoding a polygalacturonase-inhibiting protein (PGIP) protects tobacco against a fungal pathogen (Rhizoctonia solani) and two oomycetes (Phytophthora parasitica var. nicotianae and Peronospora hyoscyami f. sp. tabacina). The trials were performed in greenhouse conditions for R. solani and P. parasitica and in the field for P. hyoscyami. Our results show that expression of PGIP is a powerful way of engineering a broad-spectrum disease resistance. PMID:23264779
A gene for plant protection: expression of a bean polygalacturonase inhibitor in tobacco confers a strong resistance against Rhizoctonia solani and two oomycetes
Borras-Hidalgo, Orlando; Caprari, Claudio; Hernandez-Estevez, Ingrid; Lorenzo, Giulia De; Cervone, Felice
We have tested whether a gene encoding a polygalacturonase-inhibiting protein (PGIP) protects tobacco against a fungal pathogen (Rhizoctonia solani) and two oomycetes (Phytophthora parasitica var. nicotianae and Peronospora hyoscyami f. sp. tabacina). The trials were performed in greenhouse conditions for R. solani and P. parasitica and in the field for P. hyoscyami. Our results show that expression of PGIP is a powerful way of engineering a broad-spectrum disease resistance. PMID:23264779
Isolation and characterization of a novel wheat cysteine-rich receptor-like kinase gene induced by Rhizoctonia cerealis
NASA Astrophysics Data System (ADS)
Yang, Kun; Rong, Wei; Qi, Lin; Li, Jiarui; Wei, Xuening; Zhang, Zengyan
Cysteine-rich receptor kinases (CRKs) belong to the receptor-like kinase family. Little is known about CRK genes in wheat. We isolated a wheat CRK gene TaCRK1 from Rhizoctonia cerealis-resistant wheat CI12633 based on a differentially expressed sequence identified by RNA-Sequencing (RNA-Seq) analysis. TaCRK1 was more highly expressed in CI12633 than in susceptible Wenmai 6. Transcription of TaCRK1 in wheat was induced in CI12633 after R. cerealis infection and exogenous abscisic acid (ABA) treatment. The deduced TaCRK1 protein contained a signal peptide, two DUF26 domains, a transmembrane domain, and a serine/threonine protein kinase domain. Transient expression of a green fluorescence protein fused with TaCRK1 in wheat and onion indicated that TaCRK1 may localize to plasma membranes. Characterization of TaCRK1 silencing induced by virus-mediated method in CI12633 showed that the downregulation of TaCRK1 transcript did not obviously impair resistance to R. cerealis. This study paves the way to further CRK research in wheat.
Investigating the roles of MicroRNAs in biotic stress response induced by Rhizoctonia solani in rice
NASA Astrophysics Data System (ADS)
Syuhada, O. Nurfarahana; Kalaivani, N.
Sheath blight disease, caused by Rhizoctonia solani 1802/KB was screened on two rice varieties, Oryza sativaindica cultivar MR219 and Oryza sativa indica cultivar UKMRC9. The disease symptom was severe in MR219 compared to UKMRC9. Total RNA from R. solani 1802/KB, infected rice leaves of MR219 and infected rice leaves of UKMRC9 were extracted using TRIzol reagent, purified and sent for small RNA sequencing. Three miRNA libraries were generated and analyzed. The libraries generated 65 805, 78 512 and 81 325 known miRNAs respectively. The structure of miRNA of these samples was predicted. The up-regulated and down-regulated of miRNAs target gene prediction and its target functions were discovered and were mainly related to the growth and development of metabolism, protein transport, transcriptional regulation, stress response, and hormone signaling and electron transfer. Sheath blight-induced differential expression of known miRNAs tends to targetMYB transcription factor, F-box proteins, NBS-LRR, leucine-rich repeat receptor protein kinases and zinc finger proteins. Detecting new miRNAs and measuring the expression profiles of known miRNAs is an important tasks required for a better understanding of various biological conditions. Therefore, further analysis using Gene Ontology Slim will be conducted to deduce some biological information from the datasets obtained.
Investigating the roles of MicroRNAs in biotic stress response induced by Rhizoctonia solani in rice
Syuhada, O. Nurfarahana; Kalaivani, N. [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)
Sheath blight disease, caused by Rhizoctonia solani 1802/KB was screened on two rice varieties, Oryza sativaindica cultivar MR219 and Oryza sativa indica cultivar UKMRC9. The disease symptom was severe in MR219 compared to UKMRC9. Total RNA from R. solani 1802/KB, infected rice leaves of MR219 and infected rice leaves of UKMRC9 were extracted using TRIzol reagent, purified and sent for small RNA sequencing. Three miRNA libraries were generated and analyzed. The libraries generated 65 805, 78 512 and 81 325 known miRNAs respectively. The structure of miRNA of these samples was predicted. The up-regulated and down-regulated of miRNAs target gene prediction and its target functions were discovered and were mainly related to the growth and development of metabolism, protein transport, transcriptional regulation, stress response, and hormone signaling and electron transfer. Sheath blight-induced differential expression of known miRNAs tends to targetMYB transcription factor, F-box proteins, NBS-LRR, leucine-rich repeat receptor protein kinases and zinc finger proteins. Detecting new miRNAs and measuring the expression profiles of known miRNAs is an important tasks required for a better understanding of various biological conditions. Therefore, further analysis using Gene Ontology Slim will be conducted to deduce some biological information from the datasets obtained.
Rhizoctonia bataticola lectin (RBL) induces phenotypic and functional characteristics of macrophages in THP-1 cells and human monocytes.
Pujari, Radha; Kumar, Natesh; Ballal, Suhas; Eligar, Sachin M; Anupama, S; Bhat, Ganapati; Swamy, Bale M; Inamdar, Shashikala R; Shastry, Padma
We have previously reported that a fungal lectin, Rhizoctonia bataticola lectin (RBL), stimulates proliferation and secretion of Th1/Th2 cytokines in human peripheral blood mononuclear cells (PBMC). In the present study, we evaluated the ability of RBL to differentiate human monocytes to macrophages. RBL induced morphological changes indicative of differentiation in primary monocytes and THP-1 cells. Stimulation with RBL resulted in significant up-regulation of differentiation markers - CD54, HLA-DR, CD11b and CD11c and secretion of proinflammatory cytokines - IL-1?, TNF-? and IL-6. Functionally, RBL profoundly increased phagocytic activity in monocytes. In THP-1 cells, RBL-induced phagocytosis was higher compared to the effect induced by combination of phorbol-12-myristate-13-acetate (PMA) and lipopolysaccharide (LPS). RBL induced a significant increase in matrix metalloproteinase-9 (MMP-9) activity in comparison with a combined treatment of PMA+LPS. Mechanistic studies revealed the involvement of the NF-?B pathway in RBL-induced differentiation of monocytes. The data suggest that RBL mimics the combined action of PMA and LPS to induce morphological and functional differentiation in human monocytes and monocytic cell line - THP-1 to macrophages. Human monocytes differentiated to macrophages with RBL have the potential as an in vitro model to study macrophage biology. PMID:25555439
Development of controlled release nanoformulations of carbendazim employing amphiphilic polymers and their bioefficacy evaluation against Rhizoctonia solani.
Koli, Pushpendra; Singh, Braj B; Shakil, Najam A; Kumar, Jitendra; Kamil, Deeba
Controlled release nanoformulations of carbendazim (Methyl 1H-benzimidazol-2-ylcarbamate), a systemic fungicide, have been prepared using laboratory synthesized poly(ethylene glycols) (PEGs)-based functionalized amphiphilic copolymers. The release kinetics of carbendazim from developed controlled release (CR) formulations was studied and compared with that of the commercially available 50% Wettable Powder (WP). Further, the bioefficacy evaluation of developed formulations was done against plant pathogenic fungi Rhizoctonia solani by the poison food technique method. The release of maximum amount of carbendazim from developed formulations was dependent on the molecular weight of PEGs and was found to increase with increasing molecular weights. The range of carbendazim release was found to be between 10th to 35th day as compared to commercial formulation which was up to 7th day. The diffusion exponent (n value) of carbendazim in water ranged from 0.37 to 0.52 in the tested formulations. The half-release (t1/2) values ranged between 9.47 and 24.20 days, and the period of optimum availability (POA) of carbendazim ranged from 9.15 to 26.63 days. Also, ED50 values of the developed formulations vary from 0.40 to 0.74 mg L(-1). These formulations can be used to optimize the release of carbendazim to achieve disease control for the desired period depending on the matrix of the polymer used. PMID:26079342
Induction of systemic resistance in rice by leaf extracts of Zizyphus jujuba and Ipomoea carnea against Rhizoctonia solani
Marimuthu, Thambiayya; Kagale, Jayashree; Thayumanavan, Balsamy; Samiyappan, Ramasamy
Plants accumulate a great diversity of natural products, many of which confer protective effects against phytopathogenic attack. Earlier we had demonstrated that the leaf extracts of Zizyphus jujuba and Ipomoea carnea inhibit the in vitro mycelial growth of Rhizoctonia solani, and effectively reduce the incidence of sheath blight disease in rice.7 Here we demonstrate that foliar application of the aqueous leaf extracts of Z. jujuba and I. carnea followed by challenge inoculation with R. solani induces systemic resistance in rice as evident from significantly increased accumulation of pathogenesis-related proteins such as chitinase, ?-1,3-glucanase and peroxidase, as well as defense-related compounds such as phenylalanine ammonia-lyase and phenolic substances. Thin layer chromatographic separation of secondary metabolites revealed presence of alkaloid and terpenoid compounds in the leaf extracts of Z. jujuba that exhibited toxicity against R. solani under in vitro condition. Thus, the enhanced sheath blight resistance in rice seedlings treated with leaf extracts of Z. jujuba or I. carnea can be attributed to the direct inhibitory effects of these leaf extracts as well as their ability to elicit systemic resistance against R. solani. PMID:21593600
Solanioic Acid, an Antibacterial Degraded Steroid Produced in Culture by the Fungus Rhizoctonia solani Isolated from Tubers of the Medicinal Plant Cyperus rotundus.
Ratnaweera, Pamoda B; Williams, David E; Patrick, Brian O; de Silva, E Dilip; Andersen, Raymond J
Solanioic acid (1), a degraded and rearranged steroid that exhibits in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), has been isolated from laboratory cultures of the fungus Rhizoctonia solani obtained from tubers of the plant Cyperus rotundus collected in Sri Lanka. The structure of solanioic acid (1) was elucidated by detailed analysis of NMR data, a single crystal X-ray diffraction analysis of a reduction product 2, and Mosher ester analysis on a derivative of the natural product. Solanioic acid (1) has an unprecedented carbon skeleton. PMID:25860081
Characterization of antagonistic-potential of two Bacillus strains and their biocontrol activity against Rhizoctonia solani in tomato.
Solanki, Manoj Kumar; Singh, Rajesh Kumar; Srivastava, Supriya; Kumar, Sudheer; Kashyap, Prem Lal; Srivastava, Alok K
To investigate the biocontrol mechanism of two antagonistic Bacillus strains (Bacillus subtilis MB14 and Bacillus amyloliquefaciens MB101), three in vitro antagonism assays were screened and the results were concluded that both strains inhibited Rhizoctonia solani growth in a similar manner by dual culture assay, but the maximum percent of inhibition only resulted with MB101 by volatile and diffusible metabolite assays. Moreover, cell free supernatant (CFS) of MB101 also showed significant (p?>?0.05) growth inhibition as compared to MB14, when 10 and 20% CFS mix with the growth medium of R. solani. After in vitro-validation, both strains were evaluated under greenhouse and the results concluded that strain MB101 had significant biocontrol potential as compared to MB14. Strain MB101 was enhanced the plant height, biomass and chlorophyll content of tomato plant through a higher degree of root colonization. In field trials, strain MB101 showed higher lessening in root rot symptoms with significant fruit yield as compare to strain MB14 and infected control. Next to the field study, the presence of four antibiotic genes (srfAA, fenD, ituC, and bmyB) also concluded the antifungal nature of both Bacillus strains. Phylogenetic analysis of protein sequences revealed a close relatedness of three genes (srfAA, fenD, and ituC) with earlier reported sequences of B. subtilis and B. amyloliquefaciens. However, bmyB showed heterogeneity in among both strains (MB14 and MB101) and it may be concluded that higher degree of antagonism, root colonization and different antibiotic producing genes may play an important role in biocontrol mechanism of strain MB101. PMID:24277414
Induction of defense response against Rhizoctonia solani in cucumber plants by endophytic bacterium Bacillus thuringiensis GS1.
Seo, Dong-Jun; Nguyen, Dang-Minh-Chanh; Song, Yong-Su; Jung, Woo-Jin
An endophytic bacterium, Bacillus thuringiensis GS1, was isolated from bracken (Pteridium aquilinum) and found to have maximal production of chitinase (4.3 units/ml) at 5 days after culture. This study investigated the ability of B. thuringiensis GS1 to induce resistance to Rhizoctonia solani KACC 40111 (RS) in cucumber plants. Chitinase activity was greatest in RS-treated plants at 4 days. beta-1,3- Glucanase activity was highest in GS1-treated plants at 5 days. Guaiacol peroxidase (GPOD) activity increased continuously in all treated plants for 5 days. Ascorbate peroxidase (APX) activity in RS-treated plants was increased 1.5-fold compared with the control at 4 days. Polyphenol oxidase (PPO) activity in RS-treated plants was increased 1.5-fold compared with the control at 3 days. At 5 days after treatment, activity staining revealed three bands with chitinase activity (Ch1, Ch2, and Ch3) on SDSPAGE of cucumber plants treated with GS1+RS, whereas only one band was observed for RS-treated plants (Ch2). One GPOD isozyme (Gp1) was also observed in response to treatment with RS and GS1+RS at 4 days. One APX band (Ap2) was present on the native-PAGE gel of the control, and GS1- and GS1+RS-treated plants at 1 day. PPO bands (Po1 and Po2) from RS- and GS1+RS-treated plants were stronger than in the control and GS1-treated plants upon native-PAGE at 5 days. Taken together, these results indicate that the induction of PR proteins and defense-related enzymes by B. thuringiensis GS1 might have suppressed the damping-off caused by R. solani KACC 40111 in cucumber plants. PMID:22450798
Effect of timing of glyphosate application to a winter wheat cover crop on stunting of spring-sown onions caused by Rhizoctonia spp. in the Columbia Basin of Washington, 2012.
Technology Transfer Automated Retrieval System (TEKTRAN)
The development of patches of stunted onion plants caused by Rhizoctonia spp. is an emerging problem in onion bulb crops planted in the semi-arid Columbia Basin of Oregon and Washington following winter cereal cover crops. Cereals such as winter wheat are used as cover crops to protect onion seedlin...
The Mechanism of Antifungal Action of a New Polyene Macrolide Antibiotic Antifungalmycin 702 from Streptomyces padanus JAU4234 on the Rice Sheath Blight Pathogen Rhizoctonia solani
Xiong, Zhi-Qiang; Tu, Xiao-Rong; Wei, Sai-Jin; Huang, Lin; Li, Xun-Hang; Lu, Hui; Tu, Guo-Quan
Antifungalmycin 702, a new polyene macrolide antibiotic produced by Streptomycespadanus JAU4234, has a broad antifungal activity and may have potential future agricultural and/or clinical applications. However, the mechanism of antifungal action of antifungalmycin 702 remains unknown. Antifungalmycin 702 strongly inhibited mycelial growth and sclerotia formation/germination of Rhizoctonia solani. When treated with antifungalmycin 702, the hyphae morphology of R. solani became more irregular. The membrane and the cellular organelles were disrupted and there were many vacuoles in the cellular space. The lesion in the plasma membrane was detected through the increase of membrane permeability, lipid peroxidation and leakage of cell constituents. In summary, antifungalmycin 702 may exert its antifungal activity against R. solani by changing the structure of cell membranes and the cytoskeleton and interacting with the organelles. PMID:23951364
Enzyme Diffusion from Trichoderma atroviride (= T. harzianum P1) to Rhizoctonia solani Is a Prerequisite for Triggering of Trichoderma ech42 Gene Expression before Mycoparasitic Contact
Kullnig, Cornelia; Mach, Robert L.; Lorito, Matteo; Kubicek, Christian P.
A plate confrontation experiment is commonly used to study the mechanism by which Trichoderma spp. antagonize and parasitize other fungi. Previous work with chitinase gene expression (ech42) during the precontact period of this process in which cellophane and dialysis membranes separated Trichoderma harzianum and its host Rhizoctonia solani resulted in essentially opposite results. Here, we show that cellophane membranes are permeable to proteins up to at least 90 kDa in size but that dialysis membranes are not. ech42 was expressed during the precontact stage of the confrontation between Trichoderma atroviride and its host only if the cellophane was placed between the two fungi. These results are consistent with enzyme diffusion from T. atroviride to R. solani generating the trigger of ech42 gene expression. PMID:10788407
Integrated effect of microbial antagonist, organic amendment and fungicide in controlling seedling mortality (Rhizoctonia solani) and improving yield in pea (Pisum sativum L.).
Akhter, Wasira; Bhuiyan, Mohamed Khurshed Alam; Sultana, Farjana; Hossain, Mohamed Motaher
The study evaluated the comparative performance of a few microbial antagonists, organic amendments and fungicides and their integration for the management of seedling mortality (Rhizoctonia solani Kühn) and yield improvement in pea (Pisum sativum L.). Before setting the experiment in field microplots, a series of in vitro and in vivo experiments were conducted to select a virulent isolate of R. solani, an effective antagonistic isolate of Trichoderma harzianum, a fungitoxic organic amendment and an appropriate fungicide. A greenhouse pathogenicity test compared differences in seedling mortality in pea inoculated by four isolates of R. solani and identified the isolate RS10 as the most virulent one. Among the 20 isolates screened in dual culture assay on PDA, T. harzianum isolate T-3 was found to show the highest (77.22%) inhibition of the radial growth of R. solani. A complete inhibition (100.00%) of colony growth of R. solani was observed when fungicide Bavistin 50 WP and Provax-200 at the rate of 100 and 250 ppm, respectively, were used, while Provax-200 was found to be highly compatible with T. harzianum. Mustard oilcake gave maximum inhibition (60.28%) of the radial growth of R. solani at all ratios, followed by sesame oilcake and tea waste. Integration of soil treatment with T. harzianum isolate T-3 and mustard oilcake and seed treatment with Provax-200 appeared to be significantly superior in reducing seedling mortality and improving seed yield in pea in comparison to any single or dual application of them in the experimental field. The research results will help growers develop integrated disease management strategies for the control of Rhizoctonia disease in pea. The research results show the need for an integrating selective microbial antagonist, organic amendment and fungicide to achieve appropriate management of seedling mortality (R. solani) and increase of seed yield in pea. PMID:25528673
Production of protein by fungi from agricultural wastes. II. Effect of carbon/nitrogen ratio on the efficiency of substrate utilization and protein production by Rhizoctonia melongina, Pleurotus ostreatus, and Coprinus aratus.
Jauhri, K S; Sen, A
An attempt was made to standardize the C/N ratio at which maximum protein production may be achieved by Rhizoctonia melongina, Pleurotus ostreatus, and Coprinus aratus, using sugarcane bagasse for the former two and wheat straw for the latter in the liquid medium. Three different ways of changing the C/N ratios were tried. The optimum levels of carbon and nitrogen required for the best yield, substrate utilization, and protein production efficiency were worked out. PMID:571180
A One-Step, Immunochromatographic Lateral Flow Device Specific to Rhizoctonia solani and Certain Related Species, and Its Use to Detect and Quantify R. solani in Soil.
Thornton, Christopher R; Groenhof, Andrew C; Forrest, Robert; Lamotte, Richard
ABSTRACT A murine hybridoma cell line GD2 secreting an immunoglobulin (Ig)M monoclonal antibody (MAb) was produced against surface antigens from an anastomosis group (AG) 4 isolate of Rhizoctonia solani (teleomorph: Thanatephorus cucumeris). Ascites were produced in mice using GD2 hybridoma cells and used to develop a rapid immunochromatographic lateral flow device (LFD) for the detection of antigens from R. solani and certain related Rhizoctonia spp. The LFD was tested for specificity against surface antigens from related and unrelated soil fungi. Antigens from representative isolates of R. solani AGs 1, 2-1, 2-3, 2-t, 3, 4, 5, 6, 7, 8, 9, 10, 11, and BI gave a positive response in LFD tests, as did antigens from Thanatephorus orchidicola, T. praticola, R. fragariae (teleomorph: Ceratorhiza fragariae), Ceratorhiza goodyerae-repentis, Ceratobasidium cornigerum, and binucleate AGE. Antigens from R. solani AGs 2-2, 2-2IIIB, and 2-2IV and from the related fungi R. carotae, R. cerealis (teleomorph: Ceratobasium cereale), R. crocorum (teleomorph: Helicobasidium brebissonii), R. oryzae (teleomorph Waitea circinata), and R. zeae gave negative responses, as did antigens from a range of unrelated fungi and oomycetes including Fusarium, Gliocladium, Trichoderma, Pythium, and Phytophthora spp. The usefulness of the LFD to detect R. solani was demonstrated in soils naturally infested with R. solani AG3. There was close agreement between results of LFD tests and conventional plate enrichment tests employing selective medium. The specificity of the technique was confirmed by polymerase chain reaction PCR using R. solani AG3-specific primers and by analyses based on sequences of the internal transcribed spacer (ITS)1-5.8S-ITS2 rRNA-encoding regions of unrelated fungi recovered from soil samples. The LFD was used to quantify R. solani AG4 in artificially infested soil samples (chopped potato soil inoculum). Estimates of CFU per gram of soil were derived using a most-probable number technique, which was based on the presence or absence of a detectable signal in the LFD. Estimates of CFU obtained in LFD tests and those obtained in a plate-trapped antigen enzyme-linked immunosorbent assay incorporating MAb GD2 were identical (449 CFU g(-1) of soil). PMID:18943976
Distinctively variable sequence-based nuclear DNA markers for multilocus phylogeography of the soybean- and rice-infecting fungal pathogen Rhizoctonia solani AG-1 IA
A series of multilocus sequence-based nuclear DNA markers was developed to infer the phylogeographical history of the Basidiomycetous fungal pathogen Rhizoctonia solani AG-1 IA infecting rice and soybean worldwide. The strategy was based on sequencing of cloned genomic DNA fragments (previously used as RFLP probes) and subsequent screening of fungal isolates to detect single nucleotide polymorphisms (SNPs). Ten primer pairs were designed based on these sequences, which resulted in PCR amplification of 200-320 bp size products and polymorphic sequences in all markers analyzed. By direct sequencing we identified both homokaryon and heterokaryon (i.e. dikaryon) isolates at each marker. Cloning the PCR products effectively estimated the allelic phase from heterokaryotic isolates. Information content varied among markers from 0.5 to 5.9 mutations per 100 bp. Thus, the former RFLP codominant probes were successfully converted into six distinctively variable sequence-based nuclear DNA markers. Rather than discarding low polymorphism loci, the combination of these distinctively variable anonymous nuclear markers would constitute an asset for the unbiased estimate of the phylogeographical parameters such as population sizes and divergent times, providing a more reliable species history that shaped the current population structure of R. solani AG-1 IA. PMID:21637462
Bacillomycin L and surfactin contribute synergistically to the phenotypic features of Bacillus subtilis 916 and the biocontrol of rice sheath blight induced by Rhizoctonia solani.
Luo, Chuping; Zhou, Huafei; Zou, Jincheng; Wang, Xiaoyu; Zhang, Rongsheng; Xiang, Yaping; Chen, Zhiyi
The antagonistic activity of lipopeptides in Bacillus subtilis 916 has been well documented, yet relatively little is known about their mechanism in biofilm formation and environmental colonization. This study sought to examine the interaction of B. subtilis 916 on Rhizoctonia solani-infected rice sheath to elucidate the mechanism of colonization on plant leaves. Results showed that the mutants ?bac, ?srf, and ?srf?+?bac of B. subtilis 916, deficient in bacillomycin L and surfactin production, respectively, not only altered colony morphology but also changed swarming motility, reduced antagonistic activity, and decreased biofilm formation. In particular, biofilm formation in mutant ?bac, not ?srf or ?srf?+?bac, were restored with addition of surfactin and bacillomycin L at 10 and 50 ?g/mL, respectively. Moreover, surfactin and bacillomycin L were able to restore or enhance swarming motility in the corresponding mutants at 10 ?g/mL, respectively. With the aid of green fluorescent protein tagging, it was demonstrated that B. subtilis 916 formed a robust biofilm on the rice sheath blight lesion and colonized well on R. solani-infected rice sheath, while its corresponding mutants performed poorly. These observations also correlated with the rice cultivar pot experiments, in which B. subtilis 916 exhibited greater biocontrol than its mutants. Our results suggest that surfactin and bacillomycin L contribute differently but synergistically to the biocontrol of rice sheath blight in B. subtilis 916 through its antifungal activity, biofilm formation, and colonization. PMID:25398282
Characterization of genes involved in biosynthesis of a novel antibiotic from Burkholderia cepacia BC11 and their role in biological control of Rhizoctonia solani
Kang, Y.; Carlson, R.; Tharpe, W.; Schell, M.A. [Univ. of Georgia, Athens, GA (United States)
Genetic manipulation of fluorescent pseudomonads has provided major insight into their production of antifungal molecules and their role in biological control of plant disease. Burkholderia cepacia also produces antifungal activities, but its biological control activity is much less well characterized, in part due to difficulties in applying genetic tools. Here the authors report genetic and biochemical characterization of a soil isolate of B. cepacia relating to its production of an unusual antibiotic that is very active against a variety of soil fungi. Purification and preliminary structural analyses suggest that this antibiotic (called AFC-BC11) is a novel lipopeptide associated largely with the cell membrane. Analysis of conditions for optimal production of AFC-BC11 indicated stringent environmental regulation of its synthesis. Furthermore, the authors show that production of AFC-BC11 is largely responsible for the ability of B. cepacia BC11 to effectively control the damping-Off of cotton caused by the fungal pathogen Rhizoctonia solani in a gnotobiotic system. Using Tn5 mutagenesis, they identified, cloned, and characterized a region of the genome of strain BC11 that is required for production of this antifungal metabolite. DNA sequence analysis suggested that this region encodes proteins directly involved in the production of a nonribosomally synthesized lipopeptide.
Liquid culture production of microsclerotia and submerged conidia by Trichoderma harzianum active against damping-off disease caused by Rhizoctonia solani.
Kobori, Nilce N; Mascarin, Gabriel M; Jackson, Mark A; Schisler, David A
Media and culturing protocols were identified that supported the formation of submerged conidia and microsclerotia (MS) by Trichoderma harzianum Rifai strain T-22 using liquid culture fermentation. Liquid media with a higher carbon concentration (36 g L(-1)) promoted MS formation at all C:N ratios tested. Hyphae aggregated to form MS after 2 d growth and after 7 d MS were fully melanized. This is the first report of MS formation by T. harzianum or any species of Trichoderma. Furthermore, submerged conidia formation was induced by liquid culture media, but yields, desiccation tolerance, and storage stability varied with C:N ratio and carbon rate. Air-dried MS granules (<4% moisture) retained excellent shelf life under cool and unrefrigerated storage conditions with no loss in conidial production. A low-cost complex nitrogen source based on cottonseed flour effectively supported high MS yields. Amending potting mix with dried MS formulations reduced or eliminated damping-off of melon seedlings caused by Rhizoctonia solani. Together, the results provide insights into the liquid culture production, stabilization process, and bioefficacy of the hitherto unreported MS of T. harzianum as a potential biofungicide for use in integrated management programs against soilborne diseases. PMID:25813507
Transcriptome analysis of the phytopathogenic fungus Rhizoctonia solani AG1-IB 7/3/14 applying high-throughput sequencing of expressed sequence tags (ESTs).
Wibberg, Daniel; Jelonek, Lukas; Rupp, Oliver; Kröber, Magdalena; Goesmann, Alexander; Grosch, Rita; Pühler, Alfred; Schlüter, Andreas
Rhizoctonia solani is a soil-borne plant pathogenic fungus of the phylum Basidiomycota. It affects a wide range of agriculturally important crops and hence is responsible for economically relevant crop losses. Transcriptome analysis of the bottom rot pathogen R. solani AG1-1B (isolate 7/3/14) by applying high-throughput sequencing and bioinformatics methods addressing Expressed Sequence Tag (EST) data interpretation provided new insights in expressed genes of this fungus. Two normalized cDNA libraries representing different cultivation conditions of the fungus were sequenced on the 454 FLX (Roche) system. Subsequent to cDNA sequence assembly and quality control, ESTs were analysed applying advanced bioinformatics methods. More than 14?000 transcript isoforms originating from approximately 10?000 predictable R. solani AG1-IB 7/3/14 genes are represented in each dataset. Comparative analyses revealed several differentially expressed genes depending on the growth conditions applied. Determinants with predicted functions in recognition processes between the fungus and the host plant were identified. Moreover, many R. solani AG1-IB ESTs were predicted to encode putative cellulose, pectin, and lignin degrading enzymes. Furthermore, genes playing a possible role in mitogen-activated protein (MAP) kinase cascades, 4-aminobutyric acid (GABA) metabolism, melanin synthesis, plant defence antagonism, phytotoxin, and mycotoxin synthesis were detected. PMID:25209639
Compositional variability and antifungal potentials of ocimum basilicum, O. tenuiflorum, O. gratissimum and O. kilimandscharicum essential oils against Rhizoctonia solani and Choanephora cucurbitarum.
Padalia, Rajendra C; Verma, Ram S; Chauhan, Amit; Goswami, Prakash; Chanotiya, Chandan S; Saroj, Arvind; Samad, Abdul; Khaliq, Abdul
The composition of hydrodistilled essential oils of Ocimum basilicum L. (four chemovariants), O. tenuiflorum L., O. gratissimum L., and O. kilimandscharicum Guerke were analyzed and compared by using capillary gas chromatography (GC/FID) and GC-mass spectrometry (GC/MS). Phenyl propanoids (upto 87.0%) and monoterpenoids (upto 83.3%) were prevalent constituents distributed in the studied Ocimum taxa. The major constituents of the four distinct chemovariants of O. basilicum were methyl chavicol (86.3%), methyl chavicol (61.5%)/linalool (28.6%), citral (65.9%); and linalool (36.1%)/citral (28.8%). Eugenol (66.5% and 78.0%) was the major constituent of O. tenuiflorum and O. gratissimum. Eugenol (34.0%), ?-bisabolene (15.4%), (E)-?-bisabolene (10.9%), methyl chavicol (10.2%) and 1,8-cineole (8.2%) were the major constituents of O. kilimandscharicum. In order to explore the potential for industrial use, the extracted essential oils were assessed for their antifungal potential through poison food technique against two phytopathogens, Rhizoctonia solani and Choanephora cucurbitarum, which cause root and wet rot diseases in various crops. O. tenuiflorum, O. gratissimum, and O. kilimandscharicum exhibited complete growth inhibition against R. solani and C. cucurbitarum after 24 and 48 h of treatment. O. basilicum chemotypes showed variable levels of growth inhibition (63.0%-100%) against these two phytopathogens. PMID:25522548
Chitinolytic Streptomyces vinaceusdrappus S5MW2 isolated from Chilika lake, India enhances plant growth and biocontrol efficacy through chitin supplementation against Rhizoctonia solani.
Yandigeri, Mahesh S; Malviya, Nityanand; Solanki, Manoj Kumar; Shrivastava, Pooja; Sivakumar, G
A chitinolytic actinomycete Streptomyces vinaceusdrappus S5MW2 was isolated from water sample of Chilika lake, India and identified using 16S rRNA gene sequencing. It showed in vitro antifungal activity against the sclerotia producing pathogen Rhizoctonia solani in a dual culture assay and by chitinase enzyme production in a chitin supplemented minimal broth. Moreover, isolate S5MW2 was further characterized for biocontrol (BC) and plant growth promoting features in a greenhouse experiment with or without colloidal chitin (CC). Results of greenhouse experiment showed that CC supplementation with S5MW2 showed a significant growth of tomato plants and superior disease reduction as compared to untreated control and without CC treated plants. Moreover, higher accumulation of chitinase also recovered in the CC supplemented plants. Significant effect of CC also concurred with the Analysis of Variance of greenhouse parameters. These results show that the a marine antagonist S5MW2 has BC efficiency against R. solani and chitinase enzyme played important role in plant resistance. PMID:25982747
Analysis of Phaseolus vulgaris response to its association with Trichoderma harzianum (ALL-42) in the presence or absence of the phytopathogenic fungi Rhizoctonia solani and Fusarium solani.
Pereira, Jackeline L; Queiroz, Rayner M L; Charneau, Sébastien O; Felix, Carlos R; Ricart, Carlos A O; da Silva, Francilene Lopes; Steindorff, Andrei Stecca; Ulhoa, Cirano J; Noronha, Eliane F
The present study was carried out to evaluate the ability of Trichoderma harzianum (ALL 42-isolated from Brazilian Cerrado soil) to promote common bean growth and to modulate its metabolism and defense response in the presence or absence of the phytopathogenic fungi Rhizoctonia solani and Fusarium solani using a proteomic approach. T. harzianum was able to promote common bean plants growth as shown by the increase in root/foliar areas and by size in comparison to plants grown in its absence. The interaction was shown to modulate the expression of defense-related genes (Glu1, pod3 and lox1) in roots of P. vulgaris. Proteomic maps constructed using roots and leaves of plants challenged or unchallenged by T. harzianum and phytopathogenic fungi showed differences. Reference gels presented differences in spot distribution (absence/presence) and relative volumes of common spots (up or down-regulation). Differential spots were identified by peptide fingerprinting MALDI-TOF mass spectrometry. A total of 48 identified spots (19 for leaves and 29 for roots) were grouped into protein functional classes. For leaves, 33%, 22% and 11% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively. For roots, 17.2%, 24.1% and 10.3% of the identified proteins were categorized as pertaining to the groups: metabolism, defense response and oxidative stress response, respectively. PMID:24878929
Pelargonium graveolens L'Her. and Artemisia arborescens L. essential oils: chemical composition, antifungal activity against Rhizoctonia solani and insecticidal activity against Rhysopertha dominica.
Bouzenna, Hafsia; Krichen, Lamia
The chemical composition of the Pelargonium graveolens essential oil allowed the identification of 15 compounds (93.86% of the total essential oil). The major fractions were citronellol (35%) and geraniol (28.8%). The chemical composition of the Artemisia arborescens essential oil revealed twenty-one compounds representing 93.57% of the total essential oil. The main compounds were chamazulene (31.9%) and camphor (25.8%). The insecticidal effects were tested towards the insect Rhysopertha dominica. Results revealed that these two essential oils were highly effective against R. dominica at the dose of 50?µL on Petri dish of 8.5?cm of diameter. The antifungal activity was evaluated against Rhizoctonia solani and results showed that both of the essential oils were highly active at a dose of 12.5?µL/20?mL of PDA. Moreover, the inhibitory effect of P. graveolens essential oil was evidenced as stronger than that of the A. arborescens oil for all the tested doses. PMID:22840199
CD45-mediated signaling pathway is involved in Rhizoctonia bataticola lectin (RBL)-induced proliferation and Th1/Th2 cytokine secretion in human PBMC
Pujari, Radha [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India)] [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India); Eligar, Sachin M. [Department of Biochemistry, Karnatak University, Dharwad, 580003 Karnataka (India)] [Department of Biochemistry, Karnatak University, Dharwad, 580003 Karnataka (India); Kumar, Natesh [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India)] [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India); Nagre, Nagaraja N.; Inamdar, Shashikala R.; Swamy, Bale M. [Department of Biochemistry, Karnatak University, Dharwad, 580003 Karnataka (India)] [Department of Biochemistry, Karnatak University, Dharwad, 580003 Karnataka (India); Shastry, Padma, E-mail: email@example.com [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India)] [National Centre for Cell Science, Ganeshkhind, Pune 411007 (India)
Highlights: Black-Right-Pointing-Pointer RBL, a potent mitogenic and complex N-glycan specific lectin binds to CD45 on PBMC. Black-Right-Pointing-Pointer RBL triggers CD45-mediated signaling involved in activation of p38MAPK and STAT-5. Black-Right-Pointing-Pointer Inhibition of CD45 PTPase signaling blocks RBL-induced ZAP70 phosphorylation. Black-Right-Pointing-Pointer RBL-CD45 mediated signaling is crucial for RBL-induced immunodulatory activities. -- Abstract: We earlier reported the mitogenic and immunostimulatory activities of Rhizoctonia bataticola lectin (RBL), purified from phytopathogenic fungus R. bataticola in human PBMC. The lectin demonstrates specificity towards glycoproteins containing complex N-glycans. Since CD45-protein tyrosine phosphatase that abundantly expresses N-glycans is important in T-cell signaling, the study aimed to investigate the involvement of CD45 in the immunomodulatory activities of RBL. Flowcytometry and confocal microscopy studies revealed that RBL exhibited binding to PBMC and colocalized with CD45. The binding was comparable in cells expressing different CD45 isoforms-RA, -RB and -RO. CD45 blocking antibody reduced the binding and proliferation of PBMC induced by RBL. CD45-PTPase inhibitor dephostatin inhibited RBL-induced proliferation, expression of CD25 and pZAP-70. RBL-induced secretion of Th1/Th2 cytokines were significantly inhibited in presence of dephostatin. Also, dephostatin blocked phosphorylation of p38MAPK and STAT-5 that was crucial for the biological functions of RBL. The study demonstrates the involvement of CD45-mediated signaling in RBL-induced PBMC proliferation and Th1/Th2 cytokine secretion through activation of p38MAPK and STAT-5.
The wheat ethylene response factor transcription factor pathogen-induced ERF1 mediates host responses to both the necrotrophic pathogen Rhizoctonia cerealis and freezing stresses.
Zhu, Xiuliang; Qi, Lin; Liu, Xin; Cai, Shibin; Xu, Huijun; Huang, Rongfeng; Li, Jiarui; Wei, Xuening; Zhang, Zengyan
Sharp eyespot disease (primarily caused by the pathogen Rhizoctonia cerealis) and freezing stress are important yield limitations for the production of wheat (Triticum aestivum). Here, we report new insights into the function and underlying mechanisms of an ethylene response factor (ERF) in wheat, Pathogen-Induced ERF1 (TaPIE1), in host responses to R. cerealis and freezing stresses. TaPIE1-overexpressing transgenic wheat exhibited significantly enhanced resistance to both R. cerealis and freezing stresses, whereas TaPIE1-underexpressing wheat plants were more susceptible to both stresses relative to control plants. Following both stress treatments, electrolyte leakage and hydrogen peroxide content were significantly reduced, and both proline and soluble sugar contents were elevated in TaPIE1-overexpressing wheat, whereas these physiological traits in TaPIE1-underexpressing wheat exhibited the opposite trend. Microarray and quantitative reverse transcription-polymerase chain reaction analyses of TaPIE1-overexpressing and -underexpressing wheat plants indicated that TaPIE1 activated a subset of defense- and stress-related genes. Assays of DNA binding by electrophoretic mobility shift and transient expression in tobacco (Nicotiana tabacum) showed that the GCC boxes in the promoters of TaPIE1-activated genes were essential for transactivation by TaPIE1. The transactivation activity of TaPIE1 and the expression of TaPIE1-activated defense- and stress-related genes were significantly elevated following R. cerealis, freezing, and exogenous ethylene treatments. TaPIE1-mediated responses to R. cerealis and freezing were positively modulated by ethylene biosynthesis. These data suggest that TaPIE1 positively regulates the defense responses to R. cerealis and freezing stresses by activating defense- and stress-related genes downstream of the ethylene signaling pathway and by modulating related physiological traits in wheat. PMID:24424323
Suppression subtractive hybridization and comparative expression of a pore-forming toxin and glycosyl hydrolase genes in Rhizoctonia solani during potato sprout infection.
Chamoun, Rony; Samsatly, Jamil; Pakala, Suman B; Cubeta, Marc A; Jabaji, Suha
Rhizoctonia solani is a plant pathogenic fungus that causes black scurf on tubers and stem and stolon canker on underground parts of potato plant. Early in the season, the fungus attacks germinating sprouts underground before they emerge from the soil. Damage at this stage results in delayed emergence of weakened plants with poor and uneven stands. The mechanism underlying this phenomenon has been investigated in this study by coupling a cDNA-suppression subtractive hybridization (SSH) library to differential screening to identify transcripts of R. solani that are down-regulated during infection of potato sprouts. We report on the identification of 33 unique genes with functions related to carbohydrate binding, vitamin synthesis, pathogenicity, translation, ATP and nucleic acid binding and other categories. RACE-PCR was used to clone and characterize the first full-length cDNA clones, RSENDO1 and RSGLYC1 that encode for an eukaryotic delta-endotoxin CytB protein and an intracellular glycosyl hydrolase, respectively. Quantitative real-time PCR revealed the down-regulation of RSENDO1 during infection of potato sprouts and the up-regulation of RSGLYC1 when the fungus was grown on a cellulose-based nutrient medium. In contrast, additional experiments have highlighted the down-regulation of RSENDO1 when R. solani was co-cultured with the mycoparasite Stachybotrys elegans and the bacterial antagonist Bacillus subtilis B26. These results advance our understanding of R. solani-potato interaction in subterranean parts of the plant. Such approaches could be considered in building an efficient integrated potato disease management program. PMID:25472038
High-resolution mapping of Rsn1, a locus controlling sensitivity of rice to a necrosis-inducing phytotoxin from Rhizoctonia solani AG1-IA.
Costanzo, Stefano; Jackson, Aaron K; Brooks, Steven A
Rhizoctonia solani is a necrotrophic fungal pathogen that causes disease on many crop-plant species. Anastomosis group 1-IA is the causal agent of sheath blight of rice (Oryza sativa L.), one of the most important rice diseases worldwide. R. solani AG1-IA produces a necrosis-inducing phytotoxin and rice cultivar's sensitivity to the toxin correlates with disease susceptibility. Unlike genetic analyses of sheath blight resistance where resistance loci have been reported as quantitative trait loci, phytotoxin sensitivity is inherited as a Mendelian trait that permits high-resolution mapping of the sensitivity genes. An F(2) mapping population derived from parent cultivars 'Cypress' (toxin sensitive) and 'Jasmine 85' (toxin insensitive) was used to map Rsn1, the necrosis-inducing locus. Initial mapping based on 176 F(2) progeny and 69 simple sequence repeat (SSR) markers located Rsn1 on the long arm of chromosome 7, with tight linkage to SSR marker RM418. A high-resolution genetic map of the region was subsequently developed using a total of 1,043 F(2) progeny, and Rsn1 was mapped to a 0.7 cM interval flanked by markers NM590 and RM418. Analysis of the corresponding 29 Kb genomic sequences from reference cultivars 'Nipponbare' and '93-11' revealed the presence of four putative genes within the interval. Two are expressed cytokinin-O-glucosyltransferases, which fit an apoptotic pathway model of toxin activity, and are individually being investigated further as potential candidates for Rsn1. PMID:21424397
Phylogeography of the Solanaceae-infecting Basidiomycota fungus Rhizoctonia solani AG-3 based on sequence analysis of two nuclear DNA loci
Ceresini, Paulo C; Shew, H David; James, Timothy Y; Vilgalys, Rytas J; Cubeta, Marc A
Background The soil fungus Rhizoctonia solani anastomosis group 3 (AG-3) is an important pathogen of cultivated plants in the family Solanaceae. Isolates of R. solani AG-3 are taxonomically related based on the composition of cellular fatty acids, phylogenetic analysis of nuclear ribosomal DNA (rDNA) and beta-tubulin gene sequences, and somatic hyphal interactions. Despite the close genetic relationship among isolates of R. solani AG-3, field populations from potato and tobacco exhibit comparative differences in their disease biology, dispersal ecology, host specialization, genetic diversity and population structure. However, little information is available on how field populations of R. solani AG-3 on potato and tobacco are shaped by population genetic processes. In this study, two field populations of R. solani AG-3 from potato in North Carolina (NC) and the Northern USA; and two field populations from tobacco in NC and Southern Brazil were examined using sequence analysis of two cloned regions of nuclear DNA (pP42F and pP89). Results Populations of R. solani AG-3 from potato were genetically diverse with a high frequency of heterozygosity, while limited or no genetic diversity was observed within the highly homozygous tobacco populations from NC and Brazil. Except for one isolate (TBR24), all NC and Brazilian isolates from tobacco shared the same alleles. No alleles were shared between potato and tobacco populations of R. solani AG-3, indicating no gene flow between them. To infer historical events that influenced current geographical patterns observed for populations of R. solani AG-3 from potato, we performed an analysis of molecular variance (AMOVA) and a nested clade analysis (NCA). Population differentiation was detected for locus pP89 (?ST = 0.257, significant at P < 0.05) but not for locus pP42F (?ST = 0.034, not significant). Results based on NCA of the pP89 locus suggest that historical restricted gene flow is a plausible explanation for the geographical association of clades. Coalescent-based simulations of genealogical relationships between populations of R. solani AG-3 from potato and tobacco were used to estimate the amount and directionality of historical migration patterns in time, and the ages of mutations of populations. Low rates of historical movement of genes were observed between the potato and tobacco populations of R. solani AG-3. Conclusion The two sisters populations of the basidiomycete fungus R. solani AG-3 from potato and tobacco represent two genetically distinct and historically divergent lineages that have probably evolved within the range of their particular related Solanaceae hosts as sympatric species. PMID:17854492
Effect of carbon and nitrogen sources on growth and biological efficacy of Pseudomonas fluorescens and Bacillus subtilis against Rhizoctonia solani, the causal agent of bean damping-off.
Peighamy-Ashnaei, S; Sharifi-Tehrani, A; Ahmadzadeh, M; Behboudi, K
One of the most important environmental factors that regulate the growth and antagonistic efficacy of biocontrol agents is the medium. The aim of this paper was to find the nitrogen and carbon sources that provide maximum biomass production of strains P-5 and P-6 (Pseudomonas fluorescens), B-3 and B-16 (Bacillus subtilis) and minimum cost of media, whilst maintaining biocontrol efficacy. All of the strains were grown in seven liquid media (pH=6.9) including: sucrose + yeast extract, molasses of sugar beet + yeast extract in 2:1 and 1:1 w/w ratios, molasses of sugar beet + urea, nutrient broth, molasses and malt extract, at an initial inoculation of 1 x 10(5) CFU ml(-1). Cells from over night cultures used to inoculate soil at 1 x 10(9) CFU cm(-3) soil. At the same time, fungal inoculum (infected millet seed with Rhizoctonia solani) was added to soil at the rate of 2 g kg(-1) soil. Results indicated that growth of P-6, B-3 and B-16 in molasses + yeast extract (1:1 w/w) medium was significantly higher than in the other media. Molasses + yeast extract (1:1 and 2:1 w/w) media supported rapid growth and high cell yields in P-5. In greenhouse condition, results indicated that the influence of the media on the biocontrol efficacy of P-5, P-6, B-3 and B-16 was the same and Pseudomonas fluorescens P-5 in molasses and malt extract media reduced the severity of disease up to 72.8 percent. On the other hand, there were observed significant differences on bean growth after one month in greenhouse. P-5 in molasses + yeast extract (1:1 w/w) medium had the most effects on bean growth promotion. In this study molasses media showed good yield efficacy in all of the strains. The high sucrose concentration in molasses justifies the high biomass in all of the strains. Also, the low cost of molasses allows its concentration to be increased in media. On the other hand, yeast extract was the best organic nitrogen source for antagonist bacteria but it is expensive for an industrial process. So it should be replaced by another industrial product instead of yeast extract, which confirm by an economic and technological study. The results obtained in this study could be used to provide a reliable basis to increase the population of biocontrol agents in fermentation process. PMID:18396833
Effects of damping-off caused by Rhizoctonia solani anastomosis group 2-1 on roots of wheat and oil seed rape quantified using X-ray Computed Tomography and real-time PCR
Sturrock, Craig J.; Woodhall, James; Brown, Matthew; Walker, Catherine; Mooney, Sacha J.; Ray, Rumiana V.
Rhizoctonia solani is a plant pathogenic fungus that causes significant establishment and yield losses to several important food crops globally. This is the first application of high resolution X-ray micro Computed Tomography (X-ray ?CT) and real-time PCR to study host–pathogen interactions in situ and elucidate the mechanism of Rhizoctonia damping-off disease over a 6-day period caused by R. solani, anastomosis group (AG) 2-1 in wheat (Triticum aestivum cv. Gallant) and oil seed rape (OSR, Brassica napus cv. Marinka). Temporal, non-destructive analysis of root system architectures was performed using RooTrak and validated by the destructive method of root washing. Disease was assessed visually and related to pathogen DNA quantification in soil using real-time PCR. R. solani AG2-1 at similar initial DNA concentrations in soil was capable of causing significant damage to the developing root systems of both wheat and OSR. Disease caused reductions in primary root number, root volume, root surface area, and convex hull which were affected less in the monocotyledonous host. Wheat was more tolerant to the pathogen, exhibited fewer symptoms and developed more complex root systems. In contrast, R. solani caused earlier damage and maceration of the taproot of the dicot, OSR. Disease severity was related to pathogen DNA accumulation in soil only for OSR, however, reductions in root traits were significantly associated with both disease and pathogen DNA. The method offers the first steps in advancing current understanding of soil-borne pathogen behavior in situ at the pore scale, which may lead to the development of mitigation measures to combat disease influence in the field.
Technology Transfer Automated Retrieval System (TEKTRAN)
In May 2001, severe stunting, lateral rot, and brown discoloration of taproots were observed in a field of direct-seed (no-till) pea (cv. Columbia) southeast of Lewiston, ID. The field had been previously cropped with direct-seeded spring barley. Roots were washed, plated on water agar containi...
Early steps of slaframine and swainsonine biogenesis in Rhizoctonia leguminicola
Wickwire, B.M.; Broquist, H.P.
Pipecolic acid (PIP), a precursor of slaframine (SF) and swainsonine (SW) in the fungus R. leguminicola, is thought to arise from L-lysine (LYS). The epsilon-N atom of LYS constitutes the N atom of PIP. Interest in these reactions arises in relation to mechanisms of regulation of SF and SW, and perhaps to piperidine alkaloid biogenesis in general. The authors have not been able to demonstrate an L-LYS oxidase, reaction A, in R. leguminicola. Rather when (U-/sup 14/C)-L-LYS was incubated with cell-free R. leguminicola extracts together with ..cap alpha..-ketoglutarate and NADH,H/sup +/ and subsequently deproteinized and chromatographed (HPLC), large amounts of saccharopine (SAC) together with small amounts of two other radioactive metabolites (II, III) were formed. Compound III is PIP. Metabolite II appears to be an intermediate between SAC and PIP. Growing cultures of R. leguminicola also accumulate SAC. Thus, SAC formed via the aminoadipate pathway of LYS biosynthesis may be at a branch point in the pathways for LYS and PIP biogenesis and be subject to enzymic regulation with subsequent accumulation following formation of LYS, SF, and SW.
Hyperparasites of Rhizoctonia solani in Dutch potato fields
G. Jager; A. Ten Hoopen; H. Velvis
Gliocladium roseum was found to be the most common and probably the most effective mycoparasite in potato fields in the northern parts of the Netherlands. It is able to parasitize and kill living hyphae at temperatures of 12°C and higher. Sclerotia ofR. solani are often infected and killed by this fungus under suitable conditions, i.e. at temperatures of 16°C and
www.ext.vt.edu Produced by Communications and Marketing, College of Agriculture and Life Sciences,
Liskiewicz, Maciej
XXXXXXXXXXXXXXXXXXXXXXXXX Rhizoctonia brown patch ·············XXXXXXXXXXXXXXXXXXXX········ Pythium blight outbreaks of Rhizoctonia brown patch often justify preventive fungicide applications before the symptoms
Volatiles of bacterial antagonists inhibit mycelial growth of the plant pathogen Rhizoctonia solani
Marco Kai; Uta Effmert; Gabriele Berg; Birgit Piechulla
Bacterial antagonists are bacteria that negatively affect the growth of other organisms. Many antagonists inhibit the growth\\u000a of fungi by various mechanisms, e.g., secretion of lytic enzymes, siderophores and antibiotics. Such inhibition of fungal\\u000a growth may indirectly support plant growth. Here, we demonstrate that small organic volatile compounds (VOCs) emitted from\\u000a bacterial antagonists negatively influence the mycelial growth of the
Control of Rhizoctonia solani in cotton by seed-coating with Trichoderma spp. spores
Yigal Elad; Avraham Kalfon; Ilan Chet
Summary Coating cotton seeds withTrichoderma spp. reduced the incidence of disease caused byR. solani by up to 83% in the greenhouse.T. hamatum was more efficient in disease control at 20°C, whileT. harzianum was superior at 27°C. Disease severity was reduced by 47–60% in two field experiments, showing no statistical difference from treatment with pentachloronitrobenzene.
Transgenic Plants with Enhanced Resistance to the Fungal Pathogen Rhizoctonia solani
Karen Broglie; Ilan Chet; Mark Holliday; Robert Cressman; Phyllis Biddle; Susan Knowlton; C. Jeffry Mauvais; Richard Broglie
The production of enzymes capable of degrading the cell walls of invading phytopathogenic fungi is an important component of the defense response of plants. The timing of this natural host defense mechanism was modified to produce fungal-resistant plants. Transgenic tobacco seedlings constitutively expressing a bean chitinase gene under control of the cauliflower mosaic virus 35S promoter showed an increased ability
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice (Oryza sativa L.) is considered a model crop plant due to its importance worldwide as a food source, a small diploid genome suitable for genetic and proteomic analyses, and completion of the rice genome sequence. The objective of our research was to utilize both proteomic and genetic approaches...
The Evaluation of High Tannin Cotton Lines for Resistance to Rhizoctonia solani and Pythium aphanidermatum
Kennett, Raymond Matthew
to the resistant control, Tamcot Sphinx (El-Zik and Thaxton, 1996). This resistance was not shown to be correlated with tannin content, though it is still unclear whether or not this lack of correlation is real or due to limitations in measuring tannin in infected...
Pathologie vgtale Intrt des racines transformes pour le maintien
Paris-Sud XI, Université de
, Phytophthora infestans et Rhizoctonia violacea. Sauf pour P lycopersici, la conservation sous azote liquide est phytopathologie est discuté. Pyrenochaeta lycopersici / Phytophthora infestans / Rhizoctonia violacea / tomate, Pyrenochaeta lycopersici (tab I), Phytophthora infestans (tab II) and Rhizoctonia violacea (tab III
Seasonal Activity of Turfgrass Pathogens in the Midwest
Holland, Jeffrey
(microdochium patch) Rhizoctonia cereale yellow patch Drechslera and Bipolaris spp. melting out Laetisaria fuciformis red thread Rhizoctonia solani large patch Limonomyces roseipellis pink patch Sclerotinia spot Drechslera and Bipolaris spp. leaf spot Rhizoctonia solani brown patch Pythium spp. Pythium blight
www.newphytologist.org 1 Blackwell Publishing LtdOxford, UKNPHNew Phytologist0028-646X The Authors (2007). Journal compilation New Phytologist (2007)232010.1111/j.1469-8137.2007.02320.xNovember 2007001???14???MethodsMethods Methods
Taylor, Lee
: Ceratobasidium, mycorrhiza, Orchidaceae, Rhizoctonia, ribosomal ITS sequence, Thanatephorus, Tomentella-genus Rhizoctonia (Burgeff, 1959; Hadley, 1982; Rasmussen, 1995). This genus includes fungi with perfect states). However, all recorded orchid- associated Rhizoctonia species belong to the Ceratobasidiaceae, Sebacinaceae
Determinants of survival over 7 years for a natural cohort of sugar maple seedlings in a northern hardwood forest
Battles, John
was high (71%), and the main damage agents were fungal infection (Rhizoctonia spp.) and caterpillar that damages seedlings. Key words: Geometridae, Hubbard Brook Experimental Forest, mortality, Rhizoctonia premičre saison et les principaux agents détériorateurs étaient les infections fongiques (Rhizoctonia spp
1020 www.newphytologist.org Blackwell Publishing LtdOxford, UKNPHNew Phytologist0028-646X The Authors (2007). Journal compilation New Phytologist (2007)232010.1111/j.1469-8137.2007.02320.xNovember 2007001020???1033???MethodsMethods Methods
Taylor, Lee
: Ceratobasidium, mycorrhiza, Orchidaceae, Rhizoctonia, ribosomal ITS sequence, Thanatephorus, Tomentella-genus Rhizoctonia (Burgeff, 1959; Hadley, 1982; Rasmussen, 1995). This genus includes fungi with perfect states). However, all recorded orchid- associated Rhizoctonia species belong to the Ceratobasidiaceae, Sebacinaceae
BIOSYNTHESIS O F S L A F R A M I N E . 4 more fully oxygenated) medium suppresses formation of
Walter, Peter
,3-Dioxooctahydroindolizine,and 1-Hydroxyoctahydroindolizine in Rhizoctonia leguminicolat E. C. Clevenstine, P. Walter, T. M Rhizoctonia leguminicola, were prepared and tested for bi- ological conversions. Ethyl pipecolylacetate
Ralits et perspectives de la lutte biologique contre les maladies des plantes (*)
Paris-Sud XI, Université de
, Sclerotinia, Protection croisée. Rhizoctonia, Verticillium ou autres parasites. En conjuguant l'action de control agents (such as Trichoderma ), attacks by Rhizoctonia, Sclerotium, Sclerotinia, Verticillium
2009 Virginia Polytechnic Institute and State University 2906-1298 Virginia Cooperative Extension programs and employment are open to all, regardless of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, o
Liskiewicz, Maciej
) strain T-22 (PlantshieldÔ). TH protects plant roots from pathogens such as Pythium, Rhizoctonia, Fusarium bacteria · Target Pathogens - Pythium, Rhizoctonia, Phytophthora, and Fusarium · Crops bedding plants
Technology Transfer Automated Retrieval System (TEKTRAN)
Both Quadris and Moncut 70 DF significantly increased seedling height and length of the first true leaf compared to the control treatment, although there was no significant difference between the in-furrow treatments. In-furrow application of these fungicides also reduced the percent infected crow...
Technology Transfer Automated Retrieval System (TEKTRAN)
Six different rotation crops (barley/clover, canola, green bean, rapeseed, soybean, and sweet corn) planted in 2-yr rotations with potato (and a continuous potato nonrotation control) were evaluated both with and without a fall cover crop of winter rye for their effects on the development of soilbor...
The role of an extracellular chitinase from Trichoderma virens Gv29-8 in the biocontrol of Rhizoctonia solani
Jong-Min Baek; Charles R. Howell; Charles M. Kenerley
The role of extracellular chitinase in the biocontrol activity of Trichoderma virens was examined using genetically manipulated strains of this fungus. The T. virens strains in which the chitinase gene (cht42) was disrupted (KO) or constitutively over-expressed (COE) were constructed through genetic transformation. The resulting\\u000a transformants were stable and showed patterns similar to the wild-type (WT) strain with respect to
Single Plant Selection as a Screening Method for Resistance to Rhizoctonia solani and Pythium ultimum in Cotton
Jones, Whitney M
resistant cotton germplasm was established at Texas A&M University AgriLife Research. Five germplasm families selected for elevated levels of condensed tannins were evaluated for resistance to R. solani and P. ultimum. Two generations of single plant...
First Report of Rhizoctonia spp. causing a root rot of the invasive rangeland weed Lepidium draba in North America.
Technology Transfer Automated Retrieval System (TEKTRAN)
The exotic, invasive perennial rangeland weed Lepidium draba spreads rapidly and reduces native species diversity. The extensive root system of L. draba constitutes 76% of plant biomass. Thus searches have been done for biocontrol agents that target root tissue or that may interact with a weevil, Ce...
The influence of cropping systems on inoculum density of Rhizoctonia solani and sheath blight of rice (Oryza sativa)
Belmar, Scott Bradley
in viability with time and the occurrence of a major epidemic of aerial web blight of soybeans in August 1983. A highly significant (9=0. 01) linear correlation was observed between number of sclerotia recovered and disease incidence (y = 0. 48 + 1. 26x...), where y equals percentage of diseased tillers at the panicle initiation growth stage of rice and x equals sclerotia recovered per kg soil. ACKNOWLEGMENTS I express my indebtedness to Drs. Roger Jones and James Starr, for their invaluable advice...
Preparation and characterization of nano-sized calcium carbonate as controlled release pesticide carrier for validamycin against Rhizoctonia solani
Kun Qian; Tianyu Shi; Tao Tang; Shaoliang Zhang; Xili Liu; Yongsong Cao
Nano-sized calcium carbonate (nano-CC) was studied in terms of acting as a carrier for a pesticide. Nano-CC was prepared by\\u000a reaction of calcium chloride and sodium carbonate by the reversed-phase microemulsion method and then loaded with the pesticide\\u000a validamycin. The resulting material was characterized by X-ray diffraction analysis and scanning electron microscopy. The\\u000a loading efficiency, sustained-release performance, germicidal efficacy, and
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice (Oryza sativa L.) is considered a model crop plant due to its importance worldwide as a food source, a small diploid genome suitable for genetic and proteomic analyses, and completion of the rice genome sequence. The objective of our research was to utilize both proteomic and genetic approaches...
Pathologie vgtale volution au champ de la croissance et laboration
Boyer, Edmond
de blé d'hiver, en fonction des attaques de Rhizoctonia cerealis P Lucas N Cavelier J Pierre G — Rhizoctonia cerealis, agent du rhizoctone des céréales, est susceptible d'attaquer la plante ŕ- ing on attacks by Rhizoctonia corealis. Rhizoctonia cerealis, causal agent of sharp-eyespot of cereals
MSU Extension Publication Archive Archive copy of publication, do not use for current recommendations. Up-to-date
. Rhizoctonia Brown Patch-Turf Tips Michigan State University Extension Service T. K. Danneberger, J. M. Vargas the publication. #12;Rhizoctonia Brown Patch T. K. Danneberger, J. M. Vargas,Jr.,D. L. Roberts,K. J.Kelly Rhizoctonia brown patch, caused by Rhizoctonia solani Kuhn, attacks all turfgrass species in Michigan
Distribution And Efficacy Of Drip-Applied Metam-Sodium Against The Survival Of Rhizoctonia Solani And Yellow Nutsedge In Plastic-Mulched Sandy Soil Beds
Technology Transfer Automated Retrieval System (TEKTRAN)
The effects of metam-sodium application rate on soil residence time, spatial and temporal distributions of methyl isothiocyanate and pest control efficacy were studied in a Georgia sandy soil. Metam-sodium 420 gL-1 SL was drip applied at rates of 147 and 295Lha-1 in plastic-mulched raised beds. Meth...
Efectividad Biológica de TCMTB para el Control de la Costra Negra Rhizoctonia solani Kühn de la Papa Solanum Tuberosum L., en la Región de León, Guanajuato, México
Luis Pérez Moreno; Fernando Javier; Cantú Galindo
During the 1988 summer-fall growing cycle in the Mexican region of Leon, Guanajuato the fungicide 2-(Thiocyanomethylthio) benzothiazole (TCMTB) was evaluated applying it at the rate of 6, 8 and 10 liters per hectare for the control of soil borne Black Scurf R. solani. A randomized block design with four reps was used. An evaluation was made of the following: emerged
Technology Transfer Automated Retrieval System (TEKTRAN)
In-furrow of application of nitrogen significantly reduced the seminal root rot rating and increased seedling height, length of the first leaf, and the number of seminal and crown roots compared to the control treatment. Plants from the tillage + Nitropak treatment had the lowest seminal root rot ra...
Registration of FC723 and FC723 CMS Monogerm Sugarbeet Germplasm Resistant to Rhizoctonia Root Rot and moderately Resistant to Cercospora Leaf Spot.
Technology Transfer Automated Retrieval System (TEKTRAN)
Sugarbeet (Beta vulgaris L.) germplasms FC723 and FC723CMS (Reg. nos. GP-GP-, PI 639917 and PI 639918, respectively) were developed by the USDA-ARS, at Fort Collins, Colorado, in cooperation with the Beet Sugar Development Foundation, Denver, CO. FC723 has good resistance to root-rotting strains (A...
The Evaluation of High Tannin Cotton Lines and Their Use in Breeding for Resistance to Xanthomonas axonopodis pv. malvacearum, Pythium aphanidermatum and Rhizoctonia solani
Kennett, Raymond
and diallel analysis. The importance of tannin content in conferring resistance to X. axonopodis and R. solani was also measured. Four high tannin lines were found to be not different from Tamcot Sphinx in their resistance to Xam. Generation means analysis...
Pelargonium graveolens L'Her. and Artemisia arborescens L. essential oils: Chemical composition, antifungal activity against Rhizoctonia solani and insecticidal activity against Rhysopertha dominica
Hafsia Bouzenna; Lamia Krichen
The chemical composition of the Pelargonium graveolens essential oil allowed the identification of 15 compounds (93.86% of the total essential oil). The major fractions were citronellol (35%) and geraniol (28.8%). The chemical composition of the Artemisia arborescens essential oil revealed twenty-one compounds representing 93.57% of the total essential oil. The main compounds were chamazulene (31.9%) and camphor (25.8%). The insecticidal
South Carolina Pest Management Handbook for Field Crops -2013 COTTON DISEASE CONTROL
Stuart, Steven J.
every year. Rhizoctonia solani is the most common pathogen with Pythium spp. occurring primarily Rhizoctonia solani and Pythium spp. are capable of infecting most commonly grown rotation crops such as corn
Partnership Sugar Beet Growers
include nematodes, wind damage, Rhizoctonia Crown Rot, Aphanomyces and late season Cercospora leaf spot. Quadris can help control Rhizoctonia Crown Rot. Nitrogen is not the limiting factor for high yield
MSU Extension Publication Archive Archive copy of publication, do not use for current recommendations. Up-to-date
Alternaria collarrot SEVERAL FUNGI--especially Rhizoctonia soiani and Pythium spp.--cause damping off to distinguish between Pythium and Rhizoctonia damping off. Excess moisture and poor aeration are the greatest
South Carolina Pest Management Handbook for Field Crops -2013 PEANUT DISEASE CONTROL
Stuart, Steven J.
diseases such as Cylindrocladium, Aspergillus crown rot, Pythium, and Rhizoctonia. Vitavax PC (Captan. This is true for soil diseases such as white mold and Rhizoctonia limbrot, as well as leaf spot on the foliage
REGULAR ARTICLE Transcriptional profiling in cotton associated with Bacillus
Paré, Paul W.
), in addition to inducing foliar and root growth, disease resistance against damping-off caused by Rhizoctonia, USA #12;pathogen such as Rhizoctonia solani that is able to overwinter as dormant sclerotia
Page 1 Vol. 18 No. 1 A Rutgers Cooperative Extension Publication
Goodman, Robert M.
-off). Com- mon pathogens that cause damping-off include Pythium, Phytophthora, Rhizoctonia and Fusarium spp soils. While rhizoctonia and fusarium are more likely to cause damping-off under warmer, drier
This article was originally published in the Encyclopedia of Virology, Volumes 15 published by Elsevier, and the attached copy is provided by Elsevier for
Baker, Timothy S.
of the genome of a partitivirus from the basidiomycete Rhizoctonia solani. Journal of General Virology 81: 549555. Tavantzis SM and Bandy BP (1988) Properties of a mycovirus from Rhizoctonia solani and its virion
Page 1 Vol. 18 No. 6 A Rutgers Cooperative Extension Publication
Goodman, Robert M.
SL or Quadris (azoxystrobin, 11) at 0.40 to 0.80 fl oz 2.08SC/1000 row ft (for Rhizoctonia only precautions to help control Bottom rot (Rhizoctonia) and Lettuce drop (Sclerotinia) which may cause potential
McDonald, Bruce
AccessResearch article Phylogeography of the Solanaceae-infecting Basidiomycota fungus Rhizoctonia solani Rhizoctonia solani anastomosis group 3 (AG-3) is an important pathogen of cultivated plants in the family
South Carolina Pest Management Handbook for Field Crops -2014 PEANUT DISEASE CONTROL
Duchowski, Andrew T.
diseases such as Cylindrocladium, Aspergillus crown rot, Pythium, and Rhizoctonia. Vitavax PC (Captan such as white mold and Rhizoctonia limbrot, as well as leaf spot on the foliage. Alternating or tank mixing
Cooperative Extension System y Agricultural Experiment Station CIS 1039 Introduction
O'Laughlin, Jay
, creating a favorable environment for Rhizoctonia root rot, black scurf, pink rot, and leak. Also, excessive a number of crown and root diseases. These diseases include take-all, foot rot (eyespot), and Rhizoctonia
Cortes-Barco AM, Goodwin PH, Hsiang T. in press. Induced systemic resistance against three foliar diseases of Agrostis stolonifera by (2R,3R)-Butanediol or an isoparaffin mixture. Annals of Applied
Hsiang, Tom
, Microdochium nivale, Rhizoctonia solani or Sclerotinia homoeocarpa compared to the water control. In A disease caused by the fungus, Rhizoctonia solani (Nandakumar et al., 2001). In Pennisetum glaucum (pearl
15 Mycorrhizal Specificity and Function in Myco-heterotrophic Plants
Taylor, Lee
-heterotrophs . . . . . . . . 000 15.3.1 Overview of Specificity in the Orchidaceae . . . . . . . . . . 000 184.108.40.206 Rhizoctonia orchids associate with wide phylogenetic arrays of Rhizoctonia species, and hence show little specificity
South Carolina Pest Management Handbook for Field Crops -2014 COTTON DISEASE CONTROL
Duchowski, Andrew T.
Carolina every year. Rhizoctonia solani is the most common pathogen with Pythium spp. occurring primarily Rhizoctonia solani and Pythium spp. are capable of infecting most commonly grown rotation crops such as corn
REGULAR ARTICLE Transcriptional profiling in cotton associated with Bacillus
Paré, Paul W.
foliar and root growth, disease resistance against damping-off caused by Rhizoctonia solani was observed such as Rhizoctonia solani that is able to overwinter as dormant sclerotia, clamidospores or in a saprofic form
Sample Category Small Fruit Date Submitted Sample # Host Diagnosis/ID Genus Species Sample County
Jawitz, James W.
/16/2012 5442 Strawberry Water Damage Abiotic disorder Hillsborough 1/17/2012 5444 Strawberry Rhizoctonia Root Rot Thanatephorus Rhizoctonia cucumeris solani Hillsborough 1/18/2012 5445 Strawberry No Pathogen
This article is from the December 2008 issue of
McDonald, Bruce
- and Soybean-Infecting Populations of Rhizoctonia solani Anastomosis Group-1 IA Joana Bernardes de Assis sympatric rice- and soybean-infecting populations of Rhizoctonia solani anastomosis group-1 IA. Phytopathology 98:1326-1333. Rhizoctonia solani anastomosis group (AG)-1 IA causes soybean foliar blighting
Action in vitro d'un herbicide (molinate) sur trois champignons parasites du riz : Sclerotium oryzae Catt.,
Paris-Sud XI, Université de
oryzae Catt., S. hydrophilum Sacc. et Rhizoctonia oryzae Ryker et Gooch Paul BERNAUX Germaine BERTI I, Rhizoctonia oryzae). A des concentrations inférieures ŕ Molinate, ' 0,5 g/1 de matičre active, il provoque un męmes concentrations ou ŕ des concentrations supérieures, la reprise d'activité Rhizoctonia, des
BIOMETRICS58, 129-136 On Estimation and Prediction for Spatial
Zhang, Hao
at unsampled sites. We consider a motivating example that consists of spatial non-Gaussian data of Rhizoctonia of the major limiting factors to direct-seeded wheat and barley is the root disease Rhizoctonia root rot caused by the fungi Rhi- zoctonza solani and Rhizoctonia oryzae (Cook and Haglund, 1991; Cook, 1992). These fungi
Distinctively variable sequence-based nuclear DNA markers for multilocus phylogeography of the soybean-and rice-infecting fungal pathogen
McDonald, Bruce
of the soybean- and rice-infecting fungal pathogen Rhizoctonia solani AG-1 IA Maisa B. Ciampi1 , Liane Rosewich to infer the phylogeographical history of the Basidiomycetous fungal pathogen Rhizoctonia solani AG-1 IA of migration and to reveal cryptic recombina- tion in Rhizoctonia solani (Rosewich et al., 1999; Ceresini et al
of Rhizoctonia. Populations were very high with some varieties above optimum levels. Average harvest population Rhizoctonia Eminent Supertin - Headline Partnership of: Sugar Beet Growers Michigan Sugar Company Michigan amount of Rhizoctonia found in field. Leafspot control was good. Trial looked good all year
MSU Extension Publication Archive Archive copy of publication, do not use for current recommendations. Up-to-date
Smut and leaf spot 3. Rust 4. Sclerotinia dollar spot 6. Fusarium blight 5. Rhizoctonia brown patch of nitrogren and potassium fertilization. 5. Rhizoctonia Brown Patch, Yellow Patch, and Seedling Blight is caused by several species of the fungus Rhizoctonia. Roughly circular, light brown patches of thinned
Funding: Agrochemical Industry Seed Treatment Trials 2008-2009.
Douches, David S.
and seed plus foliar treatments for control of seed- and soil-borne Rhizoctonia, 2008. Potatoes with Rhizoctonia solani (black scurf), 2- 5% tuber surface area infected, were selected for the trials. Potato seed = 21 50%, 5 = 50 100% of the surface of roots, stolons and stem affected by Rhizoctonia. Samples
862 PHYTOPATHOLOGY Population Biology
McDonald, Bruce
862 PHYTOPATHOLOGY Population Biology The Population Genetic Structure of Rhizoctonia solani AG-3PT., and García-Domínguez, C. 2013. The population genetic structure of Rhizoctonia solani AG-3PT from potato in the Colombian Andes. Phytopathology 103:862-869. The soilborne fungus Rhizoctonia solani anastomosis group 3 (AG
1090 PHYTOPATHOLOGY Population Biology
McDonald, Bruce
-Infecting Pathogen Rhizoctonia solani AG-1 IA from China Joana Bernardes-de-Assis, Michelangelo Storari, Marcello, P. C. 2009. Genetic structure of populations of the rice-infecting pathogen Rhizoctonia solani AG-1 by Rhizoctonia solani AG- 1 IA, is one of the most devastating rice diseases on a global basis, including China
Occurrence and distribution of cowpea damping-off and stem rot and associated fungi in Benin
fungi included Sclerotium rolfsii, Fusarium spp., Pythium ultimum, Rhizoctonia solani, Phoma sp & Adandonon 2000) and Rhizoctonia solani Kuehn (Adandonon 2000). The diseases have also been reported., Rhizoctonia solani Kuehn., Phytophthora sp., Fusarium solani (Mart.) App. and Wol. and Sclerotium rolfsii Sacc
Cyclamen mites often cause distorted growth of young developing tissue as shown here on a New Guinea impatiens.
Goodman, Robert M.
), Monolinia blossom blight, crown and basal rots (Rhizoctonia, Pythium, Phytophthora, Fusarium), leaf spots and Phytophthora aerial blight, Rhizoctonia blight, Botrytis rot of tulip, Sclerotinia rot, downy mildews, and Rhizoctonia, and dip treatments to manage Fusarium and Penicillium bulb rot and mold. Do not apply to or allow
This article is from the August 2008 issue of
McDonald, Bruce
of Rhizoctonia solani Anastomosis Group-1 IA from Soybean in Brazil M. B. Ciampi, M. C. Meyer, M. J. N. Costa, M:932-941. The Basidiomycete fungus Rhizoctonia solani anastomosis group (AG)-1 IA is a major pathogen of soybean in Brazil (ana- morph = Rhizoctonia solani) anastomosis group (AG)-1 IA is considered a major pathogen affecting
Le complexe parasitaire du pied du haricot. I. Mise en vidence des principaux champignons
Paris-Sud XI, Université de
.slic, pouvoir pathogčne, Fusarium oxysporum, Rhizoctonia solani, Pythium. SUMMARY Studies on the bean root rot.sarium o-By.!pofu/tt, Fu.sarium solani f. sp. phaseoli, Thielaviopsis ba.sicola, Rhizoctonia solani, Rhizoctonia solani, Pythium. 1. INTRODUCTION La maladie du pied du haricot, dont les symptômes visibles ŕ l
Recherches sur l'cologie des champignons parasites dans le sol
Paris-Sud XI, Université de
infectieux de sols et substrats infestés par Rhizoctonia solani Kühn, agent de fontes de semis Pierre contaminés par Rhizoctonia solani est R. solani, décritc. La terre ŕ analyser, préalablement séchée, broyée infested with Rhizoctonia solani, the Soil infectivity. causal agent of damping-off A technique has been
South Carolina Pest Management Handbook for Field Crops -2014 SOYBEAN DISEASE CONTROL
Duchowski, Andrew T.
.46% + Fludioxonil 2.31% Fusarium spp. Rhizoctonia solani Pythium spp. Phytophthora spp. 1.5 fl. oz. per cwt. ApronMaxx RTA Mefenoxam 1.01% + Fludioxonil 0.73% Fusarium spp. Rhizoctonia solani Pythium spp. Phytophthora spp.67% Fusarium spp. Pythium spp. Phytophthora spp. Rhizoctonia solani 5.0 fl. oz. per cwt. Bean Guard
International Turfgrass Society Research Journal Volume 9, 2001.
Hsiang, Tom
complex known as Rhizoctonia solani Kuehn has been divided into at least 12 anastomosis groups (AG and Martin [1992] in their review of Rhizoctonia species associated with turfgrasses, list AG1, AG2-2, email@example.com. DNA SEQUENCING FOR ANASTOMOSIS GROUPING OF RHIZOCTONIA SOLANI ISOLATES FROM POA ANNUA T. Hsiang* and J
Turfgrass Disease Profiles Purdue extension
to as cool sea- son brown patch, is caused by Rhizoctonia cerealis, a fungus closely related to the pathogens that cause brown patch and the Rhizoctonia large patch of zoysia grass (for more on these diseases, see.pdf, and Rhizoctonia Large Patch, http://www. ces.purdue.edu/extmedia/BP/BP-117-W.pdf). Although symptoms can
USDA-ARS Tree Fruit Research Laboratory, Wenatchee, United States of America PROGRESS TOWARDS DEVELOPMENT
Cohen, Michael F.
fumigation. RSM-induced control of Rhizoctonia solani resulted from the enhanced activity of resident soil resistance, brassicaceae seed meal, microbial ecology, Rhizoctonia solani, Pratylenchus, Pythium Introduction., Pythium spp., and Rhizoctonia solani. WVC, but not CV, orchard soils also possessed significant lesion
Abstract Amendment of orchard soil with low-glucosinolate Brassica napus (rape) seed meal
Cohen, Michael F.
) suppresses infection of apple roots by Rhizoctonia solani but increases incidence of Pythium spp. infection Nitrification Ć Pythium Ć Rhizoctonia root rot Ć Streptomyces Introduction Replant disease of apple is caused by complexes of root-pathogens, often including the fungus Rhizoctonia solani (Mazzola 1998), that become
Brassica napus seed meal soil amendment modifies microbial community structure, nitric oxide production and incidence
Cohen, Michael F.
production and incidence of Rhizoctonia root rot M.F. Cohena , H. Yamasakib , M. Mazzolaa,* a USDA-ARS, 1104 micro-organisms. RSM amendment reduced infection by native and introduced isolates of Rhizoctonia spp. and recovery of Pratylenchus spp. from apple roots. Root infection by Rhizoctonia solani AG-5 was also
Turfgrass Disease Profiles PURDUE EXTENSION
Turfgrass Disease Profiles PURDUE EXTENSION Figure 1 Figure 2 Figure 3 BP-117-W Rhizoctonia large of the zoysiagrass (Zoysia japonica) species. RLP is caused by a strain of Rhizoctonia solani that causes damage of radial growth from an initial infection Rhizoctonia Large Patch Aaron Patton, Graduate Research Assistant
Pathologie vgtale Influence des successions culturales
Paris-Sud XI, Université de
(Rhizoctonia cerealis) ont été notés ŕ la floraison sur tige et racines. Les résultats obtenus ont permis de / Gaeumannomyces graminis / Rhizoctonia cerealis / suc- cession culturale / capacité d'hôtes des cultures / modčles eyespot (Rhizoctonia cerealis). As a conse- quence, we can propose a simple model of the effect
Pressure Cycling Technology Sample Preparation System (PCT SPS) Improves Quantification of Pathogen DNA in Plants and Soil
Technology Transfer Automated Retrieval System (TEKTRAN)
Rhizoctonia root rot, bare patch, and damping-off of wheat are yield-limiting diseases caused by Rhizoctonia solani AG-8 and R. oryzae. Detection and quantification of Rhizoctonia spp. are essential for evaluating pathogen distribution and management, but extraction of DNA from these pathogens is ha...
South Carolina Pest Management Handbook for Field Crops -2013 SOYBEAN DISEASE CONTROL
Stuart, Steven J.
. oz. per cwt. ApronMaxx RFC Mefenoxam 3.46% + Fludioxonil 2.31% Fusarium spp. Rhizoctonia solani.73% Fusarium spp. Rhizoctonia solani Pythium spp. Phytophthora spp. 5.0 fl. oz. per cwt. ApronMaxx RTA + Moly. Rhizoctonia solani 5.0 fl. oz. per cwt. Bean Guard/Allegiance Carboxin 12.5% Metalaxyl 3.75% Captan 24.45% 11
Cloning of a chitinase-like cDNA ( hs2), its transfer to creeping bentgrass ( Agrostis palustris Huds.) and development of brown patch ( Rhizoctonia solani) disease resistant transgenic lines
Benli Chai; Shahina B Maqbool; Ravindra K Hajela; David Green; Joseph M Vargas; Donald Warkentin; Robab Sabzikar; Mariam B Sticklen
We isolated a cDNA clone (hs2) encoding a chitinase-like protein from a triploid Dutch elm disease resistant American elm (Ulmus americana NPS-3-487). Amino acid sequence of this chitinase-like protein showed 65–78% homology to other plant chitinases. A plasmid KYLX71-pHS2 was constructed using the hs2 sequence under the control of cauliflower mosaic virus 35S promoter and nos terminator. This construct was
Over-expression of the cloned rice thaumatin-like protein (PR5) gene in transgenic rice plants enhances environmental friendly resistance to Rhizoctonia solani causing sheath blight disease
K. Datta; R. Velazhahan; N. Oliva; I. Ona; T. Mew; G. S. Khush; S. Muthukrishnan; S. K. Datta
A 1.1-kb DNA fragment containing the coding region of a thaumatin-like protein (TLP-D34), a member of the PR-5 group, was\\u000a cloned into the rice transformation vector pGL2, under the control of the CaMV 35S promoter. The Indica rice cultivars, 'Chinsurah\\u000a Boro II', 'IR72', and 'IR51500' were transformed with the tlp gene construct by PEG-mediated direct gene transfer to protoplasts and
Response of azalea cuttings to leaf damage and leaf removal
Technology Transfer Automated Retrieval System (TEKTRAN)
Binucleate Rhizoctonia species, the pathogens that cause azalea web blight, can be carried on stem cuttings, perpetuating the disease through subsequent crops. Previous studies have demonstrated that submerging Rhizoctonia-infested stem pieces of 'Gumpo White' azalea in 122°F (50°C) water for 20 min...
Do chlorophyllous orchids heterotrophically use mycorrhizal fungal carbon?
Selosse, Marc-André; Martos, Florent
The roots of orchids associate with mycorrhizal fungi, the rhizoctonias, which are considered to exchange mineral nutrients against plant carbon. The recent discovery that rhizoctonias grow endophytically in non-orchid plants raises the possibility that they provide carbon to orchids, explaining why some orchids differ in isotopic abundances from autotrophic plants. PMID:25278267
From the PDC: Onion leek moth-still getting lots of reports, mainly from home gardeners but be on the lookout. There
Hayden, Nancy J.
Brassicas-Lots of rhizoctonia wirestem samples in the lab. If plants are struggling, look at the root/cool conditions, but plants are showing symptoms now due to stress of no roots. http://www.omafra.gov.on.ca/IPM/english/brassicas/diseases-and-disorders/rhizoctonia
Control effect of lanthanum against plant disease
Yajia LIU; Yan WANG; Fubin WANG; Yuming LIU; Jianyu CUI; Lin HU; Kangguo MU
Effect of La on emergence, growth and development of Isatis indigotica Fort. and Festuca arundinacea seedlings was researched by pot experiments of inoculating Rhizoctonia solani and with the mixture of Rhizoctonia solani and Fusarium solani in disinfected soil after the seeds were soaked in the solution with different concentrations of La3+. The results indicated that infection rate decreased and there
Application of real-time PCR for quantification of soilborne pathogens
Technology Transfer Automated Retrieval System (TEKTRAN)
Soilborne pathogens can be particularly difficult to quantify. Unlike foliar diseases, symptoms caused by soilborne pathogens such as Pythium and Rhizoctonia spp. are not readily observable, making it difficult to estimate pathogen populations. Pythium and Rhizoctonia present an additional problem i...
Fungicide timing rules to prevent azalea web blight damage
Technology Transfer Automated Retrieval System (TEKTRAN)
This article provides directions for timing fungicide applications to control Rhizoctonia web blight. Research has shown that many azalea cultivars are infested with the web blight pathogen (binucleate Rhizoctonia). The fungus lives 12 months of the year on azaleas, yet does not harm the plant most...
Fungicide timing rules to prevent azalea web blight damage
Technology Transfer Automated Retrieval System (TEKTRAN)
This article provides directions for timing fungicide applications to control Rhizoctonia web blight. Research has shown that many azalea cultivars are infested with the web blight pathogen (binucleate Rhizoctonia). The fungus lives 12 months of the year on azaleas, yet does not harm the plant most ...
Pressure Cycling Technology Sample Preparation System (PCT SPS) Improves Quantification of Pathogen DNA in Plants and Soil
Technology Transfer Automated Retrieval System (TEKTRAN)
Wheat and barley are susceptible to Rhizoctonia root rot, bare patch, and damping-off in the dryland cereal production regions of the Pacific Northwest and throughout the world. Detection and quantification of Rhizoctonia spp., the causal agents of this yield-limiting disease, are inconsistent at lo...
Technology Transfer Automated Retrieval System (TEKTRAN)
Application of fungicides such as Quadris, Pristin, Flint Rovral and Switch to the base of young lettuce plants after thinning and one week later reduced the incidence of disease caused by Rhizoctonia solani....
7 CFR 51.3416 - Classification of defects.
Code of Federal Regulations, 2012 CFR
... Grub 5% waste 10% waste. Ingrown sprouts 5% waste 10% waste. Nematodes 5% waste 10% waste. Rhizoctonia, solid or thick mounded Not more than 10% of surface Not more than 25% of surface. Rodent, bird damage 5%...
7 CFR 51.3416 - Classification of defects.
Code of Federal Regulations, 2011 CFR
... Grub 5% waste 10% waste. Ingrown sprouts 5% waste 10% waste. Nematodes 5% waste 10% waste. Rhizoctonia, solid or thick mounded Not more than 10% of surface Not more than 25% of surface. Rodent, bird damage 5%...
7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.
Code of Federal Regulations, 2014 CFR
...growth, growth cracks, air cracks, hollowheart, internal discoloration, cuts, shriveling, sprouting, scab, dry rot, rhizoctonia, other diseases, wireworm, other insects, or mechanical or other means. Potatoes of these grades shall also be...
7 CFR 51.3416 - Classification of defects.
Code of Federal Regulations, 2014 CFR
... Grub 5% waste 10% waste. Ingrown sprouts 5% waste 10% waste. Nematodes 5% waste 10% waste. Rhizoctonia, solid or thick mounded Not more than 10% of surface Not more than 25% of surface. Rodent, bird damage 5%...
78 FR 76611 - Pesticide Experimental Use Permit; Notice of Receipt of Application; Comment Request
Federal Register 2010, 2011, 2012, 2013, 2014
...For use as a seed treatment on corn for efficacy against seedling infections of soilborne plant pathogenic fungi Fusarium, Rhizoctonia, Pythium and Colletotrichum, and to aid in suppression of late season stalk rot. This is a crop-destruct EUP....
7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.
Code of Federal Regulations, 2012 CFR
...growth, growth cracks, air cracks, hollowheart, internal discoloration, cuts, shriveling, sprouting, scab, dry rot, rhizoctonia, other diseases, wireworm, other insects, or mechanical or other means. Potatoes of these grades shall also be...
7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.
Code of Federal Regulations, 2011 CFR
...growth, growth cracks, air cracks, hollowheart, internal discoloration, cuts, shriveling, sprouting, scab, dry rot, rhizoctonia, other diseases, wireworm, other insects, or mechanical or other means. Potatoes of these grades shall also be...
7 CFR 51.3416 - Classification of defects.
Code of Federal Regulations, 2010 CFR
... Grub 5% waste 10% waste. Ingrown sprouts 5% waste 10% waste. Nematodes 5% waste 10% waste. Rhizoctonia, solid or thick mounded Not more than 10% of surface Not more than 25% of surface. Rodent, bird damage 5%...
7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.
Code of Federal Regulations, 2010 CFR
...growth, growth cracks, air cracks, hollowheart, internal discoloration, cuts, shriveling, sprouting, scab, dry rot, rhizoctonia, other diseases, wireworm, other insects, or mechanical or other means. Potatoes of these grades shall also be...
7 CFR 51.3416 - Classification of defects.
Code of Federal Regulations, 2013 CFR
... Grub 5% waste 10% waste. Ingrown sprouts 5% waste 10% waste. Nematodes 5% waste 10% waste. Rhizoctonia, solid or thick mounded Not more than 10% of surface Not more than 25% of surface. Rodent, bird damage 5%...
7 CFR 51.1575 - U.S. Grade A Small; U.S. Grade A Medium; U.S. Grade A Medium to Large; U.S. Grade A Large.
Code of Federal Regulations, 2013 CFR
...growth, growth cracks, air cracks, hollowheart, internal discoloration, cuts, shriveling, sprouting, scab, dry rot, rhizoctonia, other diseases, wireworm, other insects, or mechanical or other means. Potatoes of these grades shall also be...
Soil microbial response to glyphosate-base cotton pest management systems
Lancaster, Sarah Renee
on fluometuron degradation; 3) evaluate the response of Rhizoctonia solani to glyphosate and fluometuron; 4) study changes in glyphosate metabolism that occur as a result of repeated glyphosate applications; and 5) define shifts in the soil microbial community...
Synthetic peptide combinatorial libraries: an approach to identifying antimicrobials for the control of plant pathogens
Reed, Jerry Douglas
different peptide mixtures was synthesized. The library was tested for biological activity against Fusarium oxysporum f.sp. lycopersici and Rhizoctonia solani (AG-1). Initial screening of the 400 peptide mixture library identified biologically active...
Metal complex of the first-generation quinolone antimicrobial drug nalidixic acid: structure and its biological evaluation.
Debnath, Anamika; Mogha, Navin Kumar; Masram, Dhanraj T
A novel binuclear squire planar complex of nalidixic acid with Ag(I) metal ion with the formula [Ag(Nal)2] has been synthesized. The synthesized metal complex was characterized using CHN analysis, Fourier-transformed infra-red (FT-IR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), ultra violet-visible (Uv-vis) and single-crystal X-ray diffraction (XRD). The newly synthesized complex shows more advanced antifungal activity compared to the parent quinolone against four fungi, namely Pythium aphanidermatum, Sclerotinia rolfsii, Rhizoctonia solani and Rhizoctonia bataticola. PMID:25547815
Multistate evaluation of Brassica cover crop, biocontrol agent, and fungicide for integrated management of sheath blight
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight, caused by Rhizoctonia solani, is one of the most important diseases limiting rice production in the southern rice-producing states. The fungus survives between crops as sclerotia and mycelia in infected plant debris and serves as the primary inoculum. Infection starts when sclerotia a...
Brassica cover cropping for management of sheath blight of rice
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight, caused by Rhizoctonia solani, is the most important disease limiting rice production in Texas and other rice-producing states. The fungal pathogen survives between crops as soilborne sclerotia and mycelium in infected plant debris. These sclerotia and colonized plant debris float on t...
Confirming QTLs and finding additional Loci responsible for resistance to Sheath Blight in Rice
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice sheath blight (ShB) caused by the soil borne pathogen Rhizoctonia solani, is one of the most destructive diseases of rice around the globe, causing severe losses in rice yield and quality annually. Major genes governing resistance to ShB have not been found in cultivated rice worldwide; however...
Rooting response of azalea cultivars to hot water treatment used for pathogen conrol
Technology Transfer Automated Retrieval System (TEKTRAN)
Submerging terminal leafy cuttings of Rhododendron L. 'Gumpo White' ('Gumpo White' azalea) in 50 °C water for 21 min was previously shown to eliminate binucleate Rhizoctonia species, the cause of azalea web blight, from plant tissues. Prior to considering commercial use of this practice, a better un...
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice wild relatives (Oryza spp.) are an important source of novel R(resistance)-genes for rice improvement. Rice sheath blight, caused by Rhizoctonia solani, and leaf blast, caused by Magnaporthe grisea, are major fungal diseases of cultivated rice (O. sativa) in the USA and of irrigated rice world...
Technology Transfer Automated Retrieval System (TEKTRAN)
In the USA, newly introduced rice germplasm is one source of novel resistance genes to blast, Magnaporthe grisea, and sheath blight, Rhizoctonia solani, major fungal diseases of irrigated rice (Oryza sativa). Resistance to U.S. blast races was observed in 91 of approximately 1,000 newly introduced ...
Inhibitory effects of stilbenes on the growth of three soybean pathogens in culture
Technology Transfer Automated Retrieval System (TEKTRAN)
The effects of resveratrol and pterostilbene on in vitro growth of three soybean pathogens were tested to determine if these stilbenic compounds could potentially be targets to increase innate resistance in transgenic soybean plants. Growth of Macrophomina phaseolina, Rhizoctonia solani, and Sclerot...
Use of biocontrol organisms and compost amendments for improved control of soilborne diseases and increased potato production
Technology Transfer Automated Retrieval System (TEKTRAN)
Soilborne potato diseases are persistent problems in potato production and alternative management practices are needed. In this research, biocontrol agents (Bacillus subtilis GB03 and Rhizoctonia solani hypovirulent isolate Rhs1A1) and compost amendments (from different source material), were evalua...
Identification of quantitative trait loci (QTLs) responsible for sheath blight resistance in rice using recombinant inbred line population of Lemont X Jasmine 85
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice sheath blight (RSB) caused by the soil borne pathogen Rhizoctonia solani, is one of the most destructive diseases of rice, causing severe losses in rice yield and quality annually. The major gene (s) governing the resistance to RSB have not been found in cultivated rice worldwide. However, ri...
Identification of Sheath Blight Resistance QTLs in Rice Using Recombinant Inbred Line Population of Lemont X Jasmine 85
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice sheath blight (RSB) caused by the soil borne pathogen Rhizoctonia solani, is one of the most destructive diseases of rice around the globe, causing severe losses in rice yield and quality annually. Major gene(s) governing the resistance to RSB have not been found in cultivated rice worldwide...
Analysis of rice PDR-like ABC transporter genes in sheath blight resistance
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight caused by Rhizoctonia solani is one of the most damaging diseases of rice worldwide. To understand the molecular mechanism of resistance, we identified 450 differentially expressed genes in a resistant rice cultivar Jasmine 85 after R. solani infection with a combination of DNA microar...
Sintomatología y Géneros de Patógenos Asociados con las Pudriciones de la Raíz del Chile (Capsicum annuum L.) en el Norte-Centro de México
Rodolfo Velásquez-Valle; María Mercedes Medina-Aguilar; Jesús María
Root rots are the main phytopathological problem of pepper crop in North-Central Mexico. In field surveys carried out during the year 2000 in the States of Aguascalientes and Zacatecas, the fungi Rhizoctonia spp., Fusarium spp., Phytophthora spp., Verticillium spp, and Pythium spp. were detected in roots of diseased plants. The symptomatology associated to pepper root rots included defoliation, color change
Cultivar selection for bacterial root rot in sugar beet
Technology Transfer Automated Retrieval System (TEKTRAN)
Bacterial root rot of sugar beet caused by Leuconostoc mesenteroides subsp. dextranicum is a disease problem recently described in the United States, which has frequently been found in association with Rhizoctonia root rot. To reduce the impact of bacterial root rot on sucrose loss in the field, st...
Root rot in sugar beet piles at harvest
Technology Transfer Automated Retrieval System (TEKTRAN)
Sugar beet root rots are not only a concern because of reduced yields, but can also be associated with losses in storage. Our primary sugar beet root rot disease problem in the Amalgamated production area is Rhizoctonia root rot. However, this rot frequently only penetrates a short distance past t...
Introduction Proper irrigation timing can maximize sugar-
O'Laughlin, Jay
Introduction Proper irrigation timing can maximize sugar- beet yields while minimizing disease- cially with furrow irrigation. Root diseases such as rhizomania and rhizoctonia root and crown rots will be reduced. Unnecessary irrigations can be reduced if grow- ers use information on water status at deeper
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight (SB), caused by the fungus Rhizoctonia solani Kühn, is a destructive disease of rice (Oryza sativa L.) causing severe loss in grain yield and quality each year in the U.S. and elsewhere. Resistance has been reported to be horizontal and quantitative, and does not follow the gene-for-ge...
Differential sensitivity of rice pathogens to growth inhibition by flavonoids
Manchikanti Padmavati; Natarajan Sakthivel; K. V. Thara; Arjula R. Reddy
Differential sensitivity of the major pathogens of rice, Xanthomonas oryzae pv. oryzae, Pyricularia oryzae and Rhizoctonia solani to inhibition by certain flavonoids was tested using paper disc\\/liquid culture and spore germination assays. Naringenin, the first intermediate of the flavonoid pathway, displayed growth inhibition of Xanthomonas strains and spore germination of P. oryzae. On the other hand, no such inhibition was
Molecular dynamics of interactions of rice with rice blast and sheath blight pathogens
Technology Transfer Automated Retrieval System (TEKTRAN)
In an effort to develop the molecular strategies to control rice (Oryzae sativa) diseases, molecular interactions of rice with rice blast [Magnaporthe oryzae, formerly (Magnaporthe grisea] and sheath blight (Rhizoctonia solani) fungi were analyzed. The interaction of rice with M. oryzae follows a b...
Technology Transfer Automated Retrieval System (TEKTRAN)
Necrotrophic root pathogens cause chronic yield losses in cereal-growing regions of the Pacific Northwest and throughout the world. We have developed real-time PCR assays for pathogenic Pythium and Rhizoctonia spp. isolated from symptomatic sites throughout the dryland cereal production regions of t...
Characterization of a novel plant growth-promoting bacteria strain Delftia tsuruhatensis HR4 both as a diazotroph and a potential biocontrol agent against various plant pathogens
Jigang Han; Lei Sun; Xiuzhu Dong; Zhengqiu Cai; Xiaolu Sun; Hailian Yang; Yunshan Wang; Wei Song
A novel, plant growth-promoting bacterium Delftia tsuruhatensis, strain HR4, was isolated from the rhizoplane of rice (Oryza sativa L., cv. Yueguang) in North China. In vitro antagonistic assay showed this strain could suppress the growth of various plant pathogens effectively, especially the three main rice pathogens (Xanthomonas oryzae pv. oryzae, Rhizoctonia solani and Pyricularia oryzae Cavara). Treated with strain HR4
Seedling disease resistance screening assays
Technology Transfer Automated Retrieval System (TEKTRAN)
A number of pathogens can cause early season stand loss in sugar beet. Fungi such as Rhizoctonia solani AG-2-2 and AG-4 and Fusarium oxysporum are able to cause post-emergence damping-off in sugar beet. Recent work has identified some sugar beet germplasms which show reduced damage from isolates of ...
Sterol-inhibiting fungicide impacts on soil microbial ecology in Atlantic Coastal Plain soils
P. M. White; T. L. Potter; T. C. Strickland
Seventy-five percent of the peanuts (Arachus hypogaia) produced in the United States are grown in the Atlantic Coastal Plain region. Portions of this area, including Alabama and Georgia, exhibit a subtropical climate that promotes soil-borne plant fungal diseases. Most fields receive repeated fungicide applications during the growing season to suppress the disease causing organisms, such as Sclerotium rolfsii, Rhizoctonia solani,
Biological Control of Fusarium Wilt on Cotton by Use of Endophytic Bacteria
C. Chen; E. M. Bauske; G. Musson; R. Rodriguezkabana; J. W. Kloepper
One hundred seventy bacterial strains isolated from internal tissues of cotton, 49 strains with known biological control activity against Rhizoctonia solani in cotton, and 25 strains known to induce systemic resistance to Collectotrichum orbiculare in cucumber, were screened for biological control potential against vascular wilt of cotton caused by Fusarium oxysporum f. sp. vasinfectum. The strains were introduced as endophytes
Rapeseed rotation, compost and biocontrol amendments reduce soilborne diseases and increase tuber yield in conventional and organic potato production systems
Technology Transfer Automated Retrieval System (TEKTRAN)
Three different potential disease-suppressive management practices, including a Brassica napus (rapeseed) green manure rotation crop, a conifer-based compost amendment, and three biological control organisms (Trichoderma virens, Bacillus subtilis, and Rhizoctonia solani hypovirulent isolate Rhs1A1)...
Promises and challenges of genomics for rice pathology
Technology Transfer Automated Retrieval System (TEKTRAN)
Publically available genome sequences of Magnaporthe oryzae, Rhizoctonia solani, and Oryza sativa are being used to study host-pathogen interactions. Comparative genomic analyses on natural alleles of major resistance (R) genes and the corresponding avirulence (AVR) genes have provided new clues for...
Genetic and genomic dissection of resistance genes to the rice sheath blight pathogen
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice sheath blight disease caused by the anastomosis group AG1-IA of the fungal pathogen Rhizoctonia solani is one of the most serious rice diseases in the southern US and the world. The use of fungicides is a popular but costly method to control this disease worldwide. Genetic analysis of host re...
Microbial degradation of fluometuron is influenced by Roundup WeatherMAX
Technology Transfer Automated Retrieval System (TEKTRAN)
Laboratory experiments were conducted to describe the influence of glyphosate and fluometuron on soil microbial activity and to determine the effect of glyphosate on fluometuron degradation in soil and by Rhizoctonia solani. Soil and liquid medium were amended with formulated fluometuron alone or w...
Fungi threatening the cultivation of sage (Salvia officinalis L.) in south-eastern Poland
S u m m a r y In 2004-2006 there were studies conducted on fungi colonizing and harming different parts of plants on plantations of sage (Salvia officinalis L.) grouped in south-eastern Poland. Fungi were isolated from roots, the stem base and leaves. The surface was disinfected by means of a mineral medium. Fungi from genera Fusarium, Rhizoctonia solani, Phoma
Code of Federal Regulations, 2010 CFR
...more than 5 percent of the total weight of the potato including peel covering defective area. Loss of outer skin (epidermis...more than 5 percent of the total weight of the potato including peel covering defective area. (g) Rhizoctonia, when the...
Code of Federal Regulations, 2014 CFR
...or causes a loss of more than 5 percent of the total weight of the potato including peel covering defective area. (g) Rhizoctonia, when the general appearance of the potatoes in the container is materially injured or when individual potatoes are...
7 CFR 51.1564 - External defects.
Code of Federal Regulations, 2012 CFR
...than 5 percent of total weight of potato When removal causes loss of more than 10 percent of total weight of potato. Rhizoctonia When affecting more than 15 percent of the surface in the aggregate When affecting more than 50 percent of the...
7 CFR 51.1564 - External defects.
Code of Federal Regulations, 2014 CFR
...than 5 percent of total weight of potato When removal causes loss of more than 10 percent of total weight of potato. Rhizoctonia When affecting more than 15 percent of the surface in the aggregate When affecting more than 50 percent of the...
Code of Federal Regulations, 2012 CFR
...or causes a loss of more than 5 percent of the total weight of the potato including peel covering defective area. (g) Rhizoctonia, when the general appearance of the potatoes in the container is materially injured or when individual potatoes are...
Code of Federal Regulations, 2013 CFR
...or causes a loss of more than 5 percent of the total weight of the potato including peel covering defective area. (g) Rhizoctonia, when the general appearance of the potatoes in the container is materially injured or when individual potatoes are...
7 CFR 51.1564 - External defects.
Code of Federal Regulations, 2010 CFR
...than 5 percent of total weight of potato When removal causes loss of more than 10 percent of total weight of potato. Rhizoctonia When affecting more than 15 percent of the surface in the aggregate When affecting more than 50 percent of the...
Code of Federal Regulations, 2011 CFR
...or causes a loss of more than 5 percent of the total weight of the potato including peel covering defective area. (g) Rhizoctonia, when the general appearance of the potatoes in the container is materially injured or when individual potatoes are...
The multiple personalities of Streptomyces spp. from the rhizosphere of apple cultivated in brassica seed meal ameded soils
Technology Transfer Automated Retrieval System (TEKTRAN)
Brassicaceae seed meal soil amendments proved control of Rhizoctonia root rot, in part, through the proliferation of indigenous rhizosphere colonizing Streptomyces spp. Studies were conducted to assess the relative role of antibiosis and nitric oxide (NO) production in the capacity of Streptomyces ...
Antagonistic effect of Pseudomonas spp. on pathogenic fungi and enhancement of growth of green gram (Vigna radiata)
S. S. Sindhu; S. K. Gupta; K. R. Dadarwal
Pseudomonas species were isolated from the rhizosphere of green gram [Vigna radiata (L.) Wilczek] and some of the rhizobacterial isolates were found to have a wide range of antifungal activity inhibiting growth\\u000a of the phytopathogenic fungi Aspergillus sp., Curvularia sp., Fusarium oxysporum and Rhizoctonia solani in culture. These isolates also showed slight inhibition of the growth of a Bradyrhizobium strain
Stimulation of nodulation and plant growth of chickpea ( Cicer arietinum L . ) by Pseudomonas spp. antagonistic to fungal pathogens
A. K. Goel; S. S. Sindhu; K. R. Dadarwal
Two strains of Pseudomonas MRS23 and CRP55b showed antagonistic activity towards the pathogenic fungi Aspergillus sp., Fusarium oxysporum f. sp. ciceri, Pythium aphanidermatum and Rhizoctonia solani under culture conditions. Larger growth inhibition zones were obtained on nutrient agar (NA) and King's B media in comparison to potato dextrose agar and pigment production media. Both the strains produced siderophore in agar
Observed Differences in Life History Characteristics of Nematodes Aphelenchus and Acrobeloides upon Exposure to Copper and Benzo(a)pyrene
Neher, Deborah A.
Exposure to Copper and Benzo(a)pyrene FAFENG LI1 , DEBORAH A. NEHER2, *, BRIAN J. DARBY2 AND THOMAS R of Escherichia coli and Rhizoctonia solani, respectively. LC50 values for Aphelenchus exposed to copper or benzo(a)pyrene (BaP) are greater than Acrobeloides. Copper impedes growth of Acrobeloides at 10 lg/g, and results
Current progress on genetic interactions of rice with rice blast and sheath blight fungi
Technology Transfer Automated Retrieval System (TEKTRAN)
Analysis of genetic interactions between rice and its pathogenic fungi Magnaporthe oryzae and Rhizoctonia solani should lead to a better understanding of molecular mechanisms of host resistance, and the improvement of strategies to manage rice blast and sheath blight diseases. Presently dozens of ri...
Sheath-blight resistance QTLs and in japonica rice germplasm
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight (SB), caused by Rhizoctonia solani, is one of the most serious diseases of cultivated rice (Oryza sativa L.) and genetic resistance is in demand by rice breeders. With the goal of resistance-QTL discovery in U. S. japonica breeding material, a set of 197 F1 doubled-haploid lines (DHLs)...
Non-Fumigant management of apple replant disease in organic and conventional systems
Technology Transfer Automated Retrieval System (TEKTRAN)
Brassica tissues are often promoted as a soil amendment for control of soilborne plant diseases due to their production of glucosinolates, which yield anti-microbial compounds upon hydrolysis. Studies demonstrated that mechanisms operating in the control of Rhizoctonia root rot of apple in response ...
Efficacy of brassicaceous seed meal formulations for the control of apple replant disease in conventional and organic production systems
Technology Transfer Automated Retrieval System (TEKTRAN)
Brassica tissues are often promoted as a soil amendment for control of soilborne plant diseases due to their production of glucosinolates, which yield anti-microbial compounds upon hydrolysis. Studies demonstrated that mechanisms operating in the control of Rhizoctonia root rot of apple in response ...
Effect of single application of Trichoderma viride and Pseudomonas fluorescens on growth promotion in cotton plants
V. Shanmugaiah; N. Balasubramanian; S. Gomathinayagam; P. T. Manoharan
The most important and economically cultivated cotton plant was selected to test the growth promotion by Trichoderma viride and Pseudomonas fluroescens with and without pathogens, Rhizoctonia solani and Macrophomina phaseolina. Of these, T. viride was found to be more effective than P. fluroescens on shoot and root length elongation. Seed germination percentage, root length, shoot length, fresh weight, dry weight
Mycoflora and Potential for Mycotoxin Production of Freshly Harvested Black Bean from the Argentinean Main Production Area
M. D. Castillo; H. H. L. González; E. J. Martínez; A. M. Pacin; S. L. Resnik
A mycological survey was carried out, for the first time, on black bean samples from the northwestern Argentinean province of Salta in the 1999 harvest season. Ten varieties of black beans were evaluated at three locations. Species of the genus Alternaria were the most prevalent component of the black bean mycoflora. Species of Fusarium, Sclerotinia, Rhizoctonia and Acremonium were also
Technology Transfer Automated Retrieval System (TEKTRAN)
The fungus causing violet root rot, Helicobasidium brebissonii (anamorph Rhizoctonia crocorum), is widely distributed in Europe and North America but is rarely of much economic importance on alfalfa. The disease has also been reported in Australia, Argentina, and Iran. The disease is characterized b...
Synthesis and biological activities of fluorine-containing N, N?-diphenylcarbamimidothioates
Zhibin Li; Xuhong Qian; Gonghua Song; Zhong Li
A series of fluorine-containing N,N?-diphenylcarbamimidothioates 6a-i have been synthesized by treatment of the corresponding arylamine with the aryl isothiocyanate in ethanol at room temperature followed by treatment with methyl iodide. The antifungal activities against the fungi Rhizoctonia solani and Pyricoraria orizae of the title compounds have been screened.
Syntheses and activities as trehalase inhibitors of N-arylglycosylamines derived from fluorinated anilines
Xuhong Qian; Zhibin Li; Zhi Liu; Gonghua Song; Zhong Li
Twelve N-arylglycosylamines were prepared in a one-pot reaction by treatment of d-glucose, d-galactose, d-mannose or d-xylose with fluorinated anilines in the presence of small amount of hydrochloric acid. The inhibitory activity against porcine trehalase and the fungicidal activity of the title compounds toward Rhizoctonia solani have been tested.
Development and characterization of RiceCAP QTL mapping population for sheath blight resistance
Technology Transfer Automated Retrieval System (TEKTRAN)
RiceCAP is a USDA CSREES funded project that has as one of its main objectives developing genetic markers associated with sheath blight resistance. Sheath blight, caused by Rhizoctonia solani, is an important disease of rice in the southern US. Tolerance to the disease is quantitatively inherited an...
Technology Transfer Automated Retrieval System (TEKTRAN)
Single-plant selections in compacted and infested (Rhizoctonia solani and Fusarium solani) field plots were made among and within populations of common bean (Phaseolus vulgaris L.) based on general plant vigor. The following year, geometric means for seed yield of compacted/infested field plots and...
The mission of Sugarbeet Advancement is to generate research and utilize
of the industry has been realized and producers have adopted the latest technology. Make no mistake; productive, Agriculturalists and Seed Company Representatives. Special thanks again this year goes to Doug Ruppal of Hilleshog Seeds for planting and managing the Amistar/Rhizoctonia trials. Other contributors include: Andy Bernia
Beauveria bassiana: Endophytic colonization and plant disease control
Bonnie H. Ownley; Mary R. Griffin; William E. Klingeman; Kimberly D. Gwinn; J. Kevin Moulton; Roberto M. Pereira
Seed application of Beauveria bassiana 11-98 resulted in endophytic colonization of tomato and cotton seedlings and protection against plant pathogenic Rhizoctonia solani and Pythium myriotylum. Both pathogens cause damping off of seedlings and root rot of older plants. The degree of disease control achieved depended upon the population density of B. bassiana conidia on seed. Using standard plating techniques onto
Searching for Germplasm Resistant to Sheath Blight from the USDA Rice Core Collection
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight, caused by the fungal pathogen Rhizoctonia solani, is one of the most important and widely distributed diseases capable of infesting numerous crops including rice. Resistant germplasm with wide variation is essential for controlling this disease via breeding efforts, and genetic backgr...
Peanut peg strength and anatomy as related to disease resistance
Thomas, Ronald James
extensive fungal ramifi- cation. Peg inoculated with Rhizoctonia----------- 86 22 Close-section of P. I. 393647 showing collapsed nec- rotic tissue. No fungal hyphae evident. Peg dd d' 1 d 'M~Mh ' ? ? ? ? ? -90 23 Cross-sections of P. I. 393647 showing...
Antifungal activity of lichen extracts and lichenic acids
Patrice Halama; Chantal Van Haluwin
Acetone extracts of the threelichen species Evernia prunastri, Hypogymnia physodes and Cladoniaportentosa were investigated for activityagainst eight plant pathogenic fungi: Pythium ultimum, Phytophthorainfestans, Rhizoctonia solani, Botrytis cinerea, Colletotrichumlindemuthianum, Fusarium solani, Stagonospora nodorum and Ustilagomaydis. Particularly, E. prunastriand H. physodes exhibit total or stronginhibition on P. ultimum, U.maydis and P. infestans growth. Incontrast, Cladonia extracts were lessactive to reduce growth of
The presence of root-knot nematode, Meloidogyne incognita was assessed on roots and rhizosphere soil of cock's comb (Celosia argentea L.) planted in 5 lawns located at the campus of University of Agriculture, Faisalabad. The infected plants were stunted with galled and rotted roots. Four fungal pathogens including Fusarium, Pythium, Rhizoctonia and Sclerotia were isolated from nematode-fungal complex infected roots. Plant
Fungicidal activity of pipernonaline, a piperidine alkaloid derived from long pepper, Piper longum L., against phytopathogenic fungi
Sung-Eun Lee; Byeoung-Soo Park; Moo-Key Kim; Won-Sik Choi; Heung-Tae Kim; Kwang-Yun Cho; Sang-Guei Lee; Hoi-Seon Lee
Fungicidal activity of Piper longum L. fruit-derived materials toward six phytopathogenic fungi, Pyricularia oryzae, Rhizoctonia solani, Botrytis cineria, Phytophthora infestans, Puccinia recondita, and Erysiphe graminis, was tested using a whole plant method in vivo. It was compared with synthetic fungicides (chlorothalonil, dichlofluanid and mancozeb) and four commercially available compounds (eugenol, piperine, piperlongumine, and piperettine) derived from P. longum. The response
Podredumbres basales de Gypsophila paniculata (Caryophyllaceae): Agentes causales y su patogenicidad potencial sobre Dianthus caryophyllus (Caryophyllaceae)
Summary: Basal rots of Gypsophila paniculata (Caryophyllaceae). Causal agents and its potential pathogenicity on Dianthus caryophyllus (Caryophyllaceae) The aims of the paper were to determine the causal agents of basal rots of Gypsophila paniculata in Argentina, and to evaluate its possible pathogenicity on Dianthus caryophyllus. Fusarium solani, F. oxysporum, Phytophthora nicotianae, Rhizoctonia solani, F. graminearum, F. verticilloides, F. equiseti and
Registration of TIL:455, TIL:514, and TIL:642, three rice germplasm lines containing introgressed sheath blight resistance alleles
Technology Transfer Automated Retrieval System (TEKTRAN)
There are no genes known to provide complete resistance to rice sheath blight (SB) disease, caused by the fungal pathogen Rhizoctonia solani Kuhn. To create rice varieties resistant to this disease, breeders must combine several genes with small individual impact. Two of the most SB resistant rice ...
Registration of four rice germplasm lines with improved resistance to sheath blight and blast diseases
Technology Transfer Automated Retrieval System (TEKTRAN)
Rice sheath blight (ShB) and blast caused by the fungal pathogens Rhizoctonia solani and Magnaporthe oryzae, respectively, are the two most serious diseases of rice worldwide. Four rice (Oryza sativa L.) germplasm lines designated as LJRIL103 (PI 660982), LJRIL158 (PI 660983), LJRIL186 (PI 660984),...
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight disease, caused by the Rhizoctonia solani fungus, has been the most economically significant rice disease throughout Texas, Louisiana, and Arkansas since the early 1970s. While diseases such as blast and straighthead can also devastate yield, sheath blight disease occurs more consiste...
PGPR: A novel strategy for the control of rice sheath blight disease
Technology Transfer Automated Retrieval System (TEKTRAN)
Sheath blight caused by Rhizoctonia solani is the most important rice disease in Texas, Arkansas, Mississippi and other southern states. Due to the lack of sheath blight resistance in most commonly planted cultivars, southern rice famers apply more than 1 million pounds of fungicides annually to co...
Timing of fungicide sprays to prevent azalea web blight symptoms
Technology Transfer Automated Retrieval System (TEKTRAN)
Azalea web blight is an annual problem on evergreen azalea cultivars grown in containerized nursery production in the southern and eastern United States. Fungicides are the only approach currently used to control Rhizoctonia web blight; however, control is poor in some years because the specifics of...
Cutting propagation of azaleas using hot water treatments to control pathogens
Technology Transfer Automated Retrieval System (TEKTRAN)
Azalea web blight, caused by certain binucleate species of Rhizoctonia, occurs yearly on some azalea cultivars during nursery production in the southern and eastern U.S. Azalea shoots collected for cutting propagation can harbor the pathogen, thus allowing the disease to be perpetuated during the cu...
Brassica juncea seed meal particle size influences chemistry but not soil biology-based suppression of individual agents inciting apple replant disease
Technology Transfer Automated Retrieval System (TEKTRAN)
Apple replant disease is incited by a pathogen complex composed of multiple fungal, oomycete and nematode species. Rhizoctonia solani AG-5 is a significant component of this complex and is suppressed via multiple mechanisms in response to Brassica juncea seed meal (SM) amendment. These mechanisms i...
Two widespread green Neottia species (Orchidaceae) show mycorrhizal preference for Sebacinales in various habitats and ontogenetic stages.
T?šitelová, Tamara; Kotilínek, Milan; Jersáková, Jana; Joly, François-Xavier; Košnar, Ji?í; Tatarenko, Irina; Selosse, Marc-André
Plant dependence on fungal carbon (mycoheterotrophy) evolved repeatedly. In orchids, it is connected with a mycorrhizal shift from rhizoctonia to ectomycorrhizal fungi and a high natural (13)C and (15)N abundance. Some green relatives of mycoheterotrophic species show identical trends, but most of these remain unstudied, blurring our understanding of evolution to mycoheterotrophy. We analysed mycorrhizal associations and (13)C and (15)N biomass content in two green species, Neottia ovata and N. cordata (tribe Neottieae), from a genus comprising green and nongreen (mycoheterotrophic) species. Our study covered 41 European sites, including different meadow and forest habitats and orchid developmental stages. Fungal ITS barcoding and electron microscopy showed that both Neottia species associated mainly with nonectomycorrhizal Sebacinales Clade B, a group of rhizoctonia symbionts of green orchids, regardless of the habitat or growth stage. Few additional rhizoctonias from Ceratobasidiaceae and Tulasnellaceae, and ectomycorrhizal fungi were detected. Isotope abundances did not detect carbon gain from the ectomycorrhizal fungi, suggesting a usual nutrition of rhizoctonia-associated green orchids. Considering associations of related partially or fully mycoheterotrophic species such as Neottia camtschatea or N. nidus-avis with ectomycorrhizal Sebacinales Clade A, we propose that the genus Neottia displays a mycorrhizal preference for Sebacinales and that the association with nonectomycorrhizal Sebacinales Clade B is likely ancestral. Such a change in preference for mycorrhizal associates differing in ecology within the same fungal taxon is rare among orchids. Moreover, the existence of rhizoctonia-associated Neottia spp. challenges the shift to ectomycorrhizal fungi as an ancestral pre-adaptation to mycoheterotrophy in the whole Neottieae. PMID:25612936
The phytoalexins from cauliflower, caulilexins A, B and C: Isolation, structure determination, syntheses and antifungal activity
M. Soledade C. Pedras; Mohammed G. Sarwar; Mojmir Suchy; Adewale M. Adio
Our continuous search for phytoalexins from crucifers led us to examine phytoalexin production in florets of cauliflower (Brassica oleracea var. botrytis) under abiotic (UV light) elicitation. Four known (isalexin, S-(?)-spirobrassinin, 1-methoxybrassitin, brassicanal C) and three new (caulilexins A–C) phytoalexins were isolated. The syntheses and antifungal activity of caulilexins A–C against the economically important pathogenic fungi Leptosphaeria maculans, Rhizoctonia solani and
Rhizobium -Mediated Induction of Phenolics and Plant Growth Promotion in Rice ( Oryza sativa L.)
Ravi P. N. Mishra; Ramesh K. Singh; Hemant K. Jaiswal; Vinod Kumar; Sudarshan Maurya
Qualitative and quantitative estimation of phenolic compounds was done through reverse phase–high performance liquid chromatography\\u000a (RP-HPLC) from different parts (leaf, stem, and root) of rice plants after inoculation with two rhizobial strains, RRE6 (Rhizobium leguminosarum bv. phaseoli) and ANU 843 (R. leguminosarum bv. trifolii) and infection by Rhizoctonia solani. On the basis of their retention time, the major phenolic acids
Effect of acetic acid fumigation on soil-borne fungi and cucumber root rot disease under greenhouse conditions
Farid Abd-El-Kareem
The effect of acetic acid vapour on soil-borne fungi and root rot disease of cucumber plants under greenhouse conditions was studied. Acetic acid vapour at four concentrations was tested against linear growth and spore germination of some soil-borne fungi, in vitro. The most sensitive fungus to acetic acid vapours was Rhizoctonia solani which inhibited at 4 µl l, while Fusarium solani,
Saprophytic and pathogenic behaviour of R. solani AG2-1 (ZG-5) in a soil amended with Diplotaxis tenuifolia or Brassica nigra manures and incubated at different temperatures and soil water content
Titiek Yulianti; K. Sivasithamparam; David W. Turner
The Brassicaceae species Diplotaxis tenuifolia and Brassica nigra contain high concentrations of glucosinolates, the precursors of isothiocyanates (ITCs) that can have biofumigation effects\\u000a in amended soils. In a laboratory experiment, incorporation of these plants as green manures into soil was expected to suppress\\u000a Rhizoctonia solani AG2-1 (ZG5), the causal agent of damping-off in canola (Brassica napus). The manures were incorporated
Potential of butyric acid for control of soil-borne fungal pathogens and nematodes affecting strawberries
M. Browning; D. B. Wallace; C. Dawson; S. R. Alm; J. A. Amador
The effects of butyric acid were evaluated on fungal and nematode endo-parasites of strawberries under controlled laboratory conditions. Verticillium dahliae, Rhizoctonia fragariae, R. solani, Phytophthora fragariae, and a Pythium sp. were killed after a 2-d incubation in butryic acid-treated sand (0.88 and 8.8mg g?1). No fungal growth occurred in the presence of vapors from 0.1 and 1 M butyric acid
Biological control of sheath-blight of rice in india with antagonistic bacteria
T. Vasantha Devi; R. Malar Vizhi; N. Sakthivel; S. S. Gnanamanickam
Strains of fluorescent and nonfluorescent bacteria that were isolated from rice rhizospheres of Southern India and showed\\u000a antagonism towardsRhizoctonia solani were evaluated for biological control of rice sheath-blight (ShB). Efficient strains of bacteria inhibited mycelial growth\\u000a ofR. solani, affected sclerotial viabilityin vitro and protected IR 20 and TKM 9 rice seedlings from infection byR. solani in greenhouse tests. Pretreatment of
Effects of culture parameters on the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4DCP) by selected fungi
T. Vroumsia; R. Steiman; F. Seigle-Murandi; J.-L. Benoit-Guyod
In order to enhance 2,4-D and 2,4-DCP degradation by four selected fungi (Cunningliamella elegans, C. echinnlata, Rhizoctonia solani and Verticillimn lecanii), three culture parameters (initial chemical concentration, amounts of glucose and nitrogen) were varied. The levels of both xenobiotics in the culture media were monitored by HPLC analysis after five days of cultivation. The best results were obtained at low
The influence of bacterial and fungal isolates from the rhizosphere of Tamcot CAMD-E on host response to Phymatotrichum root rot of cotton
Lazo, Gerard Raymond
of certain soil microbes; some commonly mentioned ones are species of Arthrobacter spp. , Pseudomonas spp. , and Chromobacterium spp. (61). Experiments with Fusarium-wilt suppressing soils suggested that competition between saprophytic and pathogenic... rhizosphere, had a 50% reduction in damping-off caused by Rhizoctonia solani (42). In another series of experiments bacterial treatments of carnation were found to reduce the incidence of Fusarium wilt (54). Other modes of protection, such as growth...
Expression of the bacteriophage T4 lysozyme gene in tall fescue confers resistance to gray leaf spot and brown patch diseases
Shujie Dong; H. David Shew; Jianli Lu; Elumalai Sivamani; Eric S. Miller; Rongda Qu
Tall fescue (Festuca arundinacea Schreb.) is an important turf and forage grass species worldwide. Fungal diseases present a major limitation in the maintenance\\u000a of tall fescue lawns, landscapes, and forage fields. Two severe fungal diseases of tall fescue are brown patch, caused by\\u000a Rhizoctonia solani, and gray leaf spot, caused by Magnaporthe grisea. These diseases are often major problems of
Demonstration of antifungal and anti-human immunodeficiency virus reverse transcriptase activities of 6-methoxy-2-benzoxazolinone and antibacterial activity of the pineal indole 5-methoxyindole-3-acetic acid
H. X Wang; T. B Ng
6-Methoxy-2-benzoxazolinone (6-MBOA), a naturally occurring progonadal compound present in grasses with structural resemblance to melatonin, was tested for antifungal activity against Fusarium oxysporum, Rhizoctonia solani and Coprinus comatus. A variety of pineal products was also examined for the sake of comparison, including 5-methoxytryptamine, melatonin, 5-methoxytryptophol, 5-hydroxytryptamine, 5-methoxyindole-3-acetic acid and 5-hydroxytryptophol. The assay for antifungal activity was carried out in Petri
Overexpression of TiERF1 enhances resistance to sharp eyespot in transgenic wheat
Liang Chen; ZengYan Zhang; HongXia Liang; HongXia Liu; L. Du; H. Xu; Z. Xin
Wheat sharp eyespot, primarily caused by a soil-borne fungus Rhizoctonia cerealis, has become one of the most serious diseases of wheat in China. In this study, an ethylene response factor (ERF) gene from a wheat relative Thinopyrum intermedium, TiERF1, was charac- terized further, transgenic wheat lines expressing TiERF1 were developed, and the resistance of the transgenic wheat lines against R.
Evaluation of antifungal potential of Marchantia polymorpha L., Dryopteris filix-mas (L.) Schott and Ephedra foliata Boiss. against phyto fungal pathogens
Neelam Mewari; Padma Kumar
Methanol and flavonoid extracts (free and bound) of Marchantia polymorpha L., Dryopteris filix-mas (L.) Schott and Ephedra foliata Boiss. were screened against three fungal plant pathogens: Alternaria solani, Fusarium oxysporum and Rhizoctonia solani. The extracts from D. filix-mas and E. foliata showed >80% of mycelial inhibition of A. solani whereas M. polymorpha and D. filix-mas (rhizome) completely inhibited the mycelial
Synthesis and biological activities of N-(1,2,4-triazole-4-yl)- N?-(fluorine-containing-phenyl)carbamimidothioates
Dawei Cui; Zhibin Li; Gonghua Song; Xuhong Qian
A series of N-(1,2,4-triazole-4-yl)-N?-(fluorine-containing-phenyl)carbamimidothioates 5a–i were synthesized by reacting 4-amine-1,2,4-trizaole with corresponding aryl isothiocyanates in ethanol at room temperature and, in a subsequent step, with methyl iodide. The antifungal activities of the title compounds against the fungi Rhizoctonia solan and Pyricularia orizae were screened.
Brassica juncea seed meal particle size influences chemistry but not soil biology-based suppression of individual agents inciting apple replant disease
Mark Mazzola; Xiaowen Zhao
Apple replant disease is incited by a pathogen complex composed of multiple fungal, oomycete and nematode species. Rhizoctonia solani AG-5 can be a significant component of this complex and is effectively suppressed via multiple functional mechanisms in response\\u000a to Brassica juncea seed meal (SM) amendment. These mechanisms include those of both a biological and chemical nature. The effect of seed
Induction of DIMBOA accumulation and systemic defense responses as a mechanism of enhanced resistance of mycorrhizal corn ( Zea mays L.) to sheath blight
Yuan Yuan Song; Man Cao; Li Jun Xie; Xiao Ting Liang; Ren Sen Zeng; Yi Juan Su; Jing Hua Huang; Rui Long Wang; Shi Ming Luo
Arbuscular mycorrhizas are the most important symbioses in terrestrial ecosystems and they enhance the plant defense against\\u000a numerous soil-borne pathogenic fungi and nematodes. Two corn (Zea mays) varieties, Gaoyou-115 that is susceptible to sheath blight disease caused by Rhizoctonia solani and Yuenong-9 that is resistant, were used for mycorrhizal inoculation in this study. Pre-inoculation of susceptible Gaoyou-115\\u000a with arbuscular mycorrhizal
Isolation and In Vivo and In Vitro Antifungal Activity of Phenylacetic Acid and Sodium Phenylacetate from Streptomyces humidus
BYUNG KOOK HWANG; SONG WON LIM; BEOM SEOK KIM; JUNG YEOP LEE; S. S. Moon
The antifungal substances SH-1 and SH-2 were isolated from Streptomyces humidus strain S5-55 cultures by various purification procedures and identified as phenylacetic acid and sodium phenylacetate, respectively, based on the nuclear magnetic resonance, electron ionization mass spectral, and inductively coupled plasma mass spectral data. SH-1 and SH-2 completely inhibited the growth of Pythium ultimum, Phytophthora capsici, Rhizoctonia solani, Saccharomyces cerevisiae,
Seedling disease of sorghum [Sorghum bicolor (L.) Moench]: epidemiology, etiology and resistance
Forbes, Gregory Allan
diseased tissue and reports in the literature, Fusarium moniliforme, Rhizoctonia solani and Pfthium arrhenomanes were chosen for pathogenicity tests. NFS and PSF were infested at 3 inoculum densities (1/10, 1/100 and iv I 1/1000; V/V) with one isolate... and particularly of the mesocotyl. In a short time after the red condition appeared, the tissue began to shrivel and darken. " Diseased plants were sometimes killed, but other plants often recovered in the field. The environmental conditions associated...
Penn State: Plant Pathology Fact Sheets
NSDL National Science Digital Library
This selection of online fact sheets concerned with plant diseases was compiled by Professor Gary W. Moorman, a Professor of Plant Pathology at Penn State. The concise fact sheets address "common diseases of plants frequently grown in greenhouses, interiorscapes, and in outdoor landscapes and nurseries in the northeastern U.S." The sheets are organized under categories for Woody Ornamental, and Floral and Foliage Plants, as well as a General Information category. Factsheets address such diseases as Bacterial Leaf Scorch, Pythium Root Rot, Botrytis Blight, Rhizoctonia, and more. There are sheets for a wide variety of plants and trees including Iris, Tulip, Maple, and Oak, to name a few.
Design, synthesis, anti-TMV, fungicidal, and insecticidal activity evaluation of 1,2,3,4-tetrahydro-?-carboline-3-carboxylic acid derivatives based on virus inhibitors of plant sources.
Song, Hong-jian; Liu, Yong-xian; Liu, Yu-xiu; Huang, Yuan-qiong; Li, Yong-qiang; Wang, Qing-min
By drawing the creation ideas of botanical pesticides, a series of tetrahydro-?-carboline-3-carboxylic acid derivatives were designed and synthesized, and first evaluated for their anti-TMV, fungicidal and insecticidal activities. Most of these derivatives exhibited good antiviral activity against TMV both in vitro and in vivo. Especially, the activities of compounds 8 and 15 in vivo were higher than that of ribavirin. The compound 8 exhibited more than 70% fungicidal activities against Cercospora arachidicola Hori, Alternaria solani, Bipolaris maydis, and Rhizoctonia solani at 50mg/kg, compounds 16 and 20 exhibited more than 60% insecticidal activities against Mythimna separate and Ostrinia nubilalis. PMID:25442317
Synthesis and characterization of some acyl thiourea derivatives of chitosan and their biocidal activities.
Elkholy, Said S; Salem, Hend A; Eweis, Mohamed; Elsabee, Maher Z
Three acyl derivatives of chitosan (CS) with different side chains were synthesized and their structures were characterized. Their swelling behavior was investigated. The antifungal behavior of these chitosan derivatives was investigated in vitro on the mycelial growth, sporulation and germination of conidia or sclerotia of the sugar-beet pathogens, Rhizoctonia solani K"uhn (AG2-2) and Sclerotium rolfsii Sacc. All the prepared derivatives had a significant inhibiting effect on the different stages of development on the germination of conidia or sclerotia of all the investigated fungi. In the absence of chitosan and its derivative, R. solani exhibited the fastest growth of the fungi studied. PMID:25002014
Penn State: Plant Disease Fact Sheets
NSDL National Science Digital Library
This selection of online fact sheets concerned with plant diseases was compiled by Professor Gary W. Moorman, a Professor of Plant Pathology at Penn State. The concise fact sheets address "common diseases of plants frequently grown in greenhouses, interiorscapes, and in outdoor landscapes and nurseries in the northeastern U.S." The sheets are organized under categories for Woody Ornamental, and Floral and Foliage Plants, as well as a General Information category. Factsheets address such diseases as Bacterial Leaf Scorch, Pythium Root Rot, Botrytis Blight, Rhizoctonia, and more. There are sheets for a wide variety of plants and trees including Iris, Tulip, Maple, and Oak, to name a few.
The use of natural bio-agents for the control of cotton phytopathogens.
Mannanov, R N
The use of natural antagonists as means of pre-sowing seed treatment showed high biological efficacy by improving seed germination, growth and productivity of cotton plants, and by decreasing infection by major cotton pathogens: Xanthomonas malvacearum, Rhizoctonia solani, Fusarium oxysporum f. sp. vasinfectum, Verticillium dahliae. Studies of anti-microbial properties of antagonists revealed significant inhibitory activity of Bacillus subtilis strains and their metabolites against cotton pathogens. Obtained results prove the prospective from the use of B. subtilis for developing complex, ecological products for biological control of cotton and other agricultural plants. PMID:15954583
Antimicrobial activity of some coumarin containing herbal plants growing in Finland.
Ojala, T; Remes, S; Haansuu, P; Vuorela, H; Hiltunen, R; Haahtela, K; Vuorela, P
Antimicrobial screening against selected Gram-positive and Gram-negative bacteria, yeasts, mold, as well as plant pathogenic fungi, with emphasis on method optimization was carried out on methanol extracts prepared from seven plants grown in Finland. Sensitivity to the extracts was found to vary considerably among the micro-organisms, the extract from Petroselinum crispum and Ruta graveolens showing the highest toxicity against Rhizoctonia solani. The growth of Heterobasidium annosum was inhibited, whereas that of Phytophtora (cactorum) was promoted by all the extracts. The antibacterial and antifungal activities of six natural coumarin compounds were weak, except for the inhibitory effect against Fusarium culmorum. PMID:11025169
Cerinolactone, a hydroxy-lactone derivative from Trichoderma cerinum.
Vinale, Francesco; Girona, Isabel Arjona; Nigro, Marco; Mazzei, Pierluigi; Piccolo, Alessandro; Ruocco, Michelina; Woo, Sheridan; Rosa, David Ruano; Herrera, Carlos López; Lorito, Matteo
A novel metabolite, 3-hydroxy-5-(6-isopropyl-3-methylene-3,4,4a,5,6,7,8,8a-octahydronaphthalen-2-yl)dihydrofuran-2-one, trivially named cerinolactone (1), has been isolated from culture filtrates of Trichoderma cerinum together with three known butenolides containing the 3,4-dialkylfuran-2(5H)-one nucleus, harzianolide (2), T39butenolide (3), and dehydroharzianolide (4). The structure of 1 was determined by spectroscopic methods, including UV, MS, and 1D and 2D NMR analyses. In vitro tests with the purified compound exhibited activity against Pythium ultimum, Rhizoctonia solani, and Botrytis cinerea. PMID:22196692
Morphological characteristics and pathogenicity of fungi associated with Roselle (Hibiscus Sabdariffa) diseases in Penang, Malaysia.
Eslaminejad, Touba; Zakaria, Maziah
Roselle, or Jamaica sorrel (Hibiscus sabdariffa) is a popular vegetable in many tropical regions, cultivated for its leaves, seeds, stems and calyces which, the dried calyces are used to prepare tea, syrup, jams and jellies and as beverages. The main objectives of this study were to identify and characterise fungal pathogens associated with Roselle diseases based on their morphological and cultural characteristics and to determine the pathogenicity of four fungi infecting Roselle seedlings, namely Phoma exigua, Fusarium nygamai, Fusarium tgcq and Rhizoctonia solani in Penang. A total of 200 fungal isolates were obtained from 90 samples of symptomatic Roselle tissues. The isolates were identified based on cultural and morphological characteristics, as well as their pathogenicity. The fungal pathogen most frequently isolated was P. exigua (present in 45% of the samples), followed by F. nygamai (25%), Rhizoctonia solani (19%) and F. camptoceras (11%). Pathogenicity tests showed that P. exigua, F. nygamai, F. camptoceras and R. solani were able to infect both wounded and unwounded seedlings with different degrees of severity as indicated by the Disease severity (DS). R. solani was the most pathogenic fungus affecting both wounded and unwounded Roselle seedlings, followed by P. exigua that was highly pathogenic on wounded seedlings. F. nygamai was less pathogenic while the least pathogenic fungus was F. camptoceras, infecting only the unwounded seedlings but, surprisingly, not the wounded plants. PMID:21839160
Antimicrobial action effect and stability of nanosized silica hybrid Ag complex.
Kim, Hwa-Jung; Park, Hae-Jun; Choi, Seong-Ho
Nanosized silica hybrid silver complex (NSS) showing strong antifungal activity, in which nanosilver (nano-Ag) was bound to silica (SiO2) molecules, was synthesized via gamma-irradiation at room temperature. NSS was characterized via field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDXS), ultraviolet-visible (UV-Vis) spectrophotometer, and thermogravimetric analysis (TGA). The FESEM images and EDXS data showed that well-dispersed 3-to-10-nm Ag nanoparticles (core part) were loaded onto the outer parts of 5-to-20 nm SiO2 nanoparticles. The antifungal efficiency of NSS was evaluated against Rhizoctonia solani, Botrytis cinerea, and Colletotrichum gloeosporioides. In the case of Rhizoctonia solani, the growth rate was decreased typically by more than 90% at a 6 microg/ml concentration of NSS as a medium additive. The antifungal-action mechanism was investigated via transmission electron microscopy (TEM) analysis of the NSS treatment against Botrytis cinerea. The stability and antimicrobial activity of NSS were determined, using the plate culture method, from several water samples containing NSS after 7-day NSS treatment. Moreover, the NSS solution maintained stable antifungal activity for at least 24 mos. These results suggest that NSS, an environment-friendly nanomaterial, can be used as strongly effective growth inhibitor of various microorganisms, making it applicable to diverse antimicrobial-control systems. PMID:22121607
Enhancing plant disease suppression by Burkholderia vietnamiensis through chromosomal integration of Bacillus subtilis chitinase gene chi113.
Zhang, Xinjian; Huang, Yujie; Harvey, Paul R; Ren, Yan; Zhang, Guangzhi; Zhou, Hongzi; Yang, Hetong
Burkholderia vietnamiensis P418 is a plant growth-promoting rhizobacteria. A chitinase gene from Bacillus subtilis was cloned and stably integrated into the chromosome of using the transposon delivery vector, pUTkm1. Chitinase activity was detected in recombinant P418-37 but not in wild type P418. Recombinant P418-37 retained the in vitro growth rate, N(2)-fixation and phosphate and potassium-solubilizing characteristics of the wild type. P418-37 significantly (P < 0.05) increased in vitro inhibition of the plant pathogenic fungi Rhizoctonia solani, Fusarium oxysporum f.sp. vasinfectum, Rhizoctonia cerealis, Bipolaris sorokiniana, Verticillium dahliae and Gaeumannomyces graminis var. tritici compared with P418. In planta disease suppression assays indicated that P418-37 significantly (P < 0.05) enhanced suppression of wheat sheath blight (R. cerealis), cotton Fusarium wilt (F. oxysporium f.sp. vasinfectum) and tomato gray mould (Botrytis cinerea), relative to the wild type. PMID:21972146
A metabolic profiling strategy for the dissection of plant defense against fungal pathogens.
Aliferis, Konstantinos A; Faubert, Denis; Jabaji, Suha
Here we present a metabolic profiling strategy employing direct infusion Orbitrap mass spectrometry (MS) and gas chromatography-mass spectrometry (GC/MS) for the monitoring of soybean's (Glycine max L.) global metabolism regulation in response to Rhizoctonia solani infection in a time-course. Key elements in the approach are the construction of a comprehensive metabolite library for soybean, which accelerates the steps of metabolite identification and biological interpretation of results, and bioinformatics tools for the visualization and analysis of its metabolome. The study of metabolic networks revealed that infection results in the mobilization of carbohydrates, disturbance of the amino acid pool, and activation of isoflavonoid, ?-linolenate, and phenylpropanoid biosynthetic pathways of the plant. Components of these pathways include phytoalexins, coumarins, flavonoids, signaling molecules, and hormones, many of which exhibit antioxidant properties and bioactivity helping the plant to counterattack the pathogen's invasion. Unraveling the biochemical mechanism operating during soybean-Rhizoctonia interaction, in addition to its significance towards the understanding of the plant's metabolism regulation under biotic stress, provides valuable insights with potential for applications in biotechnology, crop breeding, and agrochemical and food industries. PMID:25369450
Asymmetric diphenol formation by a fungal laccase.
Bollag, J M; Liu, S Y; Minard, R D
A laccase isolated from the fungus Rhizoctonia praticola catalyzed the cross-coupling of two differently halogenated phenols. When 2,4-dichlorophenol and 4-bromo-2-chlorophenol were incubated together with the enzyme, three dimers were formed and isolated by thin-layer chromatography. The molecular weights of these compounds were determined by mass spectrometry as 322, 410, and 366, which correspond with the respective dimers of each of the phenols and with a hybrid formed from both, tentatively assigned the structure 3,3',5'-trichloro-5-bromo-2,2'-diphenol. Gas chromatography-mass spectrometry analysis of these products and of their methylated derivatives lent support to these structural assignments. PMID:114116
Isolation and in vivo and in vitro antifungal activity of phenylacetic acid and sodium phenylacetate from Streptomyces humidus.
Hwang, B K; Lim, S W; Kim, B S; Lee, J Y; Moon, S S
The antifungal substances SH-1 and SH-2 were isolated from Streptomyces humidus strain S5-55 cultures by various purification procedures and identified as phenylacetic acid and sodium phenylacetate, respectively, based on the nuclear magnetic resonance, electron ionization mass spectral, and inductively coupled plasma mass spectral data. SH-1 and SH-2 completely inhibited the growth of Pythium ultimum, Phytophthora capsici, Rhizoctonia solani, Saccharomyces cerevisiae, and Pseudomonas syringae pv. syringae at concentrations from 10 to 50 microg/ml. The two compounds were as effective as the commercial fungicide metalaxyl in inhibiting spore germination and hyphal growth of P. capsici. However, the in vivo control efficacies of the two antifungal compounds against P. capsici infection on pepper plants were similar to those of H(3)PO(3) and fosetyl-AI but less than that of metalaxyl. PMID:11472958
Disease-reducing effect of Chromolaena odorata extract on sheath blight and other rice diseases.
Khoa, Nguyen ?ac; Thuy, Phan Thi Hong; Thuy, Tran Thi Thu; Collinge, David B; Jřrgensen, Hans Jřrgen Lyngs
Sheath blight caused by Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is a major cause of crop loss in intensive rice production systems. No economically viable control methods have been developed. We screened aqueous extracts of common herbal plants that could reduce sheath blight lesions and found that foliar spraying and seed soaking application of extracts of either fresh or dried leaves of Chromolaena odorata gave up to 68% reduction in sheath blight lesion lengths under controlled and semi-field conditions. The observed reductions were not dependent on growth conditions of C. odorata and rice cultivar. The effect was observed until 21 days after inoculation and was not dependent on microbial activity. Under semi-field conditions, extracts also reduced severity of other important rice diseases, i.e., blast (Pyricularia oryzae) using foliar spray (up to 45%), brown spot (Bipolaris oryzae) using seed treatment (up to 57%), and bacterial blight (Xanthomonas oryzae pv. oryzae) using both application methods (up to 50%). PMID:20839964
Zoosporicidal metabolites from an endophytic fungus Cryptosporiopsis sp. of Zanthoxylum leprieurii.
Talontsi, Ferdinand Mouafo; Facey, Petrea; Tatong, Michel D Kongue; Tofazzal Islam, M; Frauendorf, Holm; Draeger, Siegfried; Tiedemann, Andreas von; Laatsch, Hartmut
Two polyketides, cryptosporiopsin A (1) and hydroxypropan-2',3'-diol orsellinate (3), and a natural cyclic pentapeptide (4), together with two known compounds were isolated from the culture of Cryptosporiopsis sp., an endophytic fungus from leaves and branches of Zanthoxylum leprieurii (Rutaceae). The structures of these metabolites were elucidated on the basis of their spectroscopic and spectrometric data. Cryptosporiopsin A and the other metabolites exhibited motility inhibitory and lytic activities against zoospores of the grapevine downy mildew pathogen Plasmopara viticola at 10-25?g/mL. In addition, the isolated compounds displayed potent inhibitory activity against mycelial growth of two other peronosporomycete phytopathogens, Pythium ultimum, Aphanomyces cochlioides and a basidiomycetous fungus Rhizoctonia solani. Weak cytotoxic activity on brine shrimp larvae was observed. PMID:22883958
Development of a Selective Medium for the Fungal Pathogen Cylindrocarpon destructans Using Radicicol.
Kang, Yunhee; Lee, Seung-Ho; Lee, Jungkwan
The soil-borne ascomycete fungus Cylindrocarpon destructans causes ginseng root rot disease and produces various secondary metabolites such as brefeldin A and radicicol. The slow growth of this fungus compared with other plant pathogenic and saprophytic fungi in soil disturbs isolation of this fungus from soil and infected ginseng. In this study, we developed a selective medium for C. destructans using radicicol produced by this fungus. Supplementing 50 mg/L of radicicol to medium inhibited the mycelia growth of other fungi including Botrytis cinerea, Rhizoctonia solani and Alternaria panax, but did not affect the growth of C. destructans. In addition, conidia germination of other fungal species except for C. destructans was inhibited in submerged culture supplemented with radicicol. This medium provides a very efficient tool for isolating C. destructans and also can be used as an enrichment medium for this fungus. PMID:25506308
Mn(II) and Cu(II) complexes of a bidentate Schiff's base ligand: Spectral, thermal, molecular modelling and mycological studies
NASA Astrophysics Data System (ADS)
Tyagi, Monika; Chandra, Sulekh; Tyagi, Prateek
Complexes of manganese(II) and copper(II) of general composition M(L)2X2 have been synthesized [L = 2-acetyl thiophene thiosemicarbazone and X = Cl- and NO3-]. The elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, UV, NMR and EPR spectral studies of the compounds led to the conclusion that the ligand acts as a bidentate manner. The Schiff's base ligand forms hexacoordinated complexes having octahedral geometry for Mn(II) and tetragonal geometry for Cu(II) complexes. The thermal studies suggested that the complexes are more stable as compared to ligand. In molecular modelling the geometries of Schiff's base and metal complexes were fully optimized with respect to the energy using the 6-31g(d,p) basis set. The mycological studies of the compounds were examined against the plant pathogenic fungi i.e. Rhizoctonia bataticola, Macrophomina phaseolina, Fusarium odum.
Synthesis and antifungal activity of the derivatives of novel pyrazole carboxamide and isoxazolol pyrazole carboxylate.
Sun, Jialong; Zhou, Yuanming
A series of pyrazole carboxamide and isoxazolol pyrazole carboxylate derivatives were designed and synthesized in this study. The structures of the compounds were elucidated based on spectral data (infrared, proton nuclear magnetic resonance and mass spectroscopy). Then, all of the compounds were bioassayed in vitro against four types of phytopathogenic fungi (Alternaria porri, Marssonina coronaria, Cercospora petroselini and Rhizoctonia solani) using the mycelium growth inhibition method. The results showed that some of the synthesized pyrazole carboxamides displayed notable antifungal activity. The isoxazole pyrazole carboxylate 7ai exhibited significant antifungal activity against R. solani, with an EC50 value of 0.37 ?g/mL. Nonetheless, this value was lower than that of the commercial fungicide, carbendazol. PMID:25759955
Spectral and thermal studies with anti-fungal aspects of some organotin(IV) complexes with nitrogen and sulphur donor ligands derived from 2-phenylethylamine
NASA Astrophysics Data System (ADS)
Singh, Rajeev; Kaushik, N. K.
Some complexes of 2-phenylethyl dithiocarbamate, thiohydrazides and thiodiamines with dibenzyltin(IV) chloride, tribenzyltin(IV) chloride and di( para-chlorobenzyl)tin(IV) dichloride have been synthesized and investigated in 1:2 and 1:1 molar ratio. The dithiocarbamate ligand act as monoanionic bidentate and thiohydrazide, thiodiamines act as neutral bidentate ligand. The synthesized complexes have been characterized by elemental analysis and molecular weight determination studies and their bonding pattern suggested on the basis of electronic, infrared, 1H and 13C NMR spectroscopy. Using thermogravimetric (TG) and differential thermal analysis (DTA) various thermodynamic and kinetic parameters viz. reaction order ( n), apparent activation energy ( Ea), apparent activation entropy ( S#) and heat of reaction (? H) have been calculated and correlated with the structural aspects for solid-state decomposition of complexes. The ligands and their tin complexes have also been screened for their fungitoxicity activity against Rhizoctonia solanii and Sclerotium rolfsii and their ED 50 values calculated.
Organotin(IV) complexes of thiohydrazones: synthesis, characterization and antifungal study
NASA Astrophysics Data System (ADS)
Mishra, A. K.; Manav, N.; Kaushik, N. K.
Some new organotin(IV) complexes with salicylaldehyde aniline- N-thiohydrazone (L 1) and cinamaldehyde aniline- N-thiohydrazone (L 2) of the type ( p-ClC 6H 4) 3Sn[L] Cl and ( p-ClC 6H 4) 2Sn[L]Cl 2 have been synthesized (where L = L 1 and L 2). The complexes and ligands were characterized by elemental analysis and spectral (UV-vis, IR and 1H NMR) studies. In all the complexes, ligands act as bidentate, coordination through sulphur and azomethane nitrogen. Complexes are 1:1 metal ligands complexes. Antifungal studies of some complexes against Rhizoctonia bataticola fungal strain have been carried out.
Novonestmycins A and B, two new 32-membered bioactive macrolides from Streptomyces phytohabitans HBERC-20821.
Wan, Zhongyi; Fang, Wei; Shi, Liqiao; Wang, Kaimei; Zhang, Yani; Zhang, Zhigang; Wu, Zhaoyuan; Yang, Ziwen; Gu, Yucheng
Two new 32-membered macrolide compounds, named Novonestmycins A (1) and B (2), were isolated from the soil strain Streptomyces phytohabitans HBERC-20821. Their structures were elucidated by using spectroscopic methods, including 1D, 2D-NMR and MS spectrometry. The two compounds showed strong activities against the phytophathogenic fungi Corynespora cassiicola, Rhizoctonia solani and Septoria nodorum, with MIC values of 0.78, 0.39 and 0.78??g?ml(-1), respectively. In addition, the two compounds exhibited potent inhibitory activities against four different human tumor cell lines as well as one 5-FU-resistant human hepatocellular carcinoma cell line, with IC50 of 0.15-0.48??g?ml(-1) and 0.24-1.34??g?ml(-1), respectively. PMID:25204346
Synthesis and antifungal activity of 1,2,3-triazole phenylhydrazone derivatives.
Dai, Zhi-Cheng; Chen, Yong-Fei; Zhang, Mao; Li, Sheng-Kun; Yang, Ting-Ting; Shen, Li; Wang, Jian-Xin; Qian, Shao-Song; Zhu, Hai-Liang; Ye, Yong-Hao
A series of 1,2,3-triazole phenylhydrazone derivatives were designed and synthesized as antifungal agents. Their structures were determined based on (1)H-NMR spectroscopy, MS, elemental analysis and X-ray single-crystal diffraction. The antifungal activities were evaluated against four phytopathogenic fungi including Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum and Phytophthora capsici, by the mycelium growth inhibition method in vitro. Compound 5p exhibited significant anti-phytopathogenic activity, with the EC50 values of 0.18, 2.28, 1.01, and 1.85 ?g mL(-1), respectively. In vivo testing demonstrated that 5p was effective in the control of rice sheath blight, rape sclerotinia rot and fusarium head blight. A 3D-QSAR model was built for a systematic SAR profile to explore more potent 1,2,3-triazole phenylhydrazone analogs as novel fungicides. PMID:25374053
Study on Mutagenic Breeding of Bacillus Subtilis and Properties of Its Antifungal Substances
NASA Astrophysics Data System (ADS)
Liu, Jing; Yao, Jianming
Bacillus subtitles JA isolated by our laboratory produced a large amount of antifungal substances, which had strong inhibitory activity against various plant pathogenic fungi, such as Rhizoctonia solani, Fusarium graminearum and so on. Ion beam implantation as a new mutagenic methods was applied in our studay. After B. subtitles JA was implanted by N+ ions, a strain designated as B. subtitles JA-026 was screened and obtained, which had a higher ability to produce those antifungal substances. A series of experiments indicated that the antifungal substances were thermostable and partially sensitive to proteinases K and tryproteinase. When the fermentating broth was fractionated with ammonium sulphate of a final saturation of 70%, the precipitate-enhanced inhibitory activity while the supernatant lost this activity. It appeared that the antifungal substances were likely to be protein.
Optimization for rapid synthesis of silver nanoparticles and its effect on phytopathogenic fungi
NASA Astrophysics Data System (ADS)
Krishnaraj, C.; Ramachandran, R.; Mohan, K.; Kalaichelvan, P. T.
In this present study, silver nanoparticles were synthesized by green chemistry approach using Acalypha indica leaf extract as reducing agents. The reaction medium employed in the synthesis process was optimized to attain better yield, controlled size and stability. Further, the biosynthesized silver nanoparticles were conformed through UV-vis spectrum, XRD and HR-TEM analyses. Different concentration of silver nanoparticles were tested to know the inhibitory effect of fungal plant pathogens namely Alternaria alternata, Sclerotinia sclerotiorum, Macrophomina phaseolina, Rhizoctonia solani, Botrytis cinerea and Curvularia lunata. Interestingly, 15 mg concentration of silver nanoparticles showed excellent inhibitory activity against all the tested pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi.
Isolation and characterization of genetic variability in bacteria with ?-hemolytic and antifungal activity isolated from the rhizosphere of Medicago truncatula plants.
Hernández-Salmerón, J E; Prieto-Barajas, C M; Valencia-Cantero, E; Moreno-Hagelsieb, G; Santoyo, G
In the present study, we analyzed the frequency of hemolytic and antifungal activities in bacterial isolates from the rhizosphere of Medicago truncatula plants. Of the 2000 bacterial colonies, 96 showed ?-hemolytic activities (frequency, 4.8 x 10(-2)). Hemolytic isolates were analyzed for their genetic diversity by using random amplification of polymorphic DNA, yielding 88 haplotypes. The similarity coefficient of Nei and Li showed a polymorphic diversity ranging from 0.3 to 1. Additionally, 8 of the hemolytic isolates showed antifungal activity toward plant pathogens, Diaporthe phaseolorum, Colletotrichum acutatum, Rhizoctonia solani, and Fusarium oxysporum. The 16S ribosomal sequencing analysis showed that antagonistic bacterial isolates corresponded to Bacillus subtilis (UM15, UM33, UM42, UM49, UM52, and UM91), Bacillus pumilus (UM24), and Bacillus licheniformis (UM88). The present results revealed a higher genetic diversity among hemolytic isolates compared to that of isolates with antifungal action. PMID:25062484
Isolation and structure elucidation of three neo-clerodane diterpenes from Teucrium fruticans L. (LABIATAE).
Coll, Josep; Tandrón, Yudelsy
Recently, the isolation from Teucrium fruticans of neo-clerodanes, namely 7beta-hydroxyfruticolone, 11-hydroxyfruticolone, deacetylfruticolone and 6-acetyl-10-hydroxyteucjaponin B, in addition to fruticolone, isofruticolone and 8beta-hydroxyfruticolone (three out of the four previously reported ones), and 6-acetylteucjaponin B (isolated from T. scordium and T. grisebachii) was reported. Minor compounds presumably of neo-clerodane nature were shown by HPLC analysis on a new extract. Three new compounds, difuranofruticol, deoxyfruticolone and 10-hydroxyteucjaponin B, and the known 7,8-didehydrofruticolone were unambiguously elucidated based on extensive NMR spectral studies (one- and two-dimensional experiments). The compounds were assayed for their antifeedant activity against Spodoptera littoralis and for their antifungal activity against Rhizoctonia solani. Compounds 9-11 showed low antifeedant activity and the feeding ratio of 12 was moderate-low. None of the tested compounds displayed significant activity against R. solani. PMID:16122769
Effect of three nematicides on the growth of some phytopathogenic bacteria and fungi.
El-Khadem, M; Mehiar, F; Embabi, M S
The effect of three nematicides, aldicarb, fensulfothion, and phenamiphos at four concentrations (1, 5, 25, and 125 ppm) was tested on the growth of five bacteria, Agrobacterium tumefaciens, Corynebacterium fascians, Erwinia carotovora, Pseudomonas solanacearum, and Streptomyces scabies and four fungi, Fusarium oxysporum f. sp. vasinfectum, Fusarium solani, Rhizoctonia solani, and Sclerotium bataticola. Of the bacteria, P. solanacearum was most affected by the chemicals at all concentrations, while E. carotovora was least affected. Fensulfothion was generally the most effective nematicide on the bacteria tested, while phenamiphos was the least effective. Similarly, the effect of the chemicals on the fungi tested varied greatly. F. solani and R. solani were generally most affected, followed by F. oxysporum, while S. bataticola was least affected. Of the chemicals tested, phenamiphos was generally the most effective, followed by fensulfothion, while aldicarb was the least effective. PMID:143857
Demonstration of antifungal and anti-human immunodeficiency virus reverse transcriptase activities of 6-methoxy-2-benzoxazolinone and antibacterial activity of the pineal indole 5-methoxyindole-3-acetic acid.
Wang, H X; Ng, T B
6-methoxy-2-benzoxazolinone (6-MBOA), a naturally occurring progonadal compound present in grasses with structural resemblance to melatonin, was tested for antifungal activity against Fusarium oxysporum, Rhizoctonia solani and Coprinus comatus. A variety of pineal products was also examined for the sake of comparison, including 5-methoxytryptamine, melatonin, 5-methoxytryptophol, 5-hydroxytryptamine, 5-methoxyindole-3-acetic acid and 5-hydroxytryptophol. The assay for antifungal activity was carried out in Petri plates containing potato dextrose agar. It was found that 6-MBOA most potently inhibited the growth of C. comatus, R. solani and F. oxysporum. When 6-MBOA and pineal indoles were tested for antibacterial activity against the bacterium Agrobacterium tumefaciens, 5-methoxyindole-3-acetic acid was found to be the most potent. 6-MBOA most potently inhibited human immunodeficiency virus-1 reverse transcriptase. PMID:12106902
Isolation of a New Mexican Strain of Bacillus subtilis with Antifungal and Antibacterial Activities
Basurto-Cadena, M. G. L.; Vázquez-Arista, M.; García-Jiménez, J.; Salcedo-Hernández, R.; Bideshi, D. K.; Barboza-Corona, J. E.
Although several strains of B. subtilis with antifungal activity have been isolated worldwide, to date there are no published reports regarding the isolation of a native B. subtilis strain from strawberry plants in Mexico. A native bacterium (Bacillus subtilis 21) demonstrated in vitro antagonistic activity against different plant pathogenic fungi. Under greenhouse conditions, it was shown that plants infected with Rhizoctonia solani and Fusarium verticillioides and treated with B. subtilis 21 produced augment in the number of leaves per plant and an increment in the length of healthy leaves in comparison with untreated plants. In addition, B. subtilis 21 showed activity against pathogenic bacteria. Secreted proteins by B. subtilis 21 were studied, detecting the presence of proteases and bacteriocin-like inhibitor substances that could be implicated in its antagonistic activity. Chitinases and zwittermicin production could not be detected. Then, B. subtilis 21 could potentially be used to control phytopathogenic fungi that infect strawberry plants. PMID:22593682
Isolation and In Vivo and In Vitro Antifungal Activity of Phenylacetic Acid and Sodium Phenylacetate from Streptomyces humidus
Hwang, Byung Kook; Lim, Song Won; Kim, Beom Seok; Lee, Jung Yeop; Moon, Surk Sik
The antifungal substances SH-1 and SH-2 were isolated from Streptomyces humidus strain S5-55 cultures by various purification procedures and identified as phenylacetic acid and sodium phenylacetate, respectively, based on the nuclear magnetic resonance, electron ionization mass spectral, and inductively coupled plasma mass spectral data. SH-1 and SH-2 completely inhibited the growth of Pythium ultimum, Phytophthora capsici, Rhizoctonia solani, Saccharomyces cerevisiae, and Pseudomonas syringae pv. syringae at concentrations from 10 to 50 ?g/ml. The two compounds were as effective as the commercial fungicide metalaxyl in inhibiting spore germination and hyphal growth of P. capsici. However, the in vivo control efficacies of the two antifungal compounds against P. capsici infection on pepper plants were similar to those of H3PO3 and fosetyl-AI but less than that of metalaxyl. PMID:11472958
The evolution and pathogenic mechanisms of the rice sheath blight pathogen
Zheng, Aiping; Lin, Runmao; Zhang, Danhua; Qin, Peigang; Xu, Lizhi; Ai, Peng; Ding, Lei; Wang, Yanran; Chen, Yao; Liu, Yao; Sun, Zhigang; Feng, Haitao; Liang, Xiaoxing; Fu, Rongtao; Tang, Changqing; Li, Qiao; Zhang, Jing; Xie, Zelin; Deng, Qiming; Li, Shuangcheng; Wang, Shiquan; Zhu, Jun; Wang, Lingxia; Liu, Huainian; Li, Ping
Rhizoctonia solani is a major fungal pathogen of rice (Oryza sativa L.) that causes great yield losses in all rice-growing regions of the world. Here we report the draft genome sequence of the rice sheath blight disease pathogen, R. solani AG1 IA, assembled using next-generation Illumina Genome Analyser sequencing technologies. The genome encodes a large and diverse set of secreted proteins, enzymes of primary and secondary metabolism, carbohydrate-active enzymes, and transporters, which probably reflect an exclusive necrotrophic lifestyle. We find few repetitive elements, a closer relationship to Agaricomycotina among Basidiomycetes, and expand protein domains and families. Among the 25 candidate pathogen effectors identified according to their functionality and evolution, we validate 3 that trigger crop defence responses; hence we reveal the exclusive expression patterns of the pathogenic determinants during host infection. PMID:23361014
Production, purification, and characterization of antifungal metabolite from Pseudomonas aeruginosa SD12, a new strain obtained from tannery waste polluted soil.
Dharni, Seema; Alam, Mansoor; Kalani, Komal; Abdul-Khaliq; Samad, Abdul; Srivastava, Santosh Kumar; Patra, Dharani Dhar
A new strain, SD12, was isolated from tannery waste polluted soil and identified as Pseudomonas aeruginosa on the basis of phenotypic traits and by comparison of 16S rRNA sequences. This bacterium exhibited broad-spectrum antagonistic activity against phytopathogenic fungi. The strain produced phosphatases, cellulases, proteases, pectinases, and HCN and also retained its ability to produce hydroxamate-type siderophore. A bioactive metabolite was isolated from P. aeruginosa SD12 and was characterized as 1-hydroxyphenazine ((1-OH-PHZ) by nuclear magnetic resonance (NMR) spectral analysis. The strain was used as a biocontrol agent against root rot and wilt disease of pyrethrum caused by Rhizoctonia solani. The stain is also reported to increase the growth and biomass of Plantago ovata. The purified compound, 1-hydroxyphenazine, also showed broad-spectrum antagonistic activity towards a range of phytopathogenic fungi, which is the first report of its kind. PMID:22561863
Effects of elevated CO2 on biomass and fungi associated with two ecotypes of ragweed (Ambrosia artemisiifolia L.).
Runion, G Brett; Prior, Stephen A; Price, Andrew J; McElroy, J Scott; Torbert, H Allen
Herbicide resistant weed populations have developed due to the repeated application of herbicides. Elevated concentrations of atmospheric CO2 can have positive effects on weed growth, but how rising CO2 might affect herbicide resistant weeds is not known. Ragweed (Ambrosia artemisiifolia L.) ecotypes known to be resistant or susceptible to glyphosate herbicide were exposed to either ambient or elevated (ambient +200 ? mol mol(-1)) concentrations of CO2 in open top chambers. Plants were harvested following 8 weeks of CO2 exposure; at this time, they had begun to exhibit disease symptoms including spots on leaves and stems. Elevated CO2 significantly increased top, root, and total plant biomass. Also, glyphosate resistant plants had significantly greater top, root, and total biomass than plants susceptible to the herbicide. There were no significant CO2 by ecotype interactions. Fungi from 13 genera were associated with ragweed, several of which can be either pathogens (i.e., Alternaria, Fusarium, Rhizoctonia), aiding the decline in health of the ragweed plants, or saprophytes existing on dead plant tissues. The common foliar disease powdery mildew was significantly higher on susceptible compared with resistant ragweed. Susceptible plants also showed an increased frequency of Rhizoctonia on leaves and Alternaria on stems; however, Fusarium occurred more frequently on resistant ragweed leaves. Fungi were not affected by CO2 concentration or its interaction with ecotype. This study reports the first information on the effects of elevated CO2 on growth of herbicide resistant weeds. This is also the first study examining the impact of herbicide resistance and elevated CO2 on fungi associated with weeds. What effects herbicide resistance might have on plant diseases and how rising atmospheric CO2 might impact these effects needs to be addressed, not only with important weeds but also with crops. PMID:25309569
Effects of elevated CO2 on biomass and fungi associated with two ecotypes of ragweed (Ambrosia artemisiifolia L.)
Runion, G. Brett; Prior, Stephen A.; Price, Andrew J.; McElroy, J. Scott; Torbert, H. Allen
Herbicide resistant weed populations have developed due to the repeated application of herbicides. Elevated concentrations of atmospheric CO2 can have positive effects on weed growth, but how rising CO2 might affect herbicide resistant weeds is not known. Ragweed (Ambrosia artemisiifolia L.) ecotypes known to be resistant or susceptible to glyphosate herbicide were exposed to either ambient or elevated (ambient +200 ? mol mol?1) concentrations of CO2 in open top chambers. Plants were harvested following 8 weeks of CO2 exposure; at this time, they had begun to exhibit disease symptoms including spots on leaves and stems. Elevated CO2 significantly increased top, root, and total plant biomass. Also, glyphosate resistant plants had significantly greater top, root, and total biomass than plants susceptible to the herbicide. There were no significant CO2 by ecotype interactions. Fungi from 13 genera were associated with ragweed, several of which can be either pathogens (i.e., Alternaria, Fusarium, Rhizoctonia), aiding the decline in health of the ragweed plants, or saprophytes existing on dead plant tissues. The common foliar disease powdery mildew was significantly higher on susceptible compared with resistant ragweed. Susceptible plants also showed an increased frequency of Rhizoctonia on leaves and Alternaria on stems; however, Fusarium occurred more frequently on resistant ragweed leaves. Fungi were not affected by CO2 concentration or its interaction with ecotype. This study reports the first information on the effects of elevated CO2 on growth of herbicide resistant weeds. This is also the first study examining the impact of herbicide resistance and elevated CO2 on fungi associated with weeds. What effects herbicide resistance might have on plant diseases and how rising atmospheric CO2 might impact these effects needs to be addressed, not only with important weeds but also with crops. PMID:25309569
Efficacy of microorganisms selected from compost to control soil-borne pathogens.
Pugliese, M; Gullino, M L; Garibaldi, A
Suppression of soil-borne plant pathogens with compost has been widely studied. Compost has been found to be suppressive against several soil-borne pathogens in various cropping systems. However, an increase of some diseases due to compost usage has also been observed, since compost is a product that varies considerably in chemical, physical and biotic composition, and, consequently, also in ability to suppress soil borne diseases. New opportunities in disease management can be obtained by the selection of antagonists from suppressive composts. The objective of the present work was to isolate microorganisms from a suppressive compost and to test them for their activity against soil-borne pathogens. A compost from green wastes, organic domestic wastes and urban sludge's that showed a good suppressive activity in previous trials was used as source of microorganisms. Serial diluted suspensions of compost samples were plated on five different media: selective for Fusarium sp., selective for Trichoderma sp., selective for oomycetes, potato dextrose agar (PDA) for isolation of fungi, lysogeny broth (LB) for isolation of bacteria. In total, 101 colonies were isolated from plates and tested under laboratory conditions on tomato seedlings growing on perlite medium in Petri plates infected with Fusarium oxysporum f.sp. radicis-lycopersici and compared to a commercial antagonist (Streptomyces griserovidis, Mycostop, Bioplanet). Among them, 28 showed a significant disease reduction and were assessed under greenhouse condition on three pathosystems: Fusarium oxysporum f.sp. basilica/basil, Phytophthora nicotianae/tomato and Rhizoctonia solani/bean. Fusarium spp. selected from compost generally showed a good disease control against Fusarium wilts, while only bacteria significantly controlled P. nicotianae on tomato under greenhouse conditions. None of the microorganisms was able to control the three soil-borne pathogens together, in particular Rhizoctonia solani. Results confirmed the good suppressive activity of the compost under study against soil-borne pathogens. The selection of antagonists from compost is a promising strategy for the development of new biological control agents against soil-borne pathogens. PMID:21534476
Characterization of an antibiotic produced by a strain of Pseudomonas fluorescens inhibitory to Gaeumannomyces graminis var. tritici and Pythium spp.
Gurusiddaiah, S; Weller, D M; Sarkar, A; Cook, R J
The production, isolation, and characterization of an antibiotic substance from cultures of Pseudomonas fluorescens 2-79 (NRRL B-15132) is described. P. fluorescens 2-79 originally was isolated from the roots of wheat and is suppressive to the wheat root disease take-all caused by Gaeumannomyces graminis var. tritici. The antibiotic was isolated from potato glucose broth cultures of strain 2-79 by solvent extraction. It was purified by silica gel column chromatography and was a greenish yellow, needle-shaped crystal with a melting point of 242 degrees C (decomposition). It was soluble in methylene chloride, chloroform, acetone, 2 N sodium hydroxide, and 2 N hydrochloric acid and was insoluble in water, methanol, ethyl acetate, tetrahydrofuran, diethyl ether, carbon tetrachloride, hexane, and petroleum ether. On the basis of UV, infrared, 1H-nuclear magnetic resonance, 13C-nuclear magnetic resonance, mass spectral analysis, and elemental analysis, the structure of the antibiotic is proposed to be a dimer of phenazine carboxylic acid. Lithium aluminum hydride reduction of the antibiotic yielded hydroxymethyl phenazine as a major product which retained most of the biological characteristics of the parent molecule. There were no toxic symptoms when mice received this antibiotic by oral doses up to 464 mg/kg. The antibiotic showed excellent activity against several species of fungi, including the wheat pathogens Gaeumannomyces graminis var. tritici, Rhizoctonia solani, and Pythium aristosporum; and it may have a role in suppression of take-all in vivo by strain 2-79. PMID:3087284
Production of lipopeptides by Bacillus amyloliquefaciens XZ-173 in solid state fermentation using soybean flour and rice straw as the substrate.
Zhu, Zhen; Zhang, Guoyi; Luo, Yi; Ran, Wei; Shen, Qirong
This work was aimed to produce lipopeptides by Bacillus amyloliquefaciens XZ-173 in solid state fermentation using agro-industrial byproducts. A central composite design was used to get the highest lipopeptides production. Results revealed that the optimal conditions for maximum lipopeptides production were 1.79% starch and 1.91% yeast extract by employing 5.58 g soybean flour and 3.67 g rice straw as the solid substrate with initial pH 7.5, moisture content 55% and a 10% inoculum level at 30°C for 2 days. Under these conditions, the experimental yield of lipopeptides reached 50.01 mg/gds, which was very close to the predicted value (49.91 mg/gds). At high concentration, the lipopeptides extracted from fermented substrates showed strong antibiotic activity against Rhizoctonia solani and Ralstonia solanacearum and certain emulsification but good emulsion stability. This is the first report on lipopeptides production that uses rice straw as a major substrate. PMID:22418084
A novel activator-type ERF of Thinopyrum intermedium, TiERF1, positively regulates defence responses
Liang, HongXia; Lu, Yan; Liu, HongXia; Wang, FengDe; Xin, ZhiYong; Zhang, ZengYan
Thinopyrum intermedium is resistant to many different pathogens. To understand the roles of ethylene response factors (ERFs) in defence responses, the first member of the ERF family in T. intermedium, TiERF1, was characterized and functionally analysed in this study. The TiERF1 gene encodes a putative protein of 292 amino acids, belonging to the B3 subgroup of the ERF transcription factor family. Biochemical assays demonstrated that the TiERF1 protein is capable of binding to the GCC box, a cis-element present in the promoters of pathogenesis-related (PR) genes, and possessing transactivation activity, as well as localizing to the nucleus. The transcript of TiERF1 in T. intermedium is rapidly induced by infection with Rhizoctonia cerealis, Fusarium graminearum, or Blumeria graminis, and ethylene, jasmonic acid, and salicylic acid treatments. More importantly, the ectopic expression of TiERF1 in tobacco activated the transcript of the PR genes of tobacco with a GCC box cis-element, and ACO and ACS genes key to ethylene synthesis, and in turn improved the resistance level to Alternaria alternata and tobacco mosaic virus, as well as causing some phenotypic changes associated with ethylene response in the transgenic tobacco plants. Taken together, TiERF1 protein as an ERF transcription activator positively regulates defence responses via the activation of some defence-related genes. PMID:18611911
Resistance to multiple tuber diseases expressed in somaclonal variants of the potato cultivar Russet Burbank.
Thangavel, Tamilarasan; Steven Tegg, Robert; Wilson, Calum Rae
Multiple disease resistance is an aim of many plant breeding programs. Previously, novel somatic cell selection was used to generate potato variants of "Russet Burbank" with resistance to common scab caused by infection with an actinomycete pathogen. Coexpression of resistance to powdery scab caused by a protozoan pathogen was subsequently shown. This study sought to define whether this resistance was effective against additional potato tuber diseases, black scurf, and tuber soft rot induced by fungal and bacterial pathogens. Pot trials and in vitro assays with multiple pathogenic strains identified significant resistance to both tuber diseases across the potato variants examined; the best clone A380 showed 51% and 65% reductions in disease severity to tuber soft rot and black scurf, respectively, when compared with the parent line. The resistance appeared to be tuber specific as no enhanced resistance was recorded in stolons or stem material when challenged Rhizoctonia solani that induces stolon pruning and stem canker. The work presented here suggests that morphological characteristics associated with tuber resistance may be the predominant change that has resulted from the somaclonal cell selection process, potentially underpinning the demonstrated broad spectrum of resistance to tuber invading pathogens. PMID:24523639
The Role of Antioxidant Enzymes in Adaptive Responses to Sheath Blight Infestation under Different Fertilization Rates and Hill Densities
Wan, Xuejie; Shah, Farooq; Fahad, Shah; Huang, Jianliang
Sheath blight of rice, caused by Rhizoctonia solani, is one of the most devastating rice diseases worldwide. No rice cultivar has been found to be completely resistant to this fungus. Identifying antioxidant enzymes activities (activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)) and malondialdehyde content (MDA) responding to sheath blight infestation is imperative to understand the defensive mechanism systems of rice. In the present study, two inoculation methods (toothpick and agar block method) were tested in double-season rice. Toothpick method had greater lesion length than agar block method in late season. A higher MDA content was found under toothpick method compared with agar block method, which led to greater POD and SOD activities. Dense planting caused higher lesion length resulting in a higher MDA content, which also subsequently stimulated higher POD and SOD activity. Sheath blight severity was significantly related to the activity of antioxidant enzyme during both seasons. The present study implies that rice plants possess a system of antioxidant protective enzymes which helps them in adaptation to sheath blight infection stresses. Several agronomic practices, such as rational use of fertilizers and optimum planting density, involved in regulating antioxidant protective enzyme systems can be regarded as promising strategy to suppress the sheath blight development. PMID:25136671
Molecular, biochemical and structural characterization of osmotin-like protein from black nightshade (Solanum nigrum).
Jami, Sravan Kumar; Swathi Anuradha, T; Guruprasad, Lalitha; Kirti, Pulugurtha Bharadwaja
A full-length 910bp cDNA encoding osmotin-like protein with an open reading frame of 744bp encoding a protein of 247 amino acids with a calculated molecular mass of 26.8kDa was cloned from Solanum nigrum (SniOLP). Phylogenetic analysis revealed the evolutionary conservation of this protein among diverse taxa. The genomic DNA gel blot showed that SniOLP belongs to a small multigene family and it showed organ-specific expression. Time-course studies revealed that the expression of SniOLP was upregulated by treatment with various signaling molecules, osmotic and oxidative stress inducers. Recombinant protein purified from overexpressed Escherichia coli cells showed hyphal growth inhibition in Rhizoctonia batiticola and Sclerotinia sclerotiorum but without any endo-beta-1,3-glucanase activity. Model built by homology modeling showed that the protein consists of an acidic cleft region that is capable of interacting with the carbohydrate components of the fungal cell walls. Analysis of the structure and functional relationship was carried out by docking of the beta-(1,3)-glucan onto the acidic cleft region on the surface of the protein (SniOLP). PMID:16542753
Antiproliferative, Antibacterial and Antifungal Activity of the Lichen Xanthoria parietina and Its Secondary Metabolite Parietin
Basile, Adriana; Rigano, Daniela; Loppi, Stefano; Di Santi, Annalisa; Nebbioso, Angela; Sorbo, Sergio; Conte, Barbara; Paoli, Luca; De Ruberto, Francesca; Molinari, Anna Maria; Altucci, Lucia; Bontempo, Paola
Lichens are valuable natural resources used for centuries throughout the world as medicine, food, fodder, perfume, spices and dyes, as well as for other miscellaneous purposes. This study investigates the antiproliferative, antibacterial and antifungal activity of the acetone extract of the lichen Xanthoria parietina (Linnaeus) Theodor Fries and its major secondary metabolite, parietin. The extract and parietin were tested for antimicrobial activity against nine American Type Culture Collection standard and clinically isolated bacterial strains, and three fungal strains. Both showed strong antibacterial activity against all bacterial strains and matched clinical isolates, particularly against Staphylococcus aureus from standard and clinical sources. Among the fungi tested, Rhizoctonia solani was the most sensitive. The antiproliferative effects of the extract and parietin were also investigated in human breast cancer cells. The extract inhibited proliferation and induced apoptosis, both effects being accompanied by modulation of expression of cell cycle regulating genes such as p16, p27, cyclin D1 and cyclin A. It also mediated apoptosis by activating extrinsic and intrinsic cell death pathways, modulating Tumor Necrosis Factor-related apoptosis-inducing ligand (TRAIL) and B-cell lymphoma 2 (Bcl-2), and inducing Bcl-2-associated agonist of cell death (BAD) phosphorylation. Our results indicate that Xanthoria parietina is a major potential source of antimicrobial and anticancer substances. PMID:25860944
Characteristics and antimicrobial activity of Bacillus subtilis strains isolated from soil.
Todorova, Sevdalina; Kozhuharova, Lubka
Antagonistic Bacillus strains were isolated from soil and analyzed for the purpose of determining whether they could be used as natural biological agents. Primary in vitro screening for antagonism of the isolates was performed against five phytopathogenic mould fungi. Strains TS 01 and ZR 02 exhibited the most pronounced inhibitory effects. They were identified as Bacillus subtilis on the basis of their morphological, cultural and physiology-biochemical properties as well as their hierarchical cluster analysis conducted by means of computer program SPSS. The antimicrobial activity of the strains from cultural medium and sterile filtrate were determined in vitro against a great number of predominantly phytopathogenic fungi and bacteria. TS 01 and ZR 02 strains exhibited very broad and at the same time degree varying antibiotic spectra of activities against both Gram-positive and Gram-negative microorganisms. Many of them were tested against sensitivity to the antimicrobial action of B. subtilis for the very first time. B. subtilis TS 01 and ZR 02 showed highest antifungal activity (sterile zone in diameter over 37 mm) against Alternaria solani, Botrytis cinerea, Monilia linhartiana 869, Phytophthora cryptogea 759/1 and Rhizoctonia sp. The most sensitive bacterial species were found to be Pseudomonas syringae pv. tomato Ro and Xanthomonas campestris with sterile zones 48.0 and 50.0 mm in diameter, respectively. The latter draws a conclusion that the isolated and identified Bacillus subtilis strains are promising natural biocontrol agents and should be further studied and tested for control of numerous plant diseases. PMID:24026925
Marine isolates of Trichoderma spp. as potential halotolerant agents of biological control for arid-zone agriculture.
Gal-Hemed, Inbal; Atanasova, Lea; Komon-Zelazowska, Monika; Druzhinina, Irina S; Viterbo, Ada; Yarden, Oded
The scarcity of fresh water in the Mediterranean region necessitates the search for halotolerant agents of biological control of plant diseases that can be applied in arid-zone agriculture irrigated with saline water. Among 29 Trichoderma strains previously isolated from Mediterranean Psammocinia sp. sponges, the greatest number of isolates belong to the Trichoderma longibrachiatum-Hypocrea orientalis species pair (9), H. atroviridis/T. atroviride (9), and T. harzianum species complex (7), all of which are known for high mycoparasitic potential. In addition, one isolate of T. asperelloides and two putative new species, Trichoderma sp. O.Y. 14707 and O.Y. 2407, from Longibrachiatum and Strictipilosa clades, respectively, have been identified. In vitro salinity assays showed that the ability to tolerate increasing osmotic pressure (halotolerance) is a strain- or clade-specific property rather than a feature of a species. Only a few isolates were found to be sensitive to increased salinity, while others either were halotolerant or even demonstrated improved growth in increasingly saline conditions. In vitro antibiosis assays revealed strong antagonistic activity toward phytopathogens due to the production of both soluble and volatile metabolites. Two marine-derived Trichoderma isolates, identified as T. atroviride and T. asperelloides, respectively, effectively reduced Rhizoctonia solani damping-off disease on beans and also induced defense responses in cucumber seedlings against Pseudomonas syringae pv. lachrimans. This is the first inclusive evaluation of marine fungi as potential biocontrol agents. PMID:21666030
Thiamine primed defense provides reliable alternative to systemic fungicide carbendazim against sheath blight disease in rice (Oryza sativa L.).
Bahuguna, Rajeev Nayan; Joshi, Rohit; Shukla, Alok; Pandey, Mayank; Kumar, J
A novel pathogen defense strategy by thiamine priming was evaluated for its efficacy against sheath blight pathogen, Rhizoctonia solani AG-1A, of rice and compared with that of systemic fungicide, carbendazim (BCM). Seeds of semidwarf, high yielding, basmati rice variety Vasumati were treated with thiamine (50 mM) and BCM (4 mM). The pot cultured plants were challenge inoculated with R. solani after 40 days of sowing and effect of thiamine and BCM on rice growth and yield traits was examined. Higher hydrogen peroxide content, total phenolics accumulation, phenylalanine ammonia lyase (PAL) activity and superoxide dismutase (SOD) activity under thiamine treatment displayed elevated level of systemic resistance, which was further augmented under challenging pathogen infection. High transcript level of phenylalanine ammonia lyase (PAL) and manganese superoxide dismutase (MnSOD) validated mode of thiamine primed defense. Though minimum disease severity was observed under BCM treatment, thiamine produced comparable results, with 18.12 per cent lower efficacy. Along with fortifying defense components and minor influence on photosynthetic pigments and nitrate reductase (NR) activity, thiamine treatment significantly reduced pathogen-induced loss in photosynthesis, stomatal conductance, chlorophyll fluorescence, NR activity and NR transcript level. Physiological traits affected under pathogen infection were found signatory for characterizing plant's response under disease and were detectable at early stage of infection. These findings provide a novel paradigm for developing alternative, environmentally safe strategies to control plant diseases. PMID:22705591
Expression of a plant defensin in rice confers resistance to fungal phytopathogens.
Jha, Sanjay; Chattoo, Bharat B
Transgenic rice (Oryza sativa L. cv. Pusa basmati 1), overexpressing the Rs-AFP2 defensin gene from the Raphanus sativus was generated by Agrobacterium tumefaciens-mediated transformation. Expression levels of Rs-AFP2 ranged from 0.45 to 0.53% of total soluble protein in transgenic plants. It was observed that constitutive expression of Rs-AFP2 suppresses the growth of Magnaporthe oryzae and Rhizoctonia solani by 77 and 45%, respectively. No effect on plant morphology was observed in the Rs-AFP2 expressing rice lines. The inhibitory activity of protein extracts prepared from leaves of Rs-AFP2 plants on the in vitro growth of M. oryzae indicated that the Rs-AFP2 protein produced by transgenic rice plants was biologically active. Transgene expression of Rs-AFP2 was not accompanied by an induction of pathogenesis-related (PR) gene expression, suggesting that the expression of Rs-AFP2 directly inhibits the pathogens. Here, we demonstrate that transgenic rice plants expressing the Rs-AFP2 gene show enhanced resistance to M. oryzae and R. solani, two of the most important pathogens of rice. PMID:19690975
Two compounds from allelopathic rice accession and their inhibitory activity on weeds and fungal pathogens.
Kong, Chuihua; Xu, Xiaohua; Zhou, Bin; Hu, Fei; Zhang, Chaoxian; Zhang, Maoxin
A flavone (5,7,4'-trihydroxy-3',5'-dimethoxyflavone), a cyclohexenone (3-isopropyl-5-acetoxycyclohexene-2-one-1) and a liquid mixture of low polarity, containing long-chain and cyclic hydrocarbons, were isolated from leaves of allelopathic rice accession PI 312777 using column chromatography. Their structures and constituents were identified by means of HR-MS, NMR and GC/MS analyses, respectively. Bioassays showed that both the flavone and cyclohexenone significantly inhibited the growth of weeds Echinochloa crus-galli, Cyperus difformis and Cyperus iris, and the spore germination of fungal pathogens Pyricularia oryzae and Rhizoctonia solani at all tested concentrations. Moreover, the combination of the inactive mixture of low polarity and the active flavone or cyclohexenone significantly enhanced the inhibitory activities on weed growth. In addition, the two compounds and the mixture of low polarity from the leaves of PI312777 did not inhibit the rice growth at the same concentrations. It was also established that both compounds could be released into the soil, and was especially induced by E. crus-galli. The results suggest that 5,7,4'-trihydroxy-3',5'-dimethoxyflavone and 3-isopropyl- 5-acetoxycyclohexene-2-one-1 may act as allelochemicals participating in the defense of rice against weeds and pathogens. PMID:15110693
Homotypic clustering of OsMYB4 binding site motifs in promoters of the rice genome and cellular-level implications on sheath blight disease resistance.
Pooja, Singh; Sweta, Kumari; Mohanapriya, A; Sudandiradoss, C; Siva, Ramamoorthy; Gothandam, Kodiveri M; Babu, Subramanian
The promoter regions (1 kb upstream sequences) of 45,836 annotated genes of rice were analyzed for the presence of OsMYB4 binding sites using a Perl program algorithm. Based on the homotypic clustering concept, 113 promoters were found to have more than 4 binding site motifs. Among the downstream genes of these promoters, five genes which are known to have a role in disease resistance were selected and the binding capacity of OsMYB4 protein in the promoter regions was analyzed by docking studies. Expression level of these genes was analyzed by RT-PCR in Rhizoctonia solani infected rice seedlings. Upon pathogen challenge, higher expression of aminotransferase, ankyrin and WRKY 12 genes was observed corresponding to higher expression of Osmyb4. Over-expression of Osmyb4 cDNA in rice leaf tissues by agro-infection failed to result in similar over-expression of aminotransferase, ankyrin and WRKY 12 as expected. Although the role of OsMYB4 in sheath blight resistance was found to be definitive based on our initial results, artificial over-expression of this TF was observed to be insufficient in regulating the disease resistance related genes. PMID:25688880
Four genes from Pseudomonas fluorescens that encode the biosynthesis of pyrrolnitrin.
Hammer, P E; Hill, D S; Lam, S T; Van Pée, K H; Ligon, J M
Pyrrolnitrin is a secondary metabolite of Pseudomonas and Burkholderia sp. strains with strong antifungal activity. Production of pyrrolnitrin has been correlated with the ability of some bacteria to control plant diseases caused by fungal pathogens, including the damping-off pathogen Rhizoctonia solani. Pseudomonas fluorescens BL915 has been reported to produce pyrrolnitrin and to be an effective biocontrol agent for this pathogen. We have isolated a 32-kb genomic DNA fragment from this strain that contains genes involved in the biosynthesis of pyrrolnitrin. Marker-exchange mutagenesis of this DNA with Tn5 revealed the presence of a 6.2-kb region that contains genes required for the synthesis of pyrrolnitrin. The nucleotide sequence of the 6.2-kb region was determined and found to contain a cluster of four genes that are required for the production of pyrrolnitrin. Deletion mutations in any of the four genes resulted in a pyrrolnitrin-nonproducing phenotype. The putative coding sequences of the four individual genes were cloned by PCR and fused to the tac promoter from Escherichia coli. In each case, the appropriate tac promoter-pyrrolnitrin gene fusion was shown to complement the pyrrolnitrin-negative phenotype of the corresponding deletion mutant. Transfer of the four gene cluster to E. coli resulted in the production of pyrrolnitrin by this organism, thereby demonstrating that the four genes are sufficient for the production of this metabolite and represent all of the genes required to encode the pathway for pyrrolnitrin biosynthesis. PMID:9172332
Evaluation of the potential of Trichoderma viride in the control of fungal pathogens of Roselle (Hibiscus sabdariffa L.) in vitro.
Eslaminejad Parizi, T; Ansaria, Mehdi; Elaminejad, Tahereh
The potential of Trichoderma viride as a bio-control agent was evaluated in vitro against Roselle pathogens i.e. Phoma exigua, Fusarium nygamai and Rhizoctonia solani[1] using the dual culture technique. Volatile and non-volatile inhibitors of Trichoderma were also evaluated for this purpose. T. viride[2] was shown to have a marked inhibitory effect on the tested pathogens in vitro. Maximum inhibition occurred against P. exigua, with 71.76% reduction in mycelial radial growth. The three pathogens, P. exigua, F. nygamai and R. solani were also found to be susceptible to the volatile inhibitors produced by T. viride, giving rise to growth inhibition of about 68% in each case. When T. viride non-volatile metabolites were tested against the pathogens, maximum inhibition occurred against R. solani (73.95% mycelial growth inhibition), followed by P. exigua (37.17% inhibition). The inhibitory effect of the non-volatile metabolites on F. nygamai was, however, minimal. PMID:22261114
Anti-fungal activity of cold and hot water extracts of spices against fungal pathogens of Roselle (Hibiscus sabdariffa) in vitro.
Touba, Eslaminejad Parizi; Zakaria, Maziah; Tahereh, Eslaminejad
Crude extracts of seven spices, viz. cardamom, chilli, coriander, onion, garlic, ginger, and galangale were made using cold water and hot water extraction and they were tested for their anti-fungal effects against the three Roselle pathogens i.e. Phoma exigua, Fusarium nygamai and Rhizoctonia solani using the 'poisoned food technique'. All seven spices studied showed significant anti-fungal activity at three concentrations (10, 20 and 30% of the crude extract) in-vitro. The cold water extract of garlic exhibited good anti-fungal activity against all three tested fungi. In the case of the hot water extracts, garlic and ginger showed the best anti-fungal activity. Of the two extraction methods, cold water extraction was generally more effective than hot water extraction in controlling the pathogens. Against P. exigua, the 10% cold water extracts of galangale, ginger, coriander and cardamom achieved total (100%) inhibition of pathogen mycelial growth. Total inhibition of F. nygamai mycelial growth was similarly achieved with the 10% cold water extracts garlic. Against R. solani, the 10% cold water extract of galangale was effective in imposing 100% inhibition. Accordingly, the 10% galangale extract effectively controlled both P. exigua and R. solani in vitro. None of the hot water extracts of the spices succeeded in achieving 100% inhibition of the pathogen mycelial growth. PMID:22138549
Dioxygen reactivity of laccase: dependence on laccase source, pH, and anion inhibition.
Xu, F
A study was carried out on the dioxygen reactivity of the laccases from Trametes villosa, Rhizoctonia solani, Myceliophthora thermophila, Scytalidium thermophilum, and Coprinus cinereus. At pH 5.5, these laccases showed an apparently constant Km (about 20-50 microM) for O2 with either 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) or methyl syringate as the reducing substrate, in contrast to the kcat, which varied up to 100-fold. O2 reactivity of the Trametes and Myceliophthora laccases was also studied at various pH and NaF concentrations. The apparent Km of Trametes and Myceliophthora laccases varied only slightly when pH changed from 3.0 to 8.0 or when the laccases were inhibited by F- at pH 5.5, although the apparent kcat were more significantly affected by both factors. The dependence of the apparent Km on the source of laccase, pH, and F- inhibition suggested that the fungal laccases might have a conserved O2 pocket and that the F- or OH- inhibition might affect the O2 reduction step (kcat) more than the O2 binding step (Km) under steady-state conditions. PMID:11694062
Characterization of the volatile constituents in the essential oil of Pistacia lentiscus L. from different origins and its antifungal and antioxidant activity.
Barra, Andrea; Coroneo, Valentina; Dessi, Sandro; Cabras, Paolo; Angioni, Alberto
Essential oil (EO) from aerial parts (leaves, juvenile branches, and flowers when present) of Pistacia lentiscus L. growing wild in five localities of Sardinia (Italy) was extracted by steam-distillation (SD) and analyzed by gas chromatography (GC), FID, and GC-ion trap mass spectrometry (ITMS). Samples of P. lentiscus L. were harvested between April and October to study the seasonal chemical variability of the EO. A total of 45 compounds accounting for 97.5-98.4% of the total EO were identified, and the major compounds were alpha-pinene (14.8-22.6%), beta-myrcene (1-19.4%), p-cymene (1.6-16.2%), and terpinen-4-ol (14.2-28.3%). The yields of EO (v/dry w) ranged between 0.09 and 0.32%. Similar content of the major compounds was found in samples from different origins and seasonal variability was also observed. The EOs were tested for their antifungal activity against Aspergillus flavus, Rhizoctonia solani, Penicillium commune, Fusarium oxysporum. Two samples were weakly effective against Aspergillus flavus. Furthermore, terpinenol and alpha-terpineol, two of the major components of EO of Pistacia lentiscus L., totally inhibited the mycelian growth of A. flavus. Quite good antioxidant activity of the EO was also found. PMID:17658828
Chemical composition, seasonal variability, and antifungal activity of Lavandula stoechas L. ssp. stoechas essential oils from stem/leaves and flowers.
Angioni, Alberto; Barra, Andrea; Coroneo, Valentina; Dessi, Sandro; Cabras, Paolo
Essential oils from the stems/leaves (L) and flowers (F) of Lavandula stoechas L. ssp. stoechas growing wild in southern Sardinia (Italy) were extracted by hydrodistillation and analyzed by gas chromatography coupled with flame ionization detector and ion trap mass spectrometry. The major compound was fenchone, accounting for, on average, 52.60% in L and 66.20% in F, followed by camphor (13.13% versus 27.08%, in L and F, respectively). F essential oil yields (volume per dry weight) decreased from the beginning to the end of the flowering stage, whereas L yields remained constant during the year. The nine main compounds derived from two different subpathways, A and B. The compounds that belong to the same subpathway showed a similar behavior during the year. The essential oils were tested for their antifungal activity using the paper disk diffusion method. The essential oils tested were effective on the inactivation of Rhizoctonia solani and Fusarium oxysporum and less effective against Aspergillus flavus. Among the single compounds tested, fenchone, limonene, and myrtenal appeared to be the more effective on the inhibition of R. solani growth. PMID:16756368
Composition and antipathogenic activities of the twig essential oil of Chamaecyparis formosensis from Taiwan.
Ho, Chen-Lung; Hua, Kuo-Feng; Hsu, Kuan-Ping; Wang, Eugene I-chen; Su, Yu-Chang
In this study, antipathogenic activities of the twig essential oil and its constituents from Chamaecyparis formosensis Matsum were evaluated in vitro against six plant pathogenic fungi. The essential oil from the fresh twigs was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. Twenty-five compounds were identified, representing 98.9% of the oil. The main components were beta-eudesmol (25.1%), tau-muurolol (21.6%), elemol (15.0%), totarol (14.9%), and alpha-cadinol (12.4%). The twig oil (500 mcirog/mL) showed growth inhibitory activity against the phytopathogenic fungi, Fusarium oxysporum, Pestalotiopsis funereal, and Ganoderma austral, with antifungal indices of 92.7%, 71.1%, and 87.7%, respectively. In addition, the oil suppressed totally the growth of Rhizoctonia solani, Colletotrichum gloeosporioides, and Fusarium solani. In order to ascertain the source compounds of these antipathogenic activities, the main components were individually evaluated. Tau-Muurolol and alpha-cadinol exhibited excellent activity against F. oxysporum, R. solani, C. gloeosporioides, and F. solani, with IC50 < 50 microg/mL. These compounds also efficiently inhibited the mycelial growths of P. funereal and G. austral. Thus, alpha-cadinol and tau-muurolol could be considered as potential natural fungicides for controlling fungal pathogens and worth. PMID:22908586
Implementation of bio-fungicides and seed treatment in organic rice cv. KDML 105 farming.
Thobunluepop, Pitipong
This study was aimed to evaluate the several chemical compounds of relatively composite structure with antifungal activity from Thai local medical plants. The antifungal activity of Stemona curtisii HK. f., Stemona tuberose L., Acorus calamus L., Eugenia caryophyllus, Memmea siamensis Kost. and an eugenol active compound were studied in vitro. Four pathogenic seed borne fungi, Alternaria solani, Colletotrichum sp., Fusarium moniliforme and Rhizoctonia solani were used as target organisms. The agar overlay technique and spore inhibition techniques were applied for the determination of their essential oil and active compound antifungal activity at various concentration; 0.10, 0.25, 0.50 and 1.00% (v/v) and untreated as control (0% v/v). Eugenol active compound showed the strongest antifungal activity on all species of tested fungal species. On the other hand, the antifungal activity of those bio-fungicides was lined up into a series from strong to low, as follows: Eugenia caryophyllus > Acorus calamus Linn. > Stemona tuberosa L. > Stemona curtisii Hk.f, while Mammea siamensis Kost. could not control any fungal species. Moreover, after eugenol application, lysis of spore and inhibition of mycelium growth were detected. Microscopic analysis exhibited complete lysis of spores after 24 h at a concentration of 1.00% v/v. Moreover, at the same concentration and 96 h incubation the mycelia growth was completely inhibited. PMID:19899322
Identification of Mycoparasitism-Related Genes in Trichoderma atroviride ? † ‡
Reithner, Barbara; Ibarra-Laclette, Enrique; Mach, Robert L.; Herrera-Estrella, Alfredo
A high-throughput sequencing approach was utilized to carry out a comparative transcriptome analysis of Trichoderma atroviride IMI206040 during mycoparasitic interactions with the plant-pathogenic fungus Rhizoctonia solani. In this study, transcript fragments of 7,797 Trichoderma genes were sequenced, 175 of which were host responsive. According to the functional annotation of these genes by KOG (eukaryotic orthologous groups), the most abundant group during direct contact was "metabolism." Quantitative reverse transcription (RT)-PCR confirmed the differential transcription of 13 genes (including swo1, encoding an expansin-like protein; axe1, coding for an acetyl xylan esterase; and homologs of genes encoding the aspartyl protease papA and a trypsin-like protease, pra1) in the presence of R. solani. An additional relative gene expression analysis of these genes, conducted at different stages of mycoparasitism against Botrytis cinerea and Phytophthora capsici, revealed a synergistic transcription of various genes involved in cell wall degradation. The similarities in expression patterns and the occurrence of regulatory binding sites in the corresponding promoter regions suggest a possible analog regulation of these genes during the mycoparasitism of T. atroviride. Furthermore, a chitin- and distance-dependent induction of pra1 was demonstrated. PMID:21531825
Nonribosomal Peptides, Key Biocontrol Components for Pseudomonas fluorescens In5, Isolated from a Greenlandic Suppressive Soil
Michelsen, Charlotte F.; Watrous, Jeramie; Glaring, Mikkel A.; Kersten, Roland; Koyama, Nobuhiro
ABSTRACT Potatoes are cultivated in southwest Greenland without the use of pesticides and with limited crop rotation. Despite the fact that plant-pathogenic fungi are present, no severe-disease outbreaks have yet been observed. In this report, we document that a potato soil at Inneruulalik in southern Greenland is suppressive against Rhizoctonia solani Ag3 and uncover the suppressive antifungal mechanism of a highly potent biocontrol bacterium, Pseudomonas fluorescens In5, isolated from the suppressive potato soil. A combination of molecular genetics, genomics, and matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) imaging mass spectrometry (IMS) revealed an antifungal genomic island in P. fluorescens In5 encoding two nonribosomal peptides, nunamycin and nunapeptin, which are key components for the biocontrol activity by strain In5 in vitro and in soil microcosm experiments. Furthermore, complex microbial behaviors were highlighted. Whereas nunamycin was demonstrated to inhibit the mycelial growth of R. solani Ag3, but not that of Pythium aphanidermatum, nunapeptin instead inhibited P. aphanidermatum but not R. solani Ag3. Moreover, the synthesis of nunamycin by P. fluorescens In5 was inhibited in the presence of P. aphanidermatum. Further characterization of the two peptides revealed nunamycin to be a monochlorinated 9-amino-acid cyclic lipopeptide with similarity to members of the syringomycin group, whereas nunapeptin was a 22-amino-acid cyclic lipopeptide with similarity to corpeptin and syringopeptin. PMID:25784695
Antiproliferative, antibacterial and antifungal activity of the lichen Xanthoria parietina and its secondary metabolite parietin.
Basile, Adriana; Rigano, Daniela; Loppi, Stefano; Di Santi, Annalisa; Nebbioso, Angela; Sorbo, Sergio; Conte, Barbara; Paoli, Luca; De Ruberto, Francesca; Molinari, Anna Maria; Altucci, Lucia; Bontempo, Paola
Lichens are valuable natural resources used for centuries throughout the world as medicine, food, fodder, perfume, spices and dyes, as well as for other miscellaneous purposes. This study investigates the antiproliferative, antibacterial and antifungal activity of the acetone extract of the lichen Xanthoria parietina (Linnaeus) Theodor Fries and its major secondary metabolite, parietin. The extract and parietin were tested for antimicrobial activity against nine American Type Culture Collection standard and clinically isolated bacterial strains, and three fungal strains. Both showed strong antibacterial activity against all bacterial strains and matched clinical isolates, particularly against Staphylococcus aureus from standard and clinical sources. Among the fungi tested, Rhizoctonia solani was the most sensitive. The antiproliferative effects of the extract and parietin were also investigated in human breast cancer cells. The extract inhibited proliferation and induced apoptosis, both effects being accompanied by modulation of expression of cell cycle regulating genes such as p16, p27, cyclin D1 and cyclin A. It also mediated apoptosis by activating extrinsic and intrinsic cell death pathways, modulating Tumor Necrosis Factor-related apoptosis-inducing ligand (TRAIL) and B-cell lymphoma 2 (Bcl-2), and inducing Bcl-2-associated agonist of cell death (BAD) phosphorylation. Our results indicate that Xanthoria parietina is a major potential source of antimicrobial and anticancer substances. PMID:25860944
Isolation, purification, and characterization of a stable defensin-like antifungal peptide from Trigonella foenum-graecum (fenugreek) seeds.
Oddepally, R; Guruprasad, L
A novel defensin-like antifungal peptide (Tf-AFP) with molecular mass of 10.3 kDa was isolated from seeds of Trigonella foenum-graecum (fenugreek) by ammonium sulfate precipitation, cation-exchange, gel-filtration, hydrophobic chromatography, and RP-HPLC. Mass spectroscopic analysis revealed the intact mass of the purified antifungal peptide as 10321.5 Da and high similarity to plant defensins and other antifungal proteins in database search. 2D-PAGE showed pI value to be 8.8 and absence of isoforms. Isolated Tf-AFP inhibited growth of fungal species such as Fusarium oxysporum, Fusarium solani, and Rhizoctonia solani. The antifungal activity was inhibited in the presence of 50 mM NaCl. Circular dichroism analysis demonstrated that the protein is rich in ?-sheet structure and highly stable over a wide range of temperatures. Surprisingly, reduction of disulfide bridges and chemical denaturation did not produce large changes in secondary structure as judged by circular dichroism as well as by fluorescence spectroscopy. PMID:25761687
Development of pyramidal lines with two major QTLs conferring resistance to sheath blight in rice (Oryza sativa L.)
NASA Astrophysics Data System (ADS)
Hossain, Md Kamal; Jena, Kshirod; Bhuiyan, Md Atiqur Rahman; Ratnam, Wickneswari
Sheath blight is an emerging threat in rice cultivation. It is animportant disease caused by the soil-borne necrotrophic pathogenic fungus, Rhizoctonia solani Kühn. However, to date neither known major genes for quantitative resistance, nor any rice lines immune to this disease has been identified. The disease resistance is quantitative in nature. Numerous genes are involved in this resistance process. There are few quantitative trait loci (QTLs) detected conferring improved resistance against the disease. Teqing and Tetepshowimproved resistance having QTLs, qSB-9 and qSBR11-1, respectively. Since, these QTLs demonstrates additive effects, pyramiding of these QTLs might be an option to increase the sheath blight resistance in rice. Nine rice cultivars were screened at greenhouse conditions. Results showed that Tetep and Teqing had the lowest disease ratings. UKMRC2a new high yielding cultivar was as recipient parent. Crosses between UKMRC2 and Teqing, and UKMRC2 and Tetep were made and confirmed. Subsequently 4-way crosses between the two F1s were performed to develop pyramidal lines.
DNA binding mode of novel tetradentate amino acid based 2-hydroxybenzylidene-4-aminoantipyrine complexes
NASA Astrophysics Data System (ADS)
Raman, N.; Sobha, S.; Selvaganapathy, M.; Mahalakshmi, R.
Few transition metal complexes of tetradentate N2O2 donor Schiff base ligands containing 2-hydroxybenzylidene-4-aminoantipyrine and amino acids (alanine/valine) abbreviated to KHL1/KHL2 have been synthesized. All the metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The Schiff bases KHL1/KHL2 are found to act as tetradentate ligands using N2O2 donor set of atoms leading to a square-planar geometry for the complexes around the metal ions. The binding behaviors of the complexes to calf thymus DNA have been investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The DNA binding constants reveal that all these complexes interact with DNA through minor groove binding mode. The studies on mechanism of photocleavage reveal that singlet oxygen (1O2) and superoxide anion radical (O2rad -) may play an important role in the photocleavage. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Klebsiella pneumoniae and antifungal activities against Aspergillus niger, Fusarium solani, Culvularia lunata, Rhizoctonia bataicola and Candida albicans by MIC method.
Antimicrobial activity of UV-induced phenylamides from rice leaves.
Park, Hye Lin; Yoo, Youngchul; Hahn, Tae-Ryong; Bhoo, Seong Hee; Lee, Sang-Won; Cho, Man-Ho
Rice produces a wide array of phytoalexins in response to pathogen attacks and UV-irradiation. Except for the flavonoid sakuranetin, most phytoalexins identified in rice are diterpenoid compounds. Analysis of phenolic-enriched fractions from UV-treated rice leaves showed that several phenolic compounds in addition to sakuranetin accumulated remarkably in rice leaves. We isolated two compounds from UV-treated rice leaves using silica gel column chromatography and preparative HPLC. The isolated phenolic compounds were identified as phenylamide compounds: N-trans-cinnamoyltryptamine and N-p-coumaroylserotonin. Expression analysis of biosynthetic genes demonstrated that genes for arylamine biosynthesis were upregulated by UV irradiation. This result suggested that phenylamide biosynthetic pathways are activated in rice leaves by UV treatment. To unravel the role of UV-induced phenylamides as phytoalexins, we examined their antimicrobial activity against rice fungal and bacterial pathogens. N-trans-Cinnamoyltryptamine inhibited the growth of rice brown spot fungus (Bipolaris oryzae). In addition to the known antifungal activity to the blast fungus, sakuranetin had antimicrobial activity toward B. oryzae and Rhizoctonia solani (rice sheath blight fungus). UV-induced phenylamides and sakuranetin also had antimicrobial activity against rice bacterial pathogens for grain rot (Burkholderia glumae), blight (Xanthomonas oryzae pv. oryzae) and leaf streak (X. oryzae pv. oryzicola) diseases. These findings suggested that the UV-induced phenylamides in rice are phytoalexins against a diverse array of pathogens. PMID:25383752
Fungal cellulase is an elicitor but its enzymatic activity is not required for its elicitor activity.
Ma, Yanan; Han, Chao; Chen, Jinyin; Li, Haiyun; He, Kun; Liu, Aixin; Li, Duochuan
Plant-pathogenic fungi produce cellulases. However, little information is available on cellulase as an elicitor in plant-pathogen interactions. Here, an endocellulase (EG1) was isolated from Rhizoctonia solani. It contains a putative protein of 227 amino acids with a signal peptide and a family-45 glycosyl hydrolase domain. Its aspartic acid (Asp) residue at position 32 was changed to alanine (Ala), resulting in full loss of its catalytic activity. Wild-type and mutated forms of the endoglucanase were expressed in yeast and purified to homogeneity. The purified wild-type and mutant forms induced cell death in maize, tobacco and Arabidopsis leaves, and the transcription of three defence marker genes in maize and tobacco and 10 genes related to defence responses in maize. Moreover, they also induced the accumulation of reactive oxygen species (ROS), medium alkalinization, Ca(2+) accumulation and ethylene biosynthesis of suspension-cultured tobacco cells. Similarly, production of the EG1 wild-type and mutated forms in tobacco induced cell death using the Potato virus X (PVX) expression system. In?vivo, expression of EG1 was also related to cell death during infection of maize by R.?solani. These results provide direct evidence that the endoglucanase is an elicitor, but its enzymatic activity is not required for its elicitor activity. PMID:24844544
Synthesis and antifungal activity of 5-iodo-1,4-disubstituted-1,2,3-triazole derivatives as pyruvate dehydrogenase complex E1 inhibitors.
He, Jun-Bo; He, Hai-Feng; Zhao, Lu-Lu; Zhang, Li; You, Ge-Yun; Feng, Ling-Ling; Wan, Jian; He, Hong-Wu
To identify new antifungal lead compound based on inhibitors of pyruvate dehydrogenase complex E1, a series of 5-iodo-1,4-disubstituted-1,2,3-triazole derivatives 3 were prepared and evaluated for their Escherichia coli PDHc-E1 inhibitory activity and antifungal activity. The in vitro bioassay for the PDHc-E1 inhibition indicated all the compounds exhibited significant inhibition against E. coli PDHc-E1 (IC50<21?M), special compound 3g showed the most potent inhibitory activity (IC50=4.21±0.11?M) and was demonstrated to act as a competitive inhibitor of PDHc-E1. Meanwhile, inhibitor 3g exhibited very good enzyme-selective inhibition of PDHc-E1 between pig heart and E. coli. The assay of antifungal activity showed compounds 3e, 3g, and 3n exhibited fair to good activity against Rhizoctonia solani and Botrytis cinerea even at 12.5?g/mL. Especially compound 3n (EC50=5.4?g/mL; EC90=21.1?g/mL) exhibited almost 5.50 times inhibitory potency against B. cinerea than that of pyrimethanil (EC50=29.6?g/mL; EC90=113.4?g/mL). Therefore, in this study, compound 3n was found to be a novel lead compound for further optimization to find more potent antifungal compounds as microbial PDHc-E1 inhibitors. PMID:25766628
Enantioselective bioactivity, acute toxicity and dissipation in vegetables of the chiral triazole fungicide flutriafol.
Zhang, Qing; Hua, Xiu-de; Shi, Hai-yan; Liu, Ji-song; Tian, Ming-ming; Wang, Ming-hua
The enantioselective bioactivity, acute toxicity and stereoselective degradation of the chiral triazole fungicide flutriafol in vegetables were investigated for the first time using the (R)-, (S)- and rac-flutriafol. The order of the bioactivity against five target pathogens (Rhizoctonia solani, Alternaria solani, Pyricularia grisea, Gibberella zeae, Botrytis cinerea) was found to be (R)-flutriafol>rac-flutriafol>(S)-flutriafol. The fungicidal activity of (R)-flutriafol was 1.49-6.23 times higher than that of (S)-flutriafol. The (R)-flutriafol also showed 2.17-3.52 times higher acute toxicity to Eisenia fetida and Scenedesmus obliquus than (S)-flutriafol. The stereoselective degradation of flutriafol in tomato showed that the active (R)-flutriafol degraded faster, resulting in an enrichment of inactive (S)-form, and the half-lives were 9.23 d and 10.18 d, respectively. Inversely, the (S)-flutriafol, with a half-life of 4.76 d, was preferentially degraded in cucumber. In conclusion, the systemic assessments of the triazole fungicide flutriafol stereoisomers on the enantioselective bioactivity, acute toxicity and environmental behavior may have implications for better environmental and ecological risk assessment. PMID:25463219
Transformation of halogen-, alkyl-, and alkoxy-substituted anilines by a lactase of Trametes versicolor
Hoff, T.; Liu, S.Y.; Bollag, J.M.
The lactase of the fungus Trametes versicolor was able to polymerize various halogen-, alkyl-, and alkoxy-substituted anilines, showing substrate specificity similar to that of horseradish peroxidase, whereas the lactase of Rhizoctonia praticola was active only with p-methoxyaniline. The substrate specificities of the enzymes were determined by using gas chromatography to measure the decrease in substrate concentration during incubation. With p-chloroaniline as the substrate, the peroxidase and the Trametes lactase showed maximum activity near pH 4.2. The transformation of this substrate gave rise to a number of oligomers, ranging from dimers to pentamers, as determined by mass spectrometry. The product profiles obtained by high-pressure liquid chromatography were similar for the two enzymes. A chemical reaction was observed between p-chloroaniline and an enzymatically formed dimer, resulting in the formation of a trimer. All three enzymes oxidized p-methoxyaniline to 2-amino-5-p-anisidinobenzoquinone di-p-methoxyphenylimine, but only the T. versicolor lactase and the peroxidase caused the formation of a pentamer (2,5-di-p-anisidinobenzoquinone di-p-methoxyphenylimine). These results demonstrate that in addition to horseradish peroxidase, a T. versicolor lactase can also polymerize aniline derivatives.
The effects of some polyamine biosynthetic inhibitors on growth and morphology of phytopathogenic fungi
NASA Technical Reports Server (NTRS)
Rajam, M. V.; Galston, A. W.
We have studied the effects of two polyamine biosynthetic inhibitors, alpha-difluoromethylornithine (DFMO) and alpha-difluoromethylarginine (DFMA), and of polyamines (PAs), alone and in combination, on mycelial growth and morphology of four phytopathogenic fungi: Botrytis sp, B. cinerea, Rhizoctonia solani and Monilinia fructicola. The inhibitors were added to a Czapek agar medium to get final concentrations of 0.1, 0.5 and 1.0 mM. DFMO and DFMA, suicide inhibitors of ornithine decarboxylase (ODC) and arginine decarboxylase (ADC) respectively, inhibited mycelial growth strongly; the effect was generally more pronounced with DFMA than with DFMO, but each fungus had its own response pattern. The addition of the PAs putrescine (Put) and spermidine (Spd) to the culture medium resulted in a promotion of growth. In Botrytis sp and Monilinia fructicola exposed to inhibitors plus PAs, mycelial growth was actually increased above control values. Mycelial morphology was altered and cell size dramatically reduced in plates containing inhibitors alone, whereas with PAs alone, or in combination with inhibitors, morphology was normal, but cell length and diameters increased considerably. These results suggest that PAs are essential for growth in fungal mycelia. The inhibition caused by DFMA may be due to its arginase-mediated conversion to DFMO.
Pathogen-induced SGT1 of Arachis diogoi induces cell death and enhanced disease resistance in tobacco and peanut.
Kumar, Dilip; Kirti, Pulugurtha Bharadwaja
We have identified a transcript derived fragment (TDF) corresponding to SGT1 in a study of differential gene expression on the resistant wild peanut, Arachis diogoi, upon challenge from the late leaf spot pathogen, Phaeoisariopsis personata, and cloned its full-length cDNA followed by subsequent validation through q-PCR. Sodium nitroprusside, salicylic acid, ethephon and methyl jasmonate induced the expression of AdSGT1, while the treatment with abscisic acid did not elicit its up-regulation. AdSGT1 is localized to both nucleus and cytoplasm. Its overexpression induced hypersensitive-like cell death in tobacco under transient conditional expression using the estradiol system, and this conditional expression of AdSGT1 was also associated with the up-regulation of NtHSR203J, HMGR and HIN1, which have been shown to be associated with hypersensitive response in tobacco in earlier studies. Expression of the cDNA in a susceptible cultivated peanut variety enhanced its resistance against the late leaf spot pathogen, Phaeoisariopsis personata, while the heterologous expression in tobacco enhanced its resistance against Phytophthora parasitica var. nicotianae, Alternaria alternata var. nicotianae and Rhizoctonia solani. Constitutive expression in peanut was associated with the co-expression of resistance-related genes, CC-NB-LRR and some protein kinases. PMID:25236372
Isolation and identification of antagonistic bacteria from phylloplane of rice as biocontrol agents for sheath blight.
Akter, Shamima; Kadir, Jugah; Juraimi, Abdul Shukor; Saud, Halimi Mohd; Elmahdi, Salha
A total of 325 bacteria were isolated from both healthy and sheath blight infected leaf samples of rice plants, collected from different places of Malaysia, following dilution technique. Sheath blight pathogen was isolated from infected samples by tissue plating method. Out of 325, 14 isolates were found to be antagonist against the pathogen in pre evaluation test. All the 14 isolates were morphologically characterized. Antagonistic activity of these isolates was further confirmed by adopting the standard dual culture and extracellular metabolite tests. The best isolates were selected, based on the results. In dual culture test, the selected bacterial isolates KMB25, TMB33, PMB38, UMB20 and BMB42 showed 68.44%, 60.89%, 60.22%, 50.00% and 48.22% fungal growth inhibition, respectively and in extracellular metabolite test these bacterial isolates exhibited 93.33%, 84.26%, 69.82%, 67.96% and 39.26% of the same, respectively. Biochemical tests of selected isolates were performed following standard procedure. These bacterial isolates were tentatively identified as fluorescent pseudomonas by morphological and biochemical characterization. The identities were further confirmed by Biolog microstation system as P. fluorescens (UMB20), P. aeruginosa (KMB25, TMB33 and PMB38) and P. asplenii (BMB42) with similarity index ranging from 0.517 to 0.697. The effective bacterial isolates obtained from the present study can be used in the management of soil borne fungal pathogen Rhizoctonia solani, causing sheath blight of rice. PMID:25522511
Non-cytotoxic antifungal agents: isolation and structures of gageopeptides A-D from a Bacillus strain 109GGC020.
Tareq, Fakir Shahidullah; Lee, Min Ah; Lee, Hyi-Seung; Lee, Yeon-Ju; Lee, Jong Seok; Hasan, Choudhury M; Islam, Md Tofazzal; Shin, Hee Jae
Antifungal resistance and toxicity problems of conventional fungicides highlighted the requirement of search for new safe antifungal agents. To comply with the requirement, we discovered four new non-cytotoxic lipopeptides, gageopeptides A-D, 1-4, from a marine-derived bacterium Bacillus subtilis. The structures and stereochemistry of gageopeptides were determined by NMR data analysis and chemical means. Gageopeptides exhibited significant antifungal activities against pathogenic fungi Rhizoctonia solani, Botrytis cinerea, and Colletotrichum acutatum with minimum inhibitory concentration (MIC) values of 0.02-0.06 ?M. In addition, these lipopeptides showed significant motility inhibition and lytic activities against zoospores of the late blight pathogen Phytophthora capsici. These compounds also showed potent antimicrobial activity against Gram positive and Gram negative bacteria with MIC values of 0.04-0.08 ?M. However, gageopeptides A-D did not exhibit any cytotoxicity (GI50 > 25 ?M) against cancer cell lines in sulforhodamine B (SRB), 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT), and WST-1 ((4-[3-4-iodophenyl]-2-(4-nitrophenyl)-2H-5-tetrazolio)-1,3-benzene disulfonate)) assays, demonstrating that these compounds could be promising candidates for the development of non-cytotoxic antifungal agents. PMID:24857413
Heterologous expression of the antifungal ?-chitin binding protein CBP24 from bacillus thuringiensis and its synergistic action with bacterial chitinases.
Mehmood, Muhammad A; Latif, Mamoona; Hussain, Khadim; Gull, Munazza; Latif, Farooq; Rajoka, Muhammad I
The genome sequence analysis of Bacillus thuringiensis serovar konkukian S4 has shown to contain two chitinases (Chi74, Chi39) and two chitin-binding proteins (CBP50 and CBP24). The Chi74, Chi39 and CBP50 have been characterized previously. The chitin-binding protein CBP24 was cloned and heterologously expressed in Escherichia coli. The recombinant protein was purified using a Ni-NTA purification system. The purified protein was used to study its substrate binding activity using crystalline chitin variants as substrates. The Bmax and Kd values have shown that it preferably binds to ?-type of the crystalline chitin at a range of pH with peak activity between 5.5-7.5. To elucidate the role of CBP24 in the chitin degradation system of S4, the purified chitinases Chi74, Chi39 along with the ChiA from Serratia proteamcualans were used in different combinations with the CBP24 and chitinolytic activity was assayed. It was shown that the CBP24 acts synergistically with chitin degradation activity of bacterial chitinases non-specifically. Moreover, the CBP24 has shown antifungal activity against plant pathogenic fungi Fusarium oxysporum and Rhizoctonia solani. The present study will lead us to develop a technology for environmental friendly conversion of chitin to valuable products. PMID:25182053
Lignin and lignans in plant defence: insight from expression profiling of cinnamyl alcohol dehydrogenase genes during development and following fungal infection in Populus.
Bagniewska-Zadworna, Agnieszka; Barakat, Abdelali; Lakomy, Piotr; Smoli?ski, Dariusz J; Zadworny, Marcin
Cinnamyl alcohol dehydrogenase (CAD) catalyses the final step in the biosynthesis of monolignol, the main component of lignin. Lignins, deposited in the secondary cell wall, play a role in plant defence against pathogens. We re-analysed the phylogeny of CAD/CAD-like genes using sequences from recently sequenced genomes, and analysed the temporal and spatial expression profiles of CAD/CAD-like genes in Populus trichocarpa healthy and infected plants. Three fungal pathogens (Rhizoctonia solani, Fusarium oxysporum, and Cytospora sp.), varying in lifestyle and pathogenicity, were used for plant infection. Phylogenetic analyses showed that CAD/CAD-like genes were distributed in classes represented by all members from angiosperm lineages including basal angiosperms and Selaginella. The analysed genes showed different expression profiles during development and demonstrated that three genes were involved in primary xylem maturation while five may function in secondary xylem formation. Expression analysis following inoculation with fungal pathogens, showed that five genes were induced in either stem or leaves. These results add further evidence that CAD/CAD-like genes have evolved specialised functions in plant development and defence against various pest and pathogens. Two genes (PoptrCAD11 and PoptrCAD15), which were induced under various stresses, could be treated as universal markers of plant defence using lignification or lignan biosynthesis. PMID:25443838
Design, synthesis and fungicidal activities of some novel pyrazole derivatives.
Liu, Xue-Ru; Wu, Hua; He, Ze-Yu; Ma, Zhi-Qing; Feng, Jun-Tao; Zhang, Xing
In order to discover new compounds with good fungicidal activities, 32 pyrazole derivatives were designed and synthesized. The structures of the target compounds were confirmed by 1H-NMR, 13C-NMR, and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and their fungicidal activities against Botrytis cinerea, Rhizoctonia solani Kuhn, Valsa mali Miyabe et Yamada, Thanatephorus cucumeris (Frank) Donk, Fusarium oxysporum (S-chl) f.sp. cucumerinum Owen, and Fusarium graminearum Schw were tested. The bioassay results indicated that most of the derivatives exhibited considerable antifungal activities, especially compound 26 containing a p-trifluoromethyl- phenyl moiety showed the highest activity, with EC50 values of 2.432, 2.182, 1.787, 1.638, 6.986, and 6.043 ?g/mL against B. cinerea, R. solani, V. mali, T. cucumeris, F. oxysporum, and F. graminearum, respectively. Moreover, the activities of compounds such as compounds 27-32 were enhanced by introducing isothiocyanate and carboxamide moieties to the 5-position of the pyrazole ring. PMID:25203055
Plant growth promoting bacteria from cow dung based biodynamic preparations.
Radha, T K; Rao, D L N
Indigenous formulations based on cow dung fermentation are commonly used in organic farming. Three biodynamic preparations viz., Panchagavya (PG), BD500 and 'Cow pat pit' (CPP) showed high counts of lactobacilli (10(9) ml(-1)) and yeasts (10(4) ml(-1)). Actinomycetes were present only in CPP (10(4) ml(-1)) and absent in the other two. Seven bacterial isolates from these ferments were identified by a polyphasic approach: Bacillus safensis (PG1), Bacillus cereus (PG2, PG4 PG5), Bacillus subtilis (BD2) Lysinibacillus xylanilyticus (BD3) and Bacillus licheniformis (CPP1). This is the first report of L. xylanilyticus and B. licheniformis in biodynamic preparations. Only three carbon sources-dextrose, sucrose and trehalose out of 21 tested were utilized by all the bacteria. None could utilize arabinose, dulcitol, galactose, inositol, inulin, melibiose, raffinose, rhamnose and sorbitol. All the strains produced indole acetic acid (1.8-3.7 ?g ml(-1) culture filtrate) and ammonia. None could fix nitrogen; but all except B. safensis and B. licheniformis could solubilize phosphorous from insoluble tri-calcium phosphate. All the strains except L. xylaniliticus exhibited antagonism to the plant pathogen Rhizoctonia bataticola whereas none could inhibit Sclerotium rolfsi. In green house experiment in soil microcosms, bacterial inoculation significantly promoted growth of maize; plant dry weight increased by ~21 % due to inoculation with B. cereus (PG2). Results provide a basis for understanding the beneficial effects of biodynamic preparations and industrial deployment of the strains. PMID:25320439
Isolation and characteristics of protocatechuic acid from Paenibacillus elgii HOA73 against Botrytis cinerea on strawberry fruits.
Nguyen, Xuan Hoa; Naing, Kyaw Wai; Lee, Young Seong; Moon, Jae Hak; Lee, Jeong Hyun; Kim, Kil Yong
This study was undertaken to describe purification, identification, and characteristics of protocatechuic acid (PCA) isolated for the first time from Paenibacillus elgii HOA73 against Botrytis cinerea (the cause of gray mold disease on strawberry fruit). PCA was purified by different chromatographic techniques and identified as PCA (3,4-dihydroxybenzoic acid) by nuclear magnetic resonance and liquid chromatography-mass spectrometry analyses. PCA displayed potent antifungal activity against B. cinerea and Rhizoctonia solani. However, the antifungal activities were not sufficient to inhibit mycelial growth of Phytophthora capsici and Fusarium oxysporum. The minimum inhibitory concentration of PCA to inhibit any visible mycelial growth of both B. cinerea and R. solani was 64?µg?ml(-1) . Most B. cinerea conidia displayed altered shape and absence of germination, or were degraded after treatment with 50 and 100?µg?ml(-1) PCA, respectively. Moreover, gray mold formation on strawberry fruit was almost or completely inhibited by these PCA concentrations 7 days following infection with B. cinerea conidia, respectively. PCA may be a promising alternative to chemical fungicides as a potential biofungicide to prevent growth of B. cinerea in strawberry fruit disease management. PMID:25081931
Naturally produced citral can significantly inhibit normal physiology and induce cytotoxicity on Magnaporthe grisea.
Li, Rong-Yu; Wu, Xiao-Mao; Yin, Xian-Hui; Long, You-Hua; Li, Ming
Given the importance of finding alternatives to synthetic fungicides, the antifungal effects of natural product citral on six plant pathogenic fungi (Magnaporthe grisea, Gibberella zeae, Fusarium oxysporum, Valsa mali, Botrytis cinerea, and Rhizoctonia solani) were determined. Mycelial growth rate results showed that citral possessed high antifungal activities on those test fungi with EC50 values ranging from 39.52 to 193.00?µg/mL, which had the highest inhibition rates against M. grisea. Further action mechanism of citral on M. grisea was carried out. Citral treatment was found to alter the morphology of M. grisea hyphae by causing a loss of cytoplasm and distortion of mycelia. Moreover, citral was able to induce an increase in chitinase activity in M. grisea, indicating disruption of the cell wall. These results indicate that citral may act by disrupting cell wall integrity and membrane permeability, thus resulting in physiology changes and causing cytotoxicity. Importantly, the inhibitory effect of citral on M. grisea appears to be associated with its effects on mycelia reducing sugar, soluble protein, chitinase activity, pyruvate content, and malondialdehyde content. PMID:25752425
High-speed potato grading and quality inspection based on a color vision system
NASA Astrophysics Data System (ADS)
Noordam, Jacco C.; Otten, Gerwoud W.; Timmermans, Toine J. M.; van Zwol, Bauke H.
A high-speed machine vision system for the quality inspection and grading of potatoes has been developed. The vision system grades potatoes on size, shape and external defects such as greening, mechanical damages, rhizoctonia, silver scab, common scab, cracks and growth cracks. A 3-CCD line-scan camera inspects the potatoes in flight as they pass under the camera. The use of mirrors to obtain a 360-degree view of the potato and the lack of product holders guarantee a full view of the potato. To achieve the required capacity of 12 tons/hour, 11 SHARC Digital Signal Processors perform the image processing and classification tasks. The total capacity of the system is about 50 potatoes/sec. The color segmentation procedure uses Linear Discriminant Analysis (LDA) in combination with a Mahalanobis distance classifier to classify the pixels. The procedure for the detection of misshapen potatoes uses a Fourier based shape classification technique. Features such as area, eccentricity and central moments are used to discriminate between similar colored defects. Experiments with red and yellow skin-colored potatoes have shown that the system is robust and consistent in its classification.
Global protein-protein interaction network of rice sheath blight pathogen.
Lei, Ding; Lin, Runmao; Yin, Chuanchun; Li, Ping; Zheng, Aiping
Rhizoctonia solani is the major pathogenic fungi of rice sheath blight. It is responsible for the most serious disease of rice (Oryza sativa L.) and causes significant yield losses in rice-growing countries. Identifying the protein-protein interaction (PPI) maps of R. solani can provide insights into the potential pathogenic mechanisms and assign putative functions to unknown genes. Here, we exploited a PPI map of R. solani anastomosis group 1 IA (AG-1 IA) based on the interolog and domain-domain interaction methods. We constructed a core subset of high-confidence protein networks consisting of 6705 interactions among 1773 proteins. The high quality of the network was revealed by comprehensive methods, including yeast two-hybrid experiments. Pathogenic interaction subnetwork, secreted proteins subnetwork, and mitogen-activated protein kinase (MAPK) cascade subnetwork and their interacting partners were constructed and analyzed. Moreover, to exactly predict the pathogenic factors, the expression levels of the interaction proteins were investigated by analyzing RNA sequences that consisted of samples from the entire infection progress. The PPIs offer an exceptionally rich source of data that can be used to understand the gene functions and biological processes of this serious disease at the system level. PMID:24894516
Synthesis, antifungal activity and QSAR of some novel carboxylic acid amides.
Du, Shijie; Lu, Huizhe; Yang, Dongyan; Li, Hong; Gu, Xilin; Wan, Chuan; Jia, Changqing; Wang, Mian; Li, Xiuyun; Qin, Zhaohai
A series of novel aromatic carboxylic acid amides were synthesized and tested for their activities against six phytopathogenic fungi by an in vitro mycelia growth inhibition assay. Most of them displayed moderate to good activity. Among them N-(2-(1H-indazol-1-yl)phenyl)-2-(trifluoromethyl)benzamide (3c) exhibited the highest antifungal activity against Pythium aphanidermatum (EC50 = 16.75 µg/mL) and Rhizoctonia solani (EC50 = 19.19 µg/mL), compared to the reference compound boscalid with EC50 values of 10.68 and 14.47 µg/mL, respectively. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were employed to develop a three-dimensional quantitative structure-activity relationship model for the activity of the compounds. In the molecular docking, a fluorine atom and the carbonyl oxygen atom of 3c formed hydrogen bonds toward the hydroxyl hydrogens of TYR58 and TRP173. PMID:25749678
DNA interaction, antimicrobial, electrochemical and spectroscopic studies of metal(II) complexes with tridentate heterocyclic Schiff base derived from 2?-methylacetoacetanilide
NASA Astrophysics Data System (ADS)
Raman, Natarajan; Pothiraj, Krishnan; Baskaran, Thanasekaran
A new Schiff base ligand (HL) was synthesized by the condensation reaction between 2'-methyleacetoacetanilide and 2-amino-3-hydroxypyridine. Its Co(II), Ni(II), Cu(II) and Zn(II) complexes were prepared by the interaction of the ligand with metal(II) chloride. They were characterized by elemental analysis, IR, 1H NMR, EPR, UV-Vis, magnetic susceptibility measurements, conductivity measurements and FAB-mass spectra. The interaction of the complexes with calf thymus DNA (CT-DNA) has been investigated by UV absorption, viscosity and cyclic voltammetry methods, and the mode of CT-DNA binding to the complexes has been explored. Furthermore, the DNA cleavage activity by the complexes was performed. It was found to be oxidative hydroxyl radical cleavage in the presence of 3-mercaptopropionic acid (MPA). The Schiff base and its complexes have been screened for their antibacterial ( Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa) and antifungal ( Aspergillus niger, Rhizopus stolonifer, Rhizoctonia bataicola and Candida albicans) activities and the data reveal that the complexes have higher activity than the free ligand.
Antagonistic potential of native strain Streptomyces aurantiogriseus VSMGT1014 against sheath blight of rice disease.
Harikrishnan, Hariharan; Shanmugaiah, Vellasamy; Balasubramanian, Natesan; Sharma, Mahaveer P; Kotchoni, Simeon O
A total of 132 actinomycetes was isolated from different rice rhizosphere soils of Tamil Nadu, India, among which 57 showed antagonistic activity towards Rhizoctonia solani, which is sheath blight (ShB) pathogen of rice and other fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata with a variable zone of inhibition. Potential actinomycete strain VSMGT1014 was identified as Streptomyces aurantiogriseus VSMGT1014 based on the morphological, physiological, biochemical and 16S rRNA sequence analysis. The strain VSMGT1014 produced lytic enzymes, secondary metabolites, siderophore, volatile substance and indole acetic acid. Crude metabolites of VSMGT1014 showed activity against R. solani at 5 µg ml(-1); however, the prominent inhibition zone was observed from 40 to 100 µg ml(-1). Reduced lesion heights observed in culture, cells-free filtrate, crude metabolites and carbendazim on challenge with pathogen in the detached leaf assay. The high content screening test clearly indicated denucleation of R. solani at 5 µg ml(-1) treatment of crude metabolite and carbendazim respectively. The results conclude that strain VSMGT1014 was found to be a potential candidate for the control of ShB of rice as a bio fungicide. PMID:25304022
Identification of QTLs and possible candidate genes conferring sheath blight resistance in rice (Oryza sativa L.).
Yadav, Shailesh; Anuradha, Ghanta; Kumar, Ravi Ranjan; Vemireddy, Lakshminaryana Reddy; Sudhakar, Ravuru; Donempudi, Krishnaveni; Venkata, Durgarani; Jabeen, Farzana; Narasimhan, Yamini Kalinati; Marathi, Balram; Siddiq, Ebrahimali Abubacker
Sheath blight, caused by the pathogenic fungus Rhizoctonia solani Kühn, is one of the most devastating diseases in rice. Breeders have always faced challenges in acquiring reliable and absolute resistance to this disease in existing rice germplasm. In this context, 40 rice germplasm including eight wild, four landraces, twenty- six cultivated and two advanced breeding lines were screened utilizing the colonized bits of typha. Except Tetep and ARC10531 which expressed moderate level of resistance to the disease, none could be found to be authentically resistant. In order to map the quantitative trait loci (QTLs) governing the sheath blight resistance, two mapping populations (F2 and BC1F2) were developed from the cross BPT-5204/ARC10531. Utilizing composite interval mapping analysis, 9 QTLs mapped to five different chromosomes were identified with phenotypic variance ranging from 8.40 to 21.76%. Two SSR markers namely RM336 and RM205 were found to be closely associated with the major QTLs qshb7.3 and qshb9.2 respectively and were attested as well in BC1F2 population by bulk segregant analysis approach. A hypothetical ? 1-3 glucanase with other 31 candidate genes were identified in silico utilizing rice database RAP-DB within the identified QTL region qshb9.2. A detailed insight into these candidate genes will facilitate at molecular level the intricate nature of sheath blight, a step forward towards functional genomics. PMID:25977888
Synthesis, spectral, thermal and anti-fungal studies of organotin(IV) thiohydrazone complexes
NASA Astrophysics Data System (ADS)
Singh, Rajeev; Kaushik, N. K.
The reaction of tribenzyltin(IV) chloride and di( para-chlorobenzyl)tin(IV) dichloride with thiohydrazones derived by condensation of 2-phenylethyl N-thiohydrazide with benzaldehyde, salicaldehyde, p-methylacetophenone and cinnamaldehyde have been investigated in 1:1 molar ratio. These ligands act as neutral, bidentate species and coordinate to the central tin (IV) atom through the thiosulphur and azomethine nitrogen. The newly synthesized complexes have been characterized by elemental analysis and molecular weight determination. The mode of bonding of the complexes has been suggested on the basis of infrared, electronic and 1H NMR spectroscopy, and probable structures have been assigned to these complexes. Phenomenological and kinetic parameters have been calculated using thermogravimetric (TG) and differential thermal analytical (DTA) curves and their variations have been correlated with some structural parameters of the complexes. The ligands and their tin(IV) complexes have been screened in vitro for their fungicidal activity against Rhizoctonia solanii and Sclerotium rolfsii and found to be quite active in this respect.
Ieodoglucomide C and Ieodoglycolipid, New Glycolipids from a Marine-Derived Bacterium Bacillus licheniformis 09IDYM23.
Tareq, Fakir Shahidullah; Lee, Hyi-Seung; Lee, Yeon-Ju; Lee, Jong Seok; Shin, Hee Jae
Chemical examination of the ethyl acetate extract from the fermentation broth of the marine-derived bacterium Bacillus licheniformis resulted in the isolation of two new glycolipids, ieodoglucomide C (1) and ieodoglycolipid (2). The structural characterization of 1 and 2 was achieved by extensive spectroscopic evidence, including 2D NMR experiments. A combination of chemical derivatization techniques followed by NMR studies, LC-MS data analysis and a literature review was deployed for the establishment of the stereo-configurations of 1 and 2. Compounds 1 and 2 exhibited good antibiotic properties against Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Salmonella typhi, Escherichia coli and Pseudomonas aeruginosa with MICs ranging from 0.01 to 0.05 ?M. Furthermore, the antifungal activity of 1 and 2 was evaluated against plant pathogenic fungi Aspergillus niger, Rhizoctonia solani, Botrytis cinerea and Colletotrichum acutatum as well as the human pathogen Candida albicans. Compounds 1 and 2 inhibited the mycelial growth of these pathogens with MIC values of 0.03-0.05 ?M, revealing that these compounds are good candidates for the development of new fungicides. PMID:25893812
Design, synthesis, antifungal, and antioxidant activities of (E)-6-((2-phenylhydrazono)methyl)quinoxaline derivatives.
Zhang, Mao; Dai, Zhi-Cheng; Qian, Shao-Song; Liu, Jun-Yan; Xiao, Yu; Lu, Ai-Min; Zhu, Hai-Liang; Wang, Jian-Xin; Ye, Yong-Hao
Different substituted phenylhydrazone groups were linked to the quinoxaline scaffold to provide 26 compounds (6a-6z). Their structures were confirmed by (1)H and (13)C NMR, MS, elemental analysis, and X-ray single-crystal diffraction. The antifungal activities of these compounds against Rhizoctonia solani were evaluated in vitro. Compound 6p is the most promising one among all the tested compounds with an EC50 of 0.16 ?g·mL(-1), more potent than the coassayed positive control fungicide carbendazim (EC50: 1.42 ?g·mL(-1)). In addition, these compounds were subjected to antioxidant assay by employing diphenylpicrylhydrazyl (DPPH) and mice microsome lipid peroxidation (LPO) methods. Most of these compounds are potent antioxidants. The strongest compounds are 6e (EC50: 7.60 ?g·mL(-1), DPPH) and 6a (EC50: 0.96 ?g·mL(-1), LPO), comparative to or more potent than the positive control Trolox [EC50: 5.90 ?g·mL(-1) (DPPH) and 18.23 ?g·mL(-1) (LPO)]. The structure and activity relationships were also discussed. PMID:25229541
Activation of Pathogenesis-related Genes by the Rhizobacterium, Bacillus sp. JS, Which Induces Systemic Resistance in Tobacco Plants.
Kim, Ji-Seong; Lee, Jeongeun; Lee, Chan-Hui; Woo, Su Young; Kang, Hoduck; Seo, Sang-Gyu; Kim, Sun-Hyung
Plant growth promoting rhizobacteria (PGPR) are known to confer disease resistance to plants. Bacillus sp. JS demonstrated antifungal activities against five fungal pathogens in in vitro assays. To verify whether the volatiles of Bacillus sp. JS confer disease resistance, tobacco leaves pre-treated with the volatiles were damaged by the fungal pathogen, Rhizoctonia solani and oomycete Phytophthora nicotianae. Pre-treated tobacco leaves had smaller lesion than the control plant leaves. In pathogenesis-related (PR) gene expression analysis, volatiles of Bacillus sp. JS caused the up-regulation of PR-2 encoding ?-1,3-glucanase and acidic PR-3 encoding chitinase. Expression of acidic PR-4 encoding chitinase and acidic PR-9 encoding peroxidase increased gradually after exposure of the volatiles to Bacillus sp. JS. Basic PR-14 encoding lipid transfer protein was also increased. However, PR-1 genes, as markers of salicylic acid (SA) induced resistance, were not expressed. These results suggested that the volatiles of Bacillus sp. JS confer disease resistance against fungal and oomycete pathogens through PR genes expression. PMID:26060440
A novel fungal metabolite with beneficial properties for agricultural applications.
Vinale, Francesco; Manganiello, Gelsomina; Nigro, Marco; Mazzei, Pierluigi; Piccolo, Alessandro; Pascale, Alberto; Ruocco, Michelina; Marra, Roberta; Lombardi, Nadia; Lanzuise, Stefania; Varlese, Rosaria; Cavallo, Pierpaolo; Lorito, Matteo; Woo, Sheridan L
Trichoderma are ubiquitous soil fungi that include species widely used as biocontrol agents in agriculture. Many isolates are known to secrete several secondary metabolites with different biological activities towards plants and other microbes. Harzianic acid (HA) is a T. harzianum metabolite able to promote plant growth and strongly bind iron. In this work, we isolated from the culture filtrate of a T. harzianum strain a new metabolite, named isoharzianic acid (iso-HA), a stereoisomer of HA. The structure and absolute configuration of this compound has been determined by spectroscopic methods, including UV-Vis, MS, 1D and 2D NMR analyses. In vitro applications of iso-HA inhibited the mycelium radial growth of Sclerotinia sclerotiorum and Rhizoctonia solani. Moreover, iso HA improved the germination of tomato seeds and induced disease resistance. HPLC-DAD experiments showed that the production of HA and iso HA was affected by the presence of plant tissue in the liquid medium. In particular, tomato tissue elicited the production of HA but negatively modulated the biosynthesis of its analogue iso-HA, suggesting that different forms of the same Trichoderma secondary metabolite have specific roles in the molecular mechanism regulating the Trichoderma plant interaction. PMID:25006784
Characterization of Bacillus isolates of potato rhizosphere from andean soils of Peru and their potential PGPR characteristics.
Calvo, Pamela; Ormeńo-Orrillo, Ernesto; Martínez-Romero, Esperanza; Zúńiga, Doris
Bacillus spp. are well known rhizosphere residents of many crops and usually show plant growth promoting (PGP) activities that include biocontrol capacity against some phytopatogenic fungi. Potato crops in the Andean Highlands of Peru face many nutritional and phytophatogenic problems that have a significant impact on production. In this context is important to investigate the natural presence of these microorganisms in the potato rhizosphere and propose a selective screening to find promising PGP strains. In this study, sixty three Bacillus strains isolated from the rhizosphere of native potato varieties growing in the Andean highlands of Peru were screened for in vitro antagonism against Rhizoctonia solani and Fusarium solani. A high prevalence (68%) of antagonists against R. solani was found. Ninety one percent of those strains also inhibited the growth of F. solani. The antagonistic strains were also tested for other plant growth promotion activities. Eighty one percent produced some level of the auxin indole-3-acetic acid, and 58% solubilized tricalcium phosphate. Phylogenetic analysis revealed that the majority of the strains belonged to the B. amyloliquefaciens species, while strains Bac17M11, Bac20M1 and Bac20M2 may correspond to a putative new Bacillus species. The results suggested that the rhizosphere of native potatoes growing in their natural habitat in the Andes is a rich source of Bacillus fungal antagonists, which have a potential to be used in the future as PGP inoculants to improve potato crop. PMID:24031569
Characterization of Bacillus isolates of potato rhizosphere from andean soils of Peru and their potential PGPR characteristics
Calvo, Pamela; Ormeńo-Orrillo, Ernesto; Martínez-Romero, Esperanza; Zúńiga, Doris
Bacillus spp. are well known rhizosphere residents of many crops and usually show plant growth promoting (PGP) activities that include biocontrol capacity against some phytopatogenic fungi. Potato crops in the Andean Highlands of Peru face many nutritional and phytophatogenic problems that have a significant impact on production. In this context is important to investigate the natural presence of these microorganisms in the potato rhizosphere and propose a selective screening to find promising PGP strains. In this study, sixty three Bacillus strains isolated from the rhizosphere of native potato varieties growing in the Andean highlands of Peru were screened for in vitro antagonism against Rhizoctonia solani and Fusarium solani. A high prevalence (68%) of antagonists against R. solani was found. Ninety one percent of those strains also inhibited the growth of F. solani. The antagonistic strains were also tested for other plant growth promotion activities. Eighty one percent produced some level of the auxin indole-3-acetic acid, and 58% solubilized tricalcium phosphate. Phylogenetic analysis revealed that the majority of the strains belonged to the B. amyloliquefaciens species, while strains Bac17M11, Bac20M1 and Bac20M2 may correspond to a putative new Bacillus species. The results suggested that the rhizosphere of native potatoes growing in their natural habitat in the Andes is a rich source of Bacillus fungal antagonists, which have a potential to be used in the future as PGP inoculants to improve potato crop. PMID:24031569
Overlapping and distinct functions of two Trichoderma virens MAP kinases in cell-wall integrity, antagonistic properties and repression of conidiation.
Kumar, Ashish; Scher, Keren; Mukherjee, Mala; Pardovitz-Kedmi, Ella; Sible, George V; Singh, Uma S; Kale, Sharad P; Mukherjee, Prasun K; Horwitz, Benjamin A
We have studied the functions of the Trichoderma virens TmkB, a homologue of the yeast cell-wall integrity MAP kinase Slt2, using gene knockout. The functions of TmkB were compared to those of the pathogenicity MAP kinase homologue (TmkA). Like the tmkA loss-of-function mutants, tmkB mutants exhibited reduced radial growth and constitutive conidiation in dark as well as in liquid shake cultures. The tmkB mutants, in contrast to tmkA mutants, had cell-wall integrity defects, as shown by autolysis of the mycelia and increased sensitivity to cell-wall degrading enzymes. Interestingly, the tmkB mutants were not autolytic on the synthetic Vogels minimal medium. The tmkB mutants had attenuated ability to overgrow the plant pathogen Sclerotium rolfsii, while retaining the ability to overgrow Rhizoctonia solani and Pythium spp., a phenotype also exhibited by the tmkA mutants. This first functional analysis of a cell-wall integrity MAPK in Trichoderma spp., a group of economically important fungi, shows the importance of this signaling pathway in biocontrol. Common phenotypes of the TmkA and TmkB pathways suggest that the two MAPKs may share some substrates, perhaps subunits of key transcription factors, thus dependent on two phosphorylation events for their activity. PMID:20633533
Marine Isolates of Trichoderma spp. as Potential Halotolerant Agents of Biological Control for Arid-Zone Agriculture ? †
Gal-Hemed, Inbal; Atanasova, Lea; Komon-Zelazowska, Monika; Druzhinina, Irina S.; Viterbo, Ada; Yarden, Oded
The scarcity of fresh water in the Mediterranean region necessitates the search for halotolerant agents of biological control of plant diseases that can be applied in arid-zone agriculture irrigated with saline water. Among 29 Trichoderma strains previously isolated from Mediterranean Psammocinia sp. sponges, the greatest number of isolates belong to the Trichoderma longibrachiatum-Hypocrea orientalis species pair (9), H. atroviridis/T. atroviride (9), and T. harzianum species complex (7), all of which are known for high mycoparasitic potential. In addition, one isolate of T. asperelloides and two putative new species, Trichoderma sp. O.Y. 14707 and O.Y. 2407, from Longibrachiatum and Strictipilosa clades, respectively, have been identified. In vitro salinity assays showed that the ability to tolerate increasing osmotic pressure (halotolerance) is a strain- or clade-specific property rather than a feature of a species. Only a few isolates were found to be sensitive to increased salinity, while others either were halotolerant or even demonstrated improved growth in increasingly saline conditions. In vitro antibiosis assays revealed strong antagonistic activity toward phytopathogens due to the production of both soluble and volatile metabolites. Two marine-derived Trichoderma isolates, identified as T. atroviride and T. asperelloides, respectively, effectively reduced Rhizoctonia solani damping-off disease on beans and also induced defense responses in cucumber seedlings against Pseudomonas syringae pv. lachrimans. This is the first inclusive evaluation of marine fungi as potential biocontrol agents. PMID:21666030
Cloning of Genes Involved in the Synthesis of Pyrrolnitrin from Pseudomonas fluorescens and Role of Pyrrolnitrin Synthesis in Biological Control of Plant Disease
Hill, D. S.; Stein, J. I.; Torkewitz, N. R.; Morse, A. M.; Howell, C. R.; Pachlatko, J. P.; Becker, J. O.; Ligon, J. M.
A soil isolate of Pseudomonas fluorescens (BL915) was shown to be an effective antagonist of Rhizoctonia solani-induced damping-off of cotton. Investigation of the biological basis of this antagonism revealed that the strain produces pyrrolnitrin, a secondary metabolite known to inhibit R. solani and other fungi. Mutants of strain BL915 that did not produce pyrrolnitrin and did not suppress damping-off of cotton by R. solani were generated by exposure to N-methyl-N? -nitro-N-nitrosoguanidine. A gene region that was capable of restoring pyrrolnitrin production to the non-pyrrolnitrin-producing mutants and of conferring this ability upon two other P. fluorescens strains not otherwise known to produce this compound or to be capable of suppressing damping-off caused by R. solani was isolated from strain BL915. The non-pyrrolnitrin-producing strains (mutants of BL915 and the other two P. fluorescens strains) which synthesized pyrrolnitrin after the introduction of the gene region from strain BL915 were also shown to be equal to strain BL915 in their ability to suppress R. solani-induced damping-off of cotton. These results indicate that we have isolated from P. fluorescens BL915 a gene(s) that has a role in the synthesis of pyrrolnitrin and that the production of this compound has a role in the ability of this strain to control damping-off of cotton by R. solani. PMID:16349167
Ocatin. A novel tuber storage protein from the andean tuber crop oca with antibacterial and antifungal activities.
Flores, Teresita; Alape-Girón, Alberto; Flores-Díaz, Marietta; Flores, Hector E
The most abundant soluble tuber protein from the Andean crop oca (Oxalis tuberosa Mol.), named ocatin, has been purified and characterized. Ocatin accounts for 40% to 60% of the total soluble oca tuber proteins, has an apparent molecular mass of 18 kD and an isoelectric point of 4.8. This protein appears to be found only in tubers and is accumulated only within the cells of the pith and peridermis layers (peel) of the tuber as it develops. Ocatin inhibits the growth of several phytopathogenic bacteria (Agrobacterium tumefaciens, Agrobacterium radiobacter, Serratia marcescens, and Pseudomonas aureofaciens) and fungi (Phytophthora cinnamomi, Fusarium oxysporum, Rhizoctonia solani, and Nectria hematococcus). Ocatin displays substantial amino acid sequence similarity with a widely distributed group of intracellular pathogenesis-related proteins with a hitherto unknown biological function. Our results showed that ocatin serves as a storage protein, has antimicrobial properties, and belongs to the Betv 1/PR-10/MLP protein family. Our findings suggest that an ancient scaffolding protein was recruited in the oca tuber to serve a storage function and that proteins from the Betv 1/PR-10/MLP family might play a role in natural resistance to pathogens. PMID:11950978
Screening for anti-infective properties of several medicinal plants of the Mauritians flora.
Rangasamy, Oumadevi; Raoelison, Guy; Rakotoniriana, Francisco E; Cheuk, Kiban; Urverg-Ratsimamanga, Suzanne; Quetin-Leclercq, Joelle; Gurib-Fakim, Ameenah; Subratty, Anwar Hussein
Several plants of the Mauritian flora alleged to possess anti-infective properties were studied against different strains of pathogenic bacteria and fungi. The grounded dried plant materials were extracted with different extractants and screened for anti-microbial activity using the disk diffusion and the micro-dilution techniques. Preliminary screening revealed that the methanol extracts were most active. Salmonella enteritidis, Enterobacter cloacae and Bacillus subtilis were the three test organisms, which were found to be susceptible to all the crude methanolic extracts of the different plants investigated (100% susceptibility), followed by Escherichia coli (57.1%) and Pseudomonas aeruginosa (57.1%), and Staphylococcus aureus (28.6%). The lowest minimum inhibitory concentration recorded for the different crude methanol extracts against Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Enterobacter cloacae, Bacillus subtilis and the mould fungus Candida albicans were 500, 1000, 125, 250, 1000 and 125 micro g/ml, respectively. Bioautography using Cladosporium cucumerinum revealed that dichloromethane (DCM) extracts had the highest activity against the phytopathogenic fungus. It was also noted that the DCM extracts of Michelia champaca and Antidesma madagascariense yielded the maximum number of growth inhibiting compounds against Cladosporium cucumerinum. Activity of the different crude extracts was also investigated against several phytopathogenic filamentous fungi, Colletotrichum glocosporoides, Rhizoctonia solani, Sclerotinia sclerotium, Guignardia sp. and Fusarium oxysporum. It was found that crude hexane extracts as well as crude DCM extracts exhibited marked activity against several strains of fungi, especially Colletotrichum glocosporoides, Sclerotinia sclerotium and Guignardia sp. PMID:17011733
Interaction of Rotylenchulus reniformis with Seedling Disease Pathogens of Cotton
Palmateer, A. J.; Lawrence, K. S.; van Santen, E.; Morgan-Jones, G.
The impact of 10 Fusarium species in concomitant association with Rotylenchulus reniformis on cotton seedling disease was examined under greenhouse conditions. In experiment 1, fungal treatments consisted of Fusarium chlamydosporum, F. equiseti, F. lateritium, F. moniliforme, F. oxysporum, F. oxysporum f.sp. vasinfectum, F. proliferatum, F. semitectum, F. solani, and F. sporotrichioides; Rhizoctonia solani; and Thielaviopsis basicola. The experimental design was a 2 × 14 factorial consisting of the presence or absence of R. reniformis and the 12 fungal treatments plus two controls in autoclaved field soil. In experiment 2, the same fungal and nematode treatments were examined in autoclaved or non-autoclaved soil. This experimental design was a 2 × 2 × 14 factorial consisting of field or autoclaved soil, presence or absence of R. reniformis, and the 12 fungal treatments plus two controls. In both tests, Fusarium oxysporum f. sp. vasinfectum, F. solani, R. solani, and T. basicola consistently displayed extensive root and hypocotyl necrosis that was more severe (P ? 0.05) in the presence of R. reniformis. Soil treatment (autoclaved vs. non-autoclaved) influenced the impact of the Fusarium species on cotton seedling disease, with disease being more severe in the autoclaved soil. Rotylenchulus reniformis reproduction on cotton seedlings was greater in field soil compared to autoclaved soil (P ? 0.05). This study suggests the importance of Fusarium species and R. reniformis in cotton seedling disease. PMID:19262802
Resistance against various fungal pathogens and reniform nematode in transgenic cotton plants expressing Arabidopsis NPR1.
Parkhi, Vilas; Kumar, Vinod; Campbell, LeAnne M; Bell, Alois A; Shah, Jyoti; Rathore, Keerti S
Cotton is an economically important crop worldwide that suffers severe losses due to a wide range of fungal/bacterial pathogens and nematodes. Given its susceptibility to various pathogens, it is important to obtain a broad-spectrum resistance in cotton. Resistance to several fungal and bacterial diseases has been obtained by overexpressing the Non-expressor of Pathogenesis-Related genes-1 (NPR1) in various plant species with apparently minimal or no pleiotropic effects. We examined the efficacy of this approach in cotton by constitutive expression of the Arabidopsis (Arabidopsis thaliana) NPR1 gene. The results show that NPR1-expressing lines exhibited significant resistance to Verticillium dahliae isolate TS2, Fusarium oxysporum f. sp. vasinfectum, Rhizoctonia solani, and Alternaria alternata. Interestingly, the transformants also showed significant resistance to reniform nematodes. Analysis of defense-related, biochemical and molecular responses suggest that when challenged with pathogens or certain systemic acquired resistance-inducing chemicals, the transgenic lines respond to a greater degree compared to the wild-type plants. Importantly, the basal activities of the defense-related genes and enzymes in uninduced transformants were no different than those in their non-transgenic counterparts. The results provide additional evidence supporting the role of NPR1 as an important part of the plant defense system and suggest a means to achieve broad-spectrum resistance to pathogens via genetic engineering. PMID:20151323
Evaluation of antimicrobial activity of endophytic fungi from Camptotheca acuminata (Nyssaceae).
Ding, T; Jiang, T; Zhou, J; Xu, L; Gao, Z M
Agricultural research of plant-derived endophytic fungi has grown in recent decades. We isolated 26 endophytic fungi from the leaves, stems and fruits of "the tree of life", Camptotheca acuminata, and tested them for antimicrobial activities based on growth inhibition measurements in a modified agar diffusion method. Fermentation broths from most of the isolates exhibited antifungal activity and 50% exhibited antibacterial activity; some of them also exhibited strong broad-spectrum antimicrobial activity. The strongest antimicrobial activity was exhibited by strains XSY10 and XSY15 against Rhizoctonia solani and Fusarium oxysporum f. sp. vasinfectum, with 75% and 67% inhibition, respectively. Strain XSJ01 gave strong activity against pathogenic bacteria, with inhibition zones more than 20 mm in diameter. The isolates were identified by molecular methods as belonging to nine taxa: Nigrospora, Diaporthe, Alternaria, Colletotrichum, Pestalotiopsis, Sordariomycete, Guignardiai, Penicillium, and Zythia. Based on these results, we conclude that the endophytic fungi of C. acuminata are promising sources of novel bioactive compounds. PMID:21038296
Colonization and persistence of a plant growth-promoting bacterium Pseudomonas fluorescens strain CS85, on roots of cotton seedlings.
Wang, Chunxia; Wang, Daoben; Zhou, Qi
Pseudomonas fluorescens CS85, which was previously isolated from the rhizosphere of cotton seedlings, acts as both a plant growth-promoting bacterium and a biocontrol agent against cotton pathogens, including Rhizoctonia solani, Colletotrichum gossypii, Fusarium oxysporum f sp. vasinfectum, and Verticillium dahliae. Strain CS85 was labeled separately with luxAB and gusA. The labeled strains were stably maintained and had high levels of expression of the marker genes, luxAB and gusA, after successive transfers on nonselective medium, long-term preservation, and after recovery from soil. The labeled strains displayed similar biocontrol characteristics (e.g., antibiosis, effects of growth-promotion and disease-control) to the original strain. The labeled strains colonized all surfaces of the young plant root zones, such as roots hairs and lateral roots, although the distribution of the labeled strains on the root surfaces was not uniform. Moreover, the population densities of the labeled strains on the root surface were stably maintained at high levels during the first 2 weeks of plant growth in the native soil, so that about 10(7)-10(8) CFU/g root were detected, then decreased gradually. Nevertheless, approximately 10(6) CFU/g root of the labeled strains were observed on the root surfaces 35 d after planting. PMID:15381971
Interaction of Rotylenchulus reniformis with Seedling Disease Pathogens of Cotton.
Palmateer, A J; Lawrence, K S; van Santen, E; Morgan-Jones, G
The impact of 10 Fusarium species in concomitant association with Rotylenchulus reniformis on cotton seedling disease was examined under greenhouse conditions. In experiment 1, fungal treatments consisted of Fusarium chlamydosporum, F. equiseti, F. lateritium, F. moniliforme, F. oxysporum, F. oxysporum f.sp. vasinfectum, F. proliferatum, F. semitectum, F. solani, and F. sporotrichioides; Rhizoctonia solani; and Thielaviopsis basicola. The experimental design was a 2 x 14 factorial consisting of the presence or absence of R. reniformis and the 12 fungal treatments plus two controls in autoclaved field soil. In experiment 2, the same fungal and nematode treatments were examined in autoclaved or non-autoclaved soil. This experimental design was a 2 x 2 x 14 factorial consisting of field or autoclaved soil, presence or absence of R. reniformis, and the 12 fungal treatments plus two controls. In both tests, Fusarium oxysporum f. sp. vasinfectum, F. solani, R. solani, and T. basicola consistently displayed extensive root and hypocotyl necrosis that was more severe (P = 0.05) in the presence of R. reniformis. Soil treatment (autoclaved vs. non-autoclaved) influenced the impact of the Fusarium species on cotton seedling disease, with disease being more severe in the autoclaved soil. Rotylenchulus reniformis reproduction on cotton seedlings was greater in field soil compared to autoclaved soil (P = 0.05). This study suggests the importance of Fusarium species and R. reniformis in cotton seedling disease. PMID:19262802
Linkage map construction in allotetraploid creeping bentgrass (Agrostis stolonifera L.).
Chakraborty, N; Bae, J; Warnke, S; Chang, T; Jung, G
Creeping bentgrass (Agrostis stolonifera L.) is one of the most adapted bentgrass species for use on golf course fairways and putting greens because of its high tolerance to low mowing height. It is a highly outcrossing allotetraploid species (2n=4x=28, A(2) and A(3) subgenomes). The first linkage map in this species is reported herein, and it was constructed based on a population derived from a cross between two heterozygous clones using 169 RAPD, 180 AFLP, and 39 heterologous cereal and 36 homologous bentgrass cDNA RFLP markers. The linkage map consists of 424 mapped loci covering 1,110 cM in 14 linkage groups, of which seven pairs of homoeologous chromosomes were identified based on duplicated loci. The numbering of all seven linkage groups in the bentgrass map was assigned according to common markers mapped on syntenous chromosomes of ryegrass and wheat. The number of markers linked in coupling and repulsion phase was in a 1:1 ratio, indicating disomic inheritance. This supports a strict allotetraploid inheritance in creeping bentgrass, as suggested by previous work based on chromosomal pairing and isozymes. This linkage map will assist in the tagging and eventually in marker-assisted breeding of economically important quantitative traits like disease resistance to dollar spot (Sclerotinia homoeocarpa F.T. Bennett) and brown patch (Rhizoctonia solani Kuhn). PMID:15981010
Diversities in Virulence, Antifungal Activity, Pigmentation and DNA Fingerprint among Strains of Burkholderia glumae
Karki, Hari S.; Shrestha, Bishnu K.; Han, Jae Woo; Groth, Donald E.; Barphagha, Inderjit K.; Rush, Milton C.; Melanson, Rebecca A.; Kim, Beom Seok; Ham, Jong Hyun
Burkholderia glumae is the primary causal agent of bacterial panicle blight of rice. In this study, 11 naturally avirulent and nine virulent strains of B. glumae native to the southern United States were characterized in terms of virulence in rice and onion, toxofalvin production, antifungal activity, pigmentation and genomic structure. Virulence of B. glumae strains on rice panicles was highly correlated to virulence on onion bulb scales, suggesting that onion bulb can be a convenient alternative host system to efficiently determine the virulence of B. glumae strains. Production of toxoflavin, the phytotoxin that functions as a major virulence factor, was closely associated with the virulence phenotypes of B. glumae strains in rice. Some strains of B. glumae showed various levels of antifungal activity against Rhizoctonia solani, the causal agent of sheath blight, and pigmentation phenotypes on casamino acid-peptone-glucose (CPG) agar plates regardless of their virulence traits. Purple and yellow-green pigments were partially purified from a pigmenting strain of B. glumae, 411gr-6, and the purple pigment fraction showed a strong antifungal activity against Collectotrichum orbiculare. Genetic variations were detected among the B. glumae strains from DNA fingerprinting analyses by repetitive element sequence-based PCR (rep-PCR) for BOX-A1R-based repetitive extragenic palindromic (BOX) or enterobacterial repetitive intergenic consensus (ERIC) sequences of bacteria; and close genetic relatedness among virulent but pigment-deficient strains were revealed by clustering analyses of DNA fingerprints from BOX-and ERIC-PCR. PMID:23028972
Effects of Rapeseed and Vetch as Green Manure Crops and Fallow on Nematodes and Soil-borne Pathogens
Johnson, A. W.; Golden, A. M.; Auld, D. L.; Sumner, D. R.
In a rapeseed-squash cropping system, Meloidogyne incognita race 1 and M. javanica did not enter, feed, or reproduce in roots of seven rapeseed cultivars. Both nematode species reproduced at low levels on roots of the third crop of rapeseed. Reproduction of M. incognita and M. javanica was high on squash following rapeseed, hairy vetch, and fallow. The application of fenamiphos suppressed (P = 0.05) root-gall indices on squash following rapeseed, hairy vetch, and fallow; and on Dwarf Essex and Cascade rapeseed, but not Bridger and Humus rapeseed in 1987. The incorporation of 30-61 mt/ha green biomass of rapeseed into the soil 6 months after planting did not affect the population densities of Criconemella ornata, M. incognita, M. javanica, Pythium spp., Rhizoctonia solani AG-4; nor did it consistently increase yield of squash. Hairy vetch supported larger numbers of M. incognita and M. javanica than rapeseed cultivars or fallow. Meloidogyne incognita and M. javanica survived in fallow plots in the absence of a host from October to May each year at a level sufficient to warrant the use of a nematicide to manage nematodes on the following susceptible crop. PMID:19283212
Effect of Biocontrol Agent Pseudomonas fluorescens 2P24 on Soil Fungal Community in Cucumber Rhizosphere Using T-RFLP and DGGE
Gao, Guanpeng; Yin, Danhan; Chen, Shengju; Xia, Fei; Yang, Jie; Li, Qing; Wang, Wei
Fungi and fungal community play important roles in the soil ecosystem, and the diversity of fungal community could act as natural antagonists of various plant pathogens. Biological control is a promising method to protect plants as chemical pesticides may cause environment pollution. Pseudomonas fluorescens 2P24 had strong inhibitory on Rastonia solanacearum, Fusarium oxysporum and Rhizoctonia solani, etc., and was isolated from the wheat rhizosphere take-all decline soils in Shandong province, China. However, its potential effect on soil fungal community was still unknown. In this study, the gfp-labeled P. fluorescens 2P24 was inoculated into cucumber rhizosphere, and the survival of 2P24 was monitored weekly. The amount decreased from 108 to 105 CFU/g dry soils. The effect of 2P24 on soil fungal community in cucumber rhizosphere was investigated using T-RFLP and DGGE. In T-RFLP analysis, principle component analysis showed that the soil fungal community was greatly influenced at first, digested with restriction enzyme Hinf I and Taq I. However, there was little difference as digested by different enzymes. DGGE results demonstrated that the soil fungal community was greatly shocked at the beginning, but it recovered slowly with the decline of P. fluorescens 2P24. Four weeks later, there was little difference between the treatment and control. Generally speaking, the effect of P. fluorescens 2P24 on soil fungal community in cucumber rhizosphere was just transient. PMID:22359632
Functional analysis of OsPGIP1 in rice sheath blight resistance.
Wang, Rui; Lu, Liaoxun; Pan, Xuebiao; Hu, Zongliang; Ling, Fei; Yan, Yan; Liu, Yemao; Lin, Yongjun
As one of the most devastating diseases of rice, sheath blight causes severe rice yield loss. However, little progress has been made in rice breeding for sheath blight resistance. It has been reported that polygalacturonase inhibiting proteins can inhibit the degradation of the plant cell wall by polygalacturonases from pathogens. Here, we prokaryotically expressed and purified OsPGIP1 protein, which was verified by Western blot analysis. Activity assay confirmed the inhibitory activity of OsPGIP1 against the PGase from Rhizoctonia solani. In addition, the location of OsPGIP1 was determined by subcellular localization. Subsequently, we overexpressed OsPGIP1 in Zhonghua 11 (Oryza sativa L. ssp. japonica), and applied PCR and Southern blot analysis to identify the positive T0 transgenic plants with single-copy insertions. Germination assay of the seeds from T1 transgenic plants was carried out to select homozygous OsPGIP1 transgenic lines, and the expression levels of OsPGIP1 in these lines were analyzed by quantitative real-time PCR. Field testing of R. solani inoculation showed that the sheath blight resistance of the transgenic rice was significantly improved. Furthermore, the levels of sheath blight resistance were in accordance with the expression levels of OsPGIP1 in the transgenic lines. Our results reveal the functions of OsPGIP1 and its resistance mechanism to rice sheath blight, which will facilitate rice breeding for sheath blight resistance. PMID:25488398
Chemical composition and antifungal activity of volatiles from three Opuntia species growing in Tunisia.
Bergaoui, Afifa; Boughalleb, Naima; Ben Jannet, Hichem; Harzallah-Shiric, F; El Mahjoub, Mohamed; Mighri, Zine
The chemical composition of the volatiles isolated by steam distillation from leaves, flowers and fruits of Opuntia lindheimeri var. linguiformis L. Benson, leaves and flowers of Opuntia macrorhiza Engelm and leaves of Opuntia microdasys (Lehmann) gathered in the sea cliff of Monastir town (Tunisia), has been studied by GC and GC-MS. Remarkable differences were noted between the composition and the constituent percentage of the different studied organs. The most important compounds found in leaves, flowers and fruits of Opuntia lindheimeri var. linguiformis were tetradecanoic acid (3.15-13.57%), hexadecanoic acid (8.5-17.33%), butyl tetradecanoate (8.05-21.47%) and (E)-3-Butyldiene phthalide (6.92-15.77%). In the flowers volatile extract of Opuntia macrorhiza, the main compound found was Butyl tetradecanoate (21.14%). The volatile extract from Opuntia microdasys leaves was mainly rich in hexadecanoic acid (13.13%), (E)-3-Butyldiene phthalide (21.4%) and butyl tetradecanoate (5.91%). Volatile components extracts were tested against the fungi Alternaria solani, Botrytis cinerea, Fusarium solani f. sp cucurbitae, Fusarium oxysporum f. sp niveum, Pythium ultimum and Rhizoctonia solani. The strongest inhibitory effect of the all volatile extracts was observed against PMID:19070119
Activation of Pathogenesis-related Genes by the Rhizobacterium, Bacillus sp. JS, Which Induces Systemic Resistance in Tobacco Plants
Kim, Ji-Seong; Lee, Jeongeun; Lee, Chan-hui; Woo, Su Young; Kang, Hoduck; Seo, Sang-Gyu; Kim, Sun-Hyung
Plant growth promoting rhizobacteria (PGPR) are known to confer disease resistance to plants. Bacillus sp. JS demonstrated antifungal activities against five fungal pathogens in in vitro assays. To verify whether the volatiles of Bacillus sp. JS confer disease resistance, tobacco leaves pre-treated with the volatiles were damaged by the fungal pathogen, Rhizoctonia solani and oomycete Phytophthora nicotianae. Pre-treated tobacco leaves had smaller lesion than the control plant leaves. In pathogenesis-related (PR) gene expression analysis, volatiles of Bacillus sp. JS caused the up-regulation of PR-2 encoding ?-1,3-glucanase and acidic PR-3 encoding chitinase. Expression of acidic PR-4 encoding chitinase and acidic PR-9 encoding peroxidase increased gradually after exposure of the volatiles to Bacillus sp. JS. Basic PR-14 encoding lipid transfer protein was also increased. However, PR-1 genes, as markers of salicylic acid (SA) induced resistance, were not expressed. These results suggested that the volatiles of Bacillus sp. JS confer disease resistance against fungal and oomycete pathogens through PR genes expression. PMID:26060440
Phytophthora capsici Epidemic Dispersion on Commercial Pepper Fields in Aguascalientes, Mexico
Zapata-Vázquez, Adrián; Sánchez-Sánchez, Mario; del-Río-Robledo, Alicia; Silos-Espino, Héctor; Perales-Segovia, Catarino; Flores-Benítez, Silvia; González-Chavira, Mario Martín; Valera-Montero, Luis Lorenzo
Chili pepper blight observed on pepper farms from north Aguascalientes was monitored for the presence of Phytophthora capsici during 2008–2010. Initially, ELISA tests were directed to plant samples from greenhouses and rustic nurseries, showing an 86% of positive samples. Later, samples of wilted plants from the farms during the first survey were tested with ELISA. The subsequent survey on soil samples included mycelia isolation and PCR amplification of a 560?bp fragment of ITS-specific DNA sequence of P. capsici. Data was analyzed according to four geographical areas defined by coordinates to ease the dispersal assessment. In general, one-third of the samples from surveyed fields contained P. capsici, inferring that this may be the pathogen responsible of the observed wilt. Nevertheless, only five sites from a total of 92 were consistently negative to P. capsici. The presence of this pathogen was detected through ELISA and confirmed through PCR. The other two-thirds of the negative samples may be attributable to Fusarium and Rhizoctonia, both isolated instead of Phytophthora in these areas. Due to these striking results, this information would be of interest for local plant protection committees and farmers to avoid further dispersal of pathogens to new lands. PMID:22629131
Genetic parameters and correlations of collar rot resistance with important biochemical and yield traits in opium poppy (Papaver somniferum L.).
Trivedi, Mala; Tiwari, Rajesh K; Dhawan, Om P
Collar rot, caused by Rhizoctonia solani Kühn, is one of the most severe fungal diseases of opium poppy. In this study, heritability, genetic advance and correlation for 10 agronomic, 1 physiological, 3 biochemical and 1 chemical traits with disease severity index (DSI) for collar rot were assessed in 35 accessions of opium poppy. Most of the economically important characters, like seed and capsule straw yield per plant, oil and protein content of seeds, peroxidase activity in leaves, morphine content of capsule straw and DSI for collar rot showed high heritability as well as genetic advance. Highly significant negative correlation between DSI and seed yield clearly shows that as the disease progresses in plants, seed yield declines, chiefly due to premature death of infected plants as well as low seed and capsule setting in the survived population of susceptible plants. Similarly, a highly significant negative correlation between peroxidase activity and DSI indicated that marker-assisted selection of disease-resistant plants based on high peroxidase activity would be effective and survived susceptible plants could be removed from the population to stop further spread. PMID:16424606
The induction of Ethylene response factor 3 (ERF3) in potato as a result of co-inoculation with Pseudomonas sp. R41805 and Rhizophagus irregularis MUCL 41833 - a possible role in plant defense.
Velivelli, Siva Ls; Lojan, Paul; Cranenbrouck, Sylvie; de Boulois, Hervé Dupré; Suarez, Juan Pablo; Declerck, Stéphane; Franco, Javier; Prestwich, Barbara Doyle
Colonization of plant rhizosphere/roots by beneficial microorganisms (e.g. plant growth promoting rhizobacteria - PGPR, arbuscular mycorrhizal fungi - AMF) confers broad-spectrum resistance to virulent pathogens and is known as induced systemic resistance (ISR) and mycorrhizal-induced resistance (MIR). ISR or MIR, an indirect mechanism for biocontrol, involves complex signaling networks that are regulated by several plant hormones, the most important of which are salicylic acid (SA), jasmonic acid (JA) and ethylene (ET). In the present study, we investigated if inoculation of potato plantlets with an AMF (Rhizophagus irregularis MUCL 41833) and a PGPR (Pseudomonas sp R41805) either alone or in combination, could elicit host defense response genes in the presence or absence of Rhizoctonia Solani EC-1, a major potato pathogen. RT-qPCR revealed the significant expression of ethylene response factor 3 (EFR3) in mycorrhized potato plantlets inoculated with Pseudomonas sp R41805 and also in mycorrhized potato plantlets inoculated with Pseudomonas sp R41805 and challenged with R. solani. The significance of ethylene response factors (ERFs) in pathogen defense has been well documented in the literature. The results of the present study suggest that the dual inoculation of potato with PGPR and AMF may play a part in the activation of plant systemic defense systems via ERF3. PMID:25723847
Responses of beneficial Bacillus amyloliquefaciens SQR9 to different soilborne fungal pathogens through the alteration of antifungal compounds production
Li, Bing; Li, Qing; Xu, Zhihui; Zhang, Nan; Shen, Qirong; Zhang, Ruifu
Bacillus amyloliquefaciens SQR9 exhibited predominantly antagonistic activities against a broad range of soilborne pathogens. The fungi-induced SQR9 extracts possess stronger antifungal activities compared with SQR9 monoculture extracts. To investigate how SQR9 fine-tunes lipopeptides (LPs) and a siderophore bacillibactin production to control different fungal pathogens, LPs and bacillibactin production and transcription of the respective encoding genes in SQR9 were measured and compared with six different soilborne fungal pathogens. SQR9 altered its spectrum of antifungal compounds production responding to different fungal pathogen. Bacillomycin D was the major LP produced when SQR9 was confronted with Fusarium oxysporum. Fengycin contributed to the antagonistic activity against Verticillium dahliae kleb, Fusarium oxysporum, Fusarium solani, and Phytophthora parasitica. Surfactin participated in the antagonistic process against Sclerotinia sclerotiorum, Rhizoctonia solani, and Fusarium solani. Bacillibactin was up-regulated when SQR9 was confronted with all tested fungi. The reduction in antagonistic activities of three LP and bacillibactin deficient mutants of SQR9 when confronted with the six soilborne fungal pathogens provided further evidence of the contribution of LPs and bacillibactin in controlling fungal pathogens. These results provide a new understanding of specific cues in bacteria-fungi interactions and provide insights for agricultural applications. PMID:25484880
Characterization of the bioactive metabolites from a plant growth-promoting rhizobacteria and their exploitation as antimicrobial and plant growth-promoting agents.
George, Emrin; Kumar, S Nishanth; Jacob, Jubi; Bommasani, Bhaskara; Lankalapalli, Ravi S; Morang, P; Kumar, B S Dileep
A plant growth-promoting bacterial strain, PM 105, isolated from a tea plantation soil from the North Eastern region of India was identified as Pseudomonas aeruginosa through classical and 16S ribosomal DNA (rDNA) gene sequencing. Further studies with this strain confirmed broad spectrum antifungal activity against ten human and plant pathogenic fungal pathogens viz. Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus tubingensis, Candida albicans, Colletotrichum gloeosporioides, Fusarium oxysporum, Pencillium expansum, Rhizoctonia solani, Trichophyton rubrum besides growth-promoting property in cowpea (Vigna unguiculata) and pigeon pea (Cajanus cajan). However, no antibacterial property was exhibited by this strain against the four test bacterial pathogens tested in agar overlay method. The crude bioactive metabolites produced by this strain were isolated with three different solvents that exhibited significant antimicrobial and plant growth-promoting activity. Chloroform extract recorded significant antimicrobial and plant growth-promoting activity. Three major compounds viz. 1-hydroxyphenazine, pyocyanin, and phenazine-1-carboxamide were purified and characterized from crude extracts of this strain by various spectral data. The purified compounds recorded prominent antimicrobial activity but failed to establish the plant growth promotion activity in test crop plants under gnotobiotic conditions. Pyocyanin recorded significant antimicrobial activity, and best activity was recorded against T. rubrum (29 mm), followed by P. expansum (28 mm). These results suggest the use of PM 105 as plant growth-promoting agent in crop plants after successful field trials. PMID:25832181
Effects of Bacillus amyloliquefaciens FZB42 on Lettuce Growth and Health under Pathogen Pressure and Its Impact on the Rhizosphere Bacterial Community
Rändler, Manuela; Schmid, Michael; Junge, Helmut; Borriss, Rainer; Hartmann, Anton; Grosch, Rita
The soil-borne pathogen Rhizoctonia solani is responsible for crop losses on a wide range of important crops worldwide. The lack of effective control strategies and the increasing demand for organically grown food has stimulated research on biological control. The aim of the present study was to evaluate the rhizosphere competence of the commercially available inoculant Bacillus amyloliquefaciens FZB42 on lettuce growth and health together with its impact on the indigenous rhizosphere bacterial community in field and pot experiments. Results of both experiments demonstrated that FZB42 is able to effectively colonize the rhizosphere (7.45 to 6.61 Log 10 CFU g?1 root dry mass) within the growth period of lettuce in the field. The disease severity (DS) of bottom rot on lettuce was significantly reduced from severe symptoms with DS category 5 to slight symptom expression with DS category 3 on average through treatment of young plants with FZB42 before and after planting. The 16S rRNA gene based fingerprinting method terminal restriction fragment length polymorphism (T-RFLP) showed that the treatment with FZB42 did not have a major impact on the indigenous rhizosphere bacterial community. However, the bacterial community showed a clear temporal shift. The results also indicated that the pathogen R. solani AG1-IB affects the rhizosphere microbial community after inoculation. Thus, we revealed that the inoculant FZB42 could establish itself successfully in the rhizosphere without showing any durable effect on the rhizosphere bacterial community. PMID:23935892
Biological role of Trichoderma harzianum-derived platelet-activating factor acetylhydrolase (PAF-AH) on stress response and antagonism.
Yu, Chuanjin; Fan, Lili; Wu, Qiong; Fu, Kehe; Gao, Shigang; Wang, Meng; Gao, Jinxin; Li, Yaqian; Chen, Jie
We investigated the properties of platelet-activating factor acetylhydrolase (PAF-AH) derived from Trichoderma harzianum. The enzyme, comprised of 572 amino acids, shares high homology with PAF-AH proteins from T. koningii and other microbial species. The optimum enzymatic activity of PAF-AH occurred at pH 6 in the absence of Ca2+ and it localized in the cytoplasm, and we observed the upregulation of PAF-AH expression in response to carbon starvation and strong heat shock. Furthermore, PAF-AH knockout transformant growth occurred more slowly than wild type cells and over-expression strains grown in SM medium at 37°C and 42°C. In addition, PAF-AH expression significantly increased under a series of maize root induction assay. Eicosanoic acid and ergosterol levels decreased in the PAF-AH knockouts compared to wild type cells, as revealed by GC/MS analysis. We also determined stress responses mediated by PAF-AH were related to proteins HEX1, Cu/Zn superoxide dismutase, and cytochrome c. Finally, PAF-AH exhibited antagonistic activity against Rhizoctonia solani in plate confrontation assays. Our results indicate PAF-AH may play an important role in T. harzianum stress response and antagonism under diverse environmental conditions. PMID:24964161
Microemulsion Formulation of Carbendazim and Its In Vitro Antifungal Activities Evaluation
Leng, Pengfei; Zhang, Zhiming; Li, Qian; Zhao, Maojun; Pan, Guangtang
The fungus Rhizoctonia solani Kuhn is a widespread and destructive plant pathogen with a very broad host range. Although various pathogens, including R. solani, have been traditionally controlled using chemical pesticides, their use faces drawbacks such as environmental pollution, development of pesticide resistance, and other negative effects. Carbendazim is a well-known antifungal agent capable of controlling a broad range of plant diseases, but its use is hampered by its poor aqueous solubility. In this study, we describe an environmentally friendly pharmaceutical microemulsion system using carbendazim as the active ingredient, chloroform and acetic acid as solvents, and the surfactants HSH and 0204 as emulsifiers. This system increased the solubility of carbendazim to 30 g/L. The optimal microemulsion formulation was determined based on a pseudo-ternary phase diagram; its physicochemical characteristics were also tested. The cloud point was greater than 90°C and it was resistant to freezing down to ?18°C, both of which are improvements over the temperature range in which pure carbendazim can be used. This microemulsion meets the standard for pesticide microemulsions and demonstrated better activity against R. solani AG1-IA, relative to an aqueous solution of pure carbendazim (0.2 g/L). The mechanism of activity was reflected in the inhibition of against R. solani AG1-IA including mycelium growth, and sclerotia formation and germination were significantly better than that of 0.2 g/L carbendazim water solution according to the results of t-test done by SPSS 19. PMID:25310219
Antifungal activity of metabolites of the endophytic fungus Trichoderma brevicompactum from garlic.
Shentu, Xuping; Zhan, Xiaohuan; Ma, Zheng; Yu, Xiaoping; Zhang, Chuanxi
The endophytic fungus strain 0248, isolated from garlic, was identified as Trichoderma brevicompactum based on morphological characteristics and the nucleotide sequences of ITS1-5.8S- ITS2 and tef1. The bioactive compound T2 was isolated from the culture extracts of this fungus by bioactivity-guided fractionation and identified as 4?-acetoxy-12,13- epoxy-?(9)-trichothecene (trichodermin) by spectral analysis and mass spectrometry. Trichodermin has a marked inhibitory activity on Rhizoctonia solani, with an EC50 of 0.25 ?g mL(-1). Strong inhibition by trichodermin was also found for Botrytis cinerea, with an EC50 of 2.02 ?g mL(-1). However, a relatively poor inhibitory effect was observed for trichodermin against Colletotrichum lindemuthianum (EC50 = 25.60 ?g mL(-1)). Compared with the positive control Carbendazim, trichodermin showed a strong antifungal activity on the above phytopathogens. There is little known about endophytes from garlic. This paper studied in detail the identification of endophytic T. brevicompactum from garlic and the characterization of its active metabolite trichodermin. PMID:24948941
Characterization of an endophytic whorl-forming Streptomyces from Catharanthus roseus stems producing polyene macrolide antibiotic.
Rakotoniriana, Erick Francisco; Chataigné, Gabrielle; Raoelison, Guy; Rabemanantsoa, Christian; Munaut, Françoise; El Jaziri, Mondher; Urveg-Ratsimamanga, Suzanne; Marchand-Brynaert, Jacqueline; Corbisier, Anne-Marie; Declerck, Stéphane; Quetin-Leclercq, Joëlle
An endophytic whorl-forming Streptomyces sp. designated as TS3RO having antifungal activity against a large number of fungal pathogens, including Sclerotinia sclerotiorum, Rhizoctonia solani, Colletotrichum gloeosporioides, Cryphonectria parasitica, Fusarium oxysporum, Pyrenophora tritici-repentis, Epidermophyton floccosum, and Trichophyton rubrum, was isolated from surface-sterilized Catharanthus roseus stems. Preliminary identification showed that Streptomyces cinnamoneus subsp. sparsus was its closest related species. However, strain TS3RO could readily be distinguished from this species using a combination of phenotypic properties, 16S rDNA sequence similarity, and phylogenetic analyses. Thus, the whorl-forming Streptomyces sp. strain TS3RO is likely a new subspecies within the Streptomyces cinnamoneus group. Direct bioautography on a thin-layer chromatography plate with Cladosporium cucumerinum was conducted throughout the purification steps for bioassay-guided isolation of the active antifungal compounds from the crude extract. Structural elucidation of the isolated bioactive compound was obtained via LC-MS spectrometry, UV-visible spectra, and nuclear magnetic resonance data. It revealed that fungichromin, a known methylpentaene macrolide antibiotic, was the main antifungal component of TS3RO strain, as shown by thin-layer chromatography bioautography. This is the first report of an endophytic whorl-forming Streptomyces isolated from the medically important plant Catharanthus roseus. PMID:22524528
The Elicitation Effect of Pathogenic Fungi on Trichodermin Production by Trichoderma brevicompactum
Shentu, Xu-Ping; Liu, Wei-Ping; Zhan, Xiao-Huan; Yu, Xiao-Ping; Zhang, Chuan-Xi
The effects of six species of phytopathogenic fungi mycelia as elicitors on trichodermin yield by Trichoderma brevicompactum were investigated. Neither nonviable nor viable mycelia of Botrytis cinerea, Alternaria solani, Colletotrichum lindemuthianum, and Thanatephorus cucumeris demonstrated any elicitation on the accumulation of trichodermin. However, the production of trichodermin was increased by the presence of viable/nonviable Rhizoctonia solani and Fusarium oxysporum mycelia. The strongest elicitation effect was found at the presence of nonviable R. solani. At the presence of nonviable R. solani, the maximum yield of trichodermin (144.55?mg/L) was significantly higher than the Control (67.8?mg/L), and the cultivation time to obtain the maximum yield of trichodermin decreased from 72?h to 60?h. No difference of trichodermin accumulation was observed by changing the concentration of nonviable R. solani from 0.1 to 1.6?g/L. It was observed that the optimum time for adding nonviable R. solani is immediately after inoculation. The diameter of T. brevicompactum mycelial globule after 72?h cultivation with nonviable R. solani elicitor was smaller than that of the Control. PMID:24385883
Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10
Weise, Teresa; Kai, Marco; Gummesson, Anja; Troeger, Armin; von Reuß, Stephan; Piepenborn, Silvia; Kosterka, Francine; Sklorz, Martin; Zimmermann, Ralf; Francke, Wittko
Summary Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and fungi. As a first step to study volatile-based bacterial–plant interactions, the emission profile of Xanthomonas c. pv. vesicatoria 85-10 was determined by using GC/MS and PTR–MS techniques. More than 50 compounds were emitted by this species, the majority comprising ketones and methylketones. The structure of the dominant compound, 10-methylundecan-2-one, was assigned on the basis of its analytical data, obtained by GC/MS and verified by comparison of these data with those of a synthetic reference sample. Application of commercially available decan-2-one, undecan-2-one, dodecan-2-one, and the newly synthesized 10-methylundecan-2-one in bi-partite Petri dish bioassays revealed growth promotions in low quantities (0.01 to 10 ?mol), whereas decan-2-one at 100 ?mol caused growth inhibitions of the fungus Rhizoctonia solani. Volatile emission profiles of the bacteria were different for growth on media (nutrient broth) with or without glucose. PMID:22563356
Identification of swainsonine as a probable contributory mycotoxin in moldy forage mycotoxicoses.
Broquist, H P; Mason, P S; Hagler, W M; Harris, T M
When infested with the fungus Rhizoctonia leguminicola, certain forages, e.g., red clover hay, can cause a "slobber syndrome" of varying severity when consumed by ruminants. The causative agent has been presumed to be slaframine [(1S,6S,8aS)-1-acetoxy-6-aminooctahydroindolizine], which is produced by R. leguminicola. In one serious outbreak of the slobber syndrome in horses, the red clover forage involved was carefully examined and found to contain R. leguminicola and slaframine. An identical hay sample is shown here by ion-exchange chromatographic and gas chromatographic-mass spectrometric analysis of appropriate hay extracts to also contain swainsonine [(1S,2R,8R,8aR)-1,2,8-trihydroxyoctahydroindolizine], a potent alpha-mannosidase inhibitor. Swainsonine has previously been isolated from pure cultures of R. leguminicola and from higher plants, namely the Darling pea (Swainsona canescens) and spotted locoweed (Astragalus lentiginosus). Consumption of Darling pea and spotted locoweed by livestock results in a severe neurological condition resembling that observed in hereditary mannosidosis in cattle and humans. Our findings indicate that swainsonine may be viewed as a mycotoxin when present in moldy forages consumed by livestock. The extent to which slaframine and swainsonine mycotoxicosis pose threats to animal husbandry and, indeed, to humans, if these alkaloids were to enter the human food chain, deserves serious consideration. PMID:6435524
Identification of swainsonine as a probable contributory mycotoxin in moldy forage mycotoxicoses.
Broquist, H P; Mason, P S; Hagler, W M; Harris, T M
When infested with the fungus Rhizoctonia leguminicola, certain forages, e.g., red clover hay, can cause a "slobber syndrome" of varying severity when consumed by ruminants. The causative agent has been presumed to be slaframine [(1S,6S,8aS)-1-acetoxy-6-aminooctahydroindolizine], which is produced by R. leguminicola. In one serious outbreak of the slobber syndrome in horses, the red clover forage involved was carefully examined and found to contain R. leguminicola and slaframine. An identical hay sample is shown here by ion-exchange chromatographic and gas chromatographic-mass spectrometric analysis of appropriate hay extracts to also contain swainsonine [(1S,2R,8R,8aR)-1,2,8-trihydroxyoctahydroindolizine], a potent alpha-mannosidase inhibitor. Swainsonine has previously been isolated from pure cultures of R. leguminicola and from higher plants, namely the Darling pea (Swainsona canescens) and spotted locoweed (Astragalus lentiginosus). Consumption of Darling pea and spotted locoweed by livestock results in a severe neurological condition resembling that observed in hereditary mannosidosis in cattle and humans. Our findings indicate that swainsonine may be viewed as a mycotoxin when present in moldy forages consumed by livestock. The extent to which slaframine and swainsonine mycotoxicosis pose threats to animal husbandry and, indeed, to humans, if these alkaloids were to enter the human food chain, deserves serious consideration. PMID:6435524
Saprotrophic competitiveness and biocontrol fitness of a genetically modified strain of the plant-growth-promoting fungus Trichoderma hamatum GD12.
Ryder, Lauren S; Harris, Beverley D; Soanes, Darren M; Kershaw, Michael J; Talbot, Nicholas J; Thornton, Christopher R
Trichoderma species are ubiquitous soil fungi that hold enormous potential for the development of credible alternatives to agrochemicals and synthetic fertilizers in sustainable crop production. In this paper, we show that substantial improvements in plant productivity can be met by genetic modification of a plant-growth-promoting and biocontrol strain of Trichoderma hamatum, but that these improvements are obtained in the absence of disease pressure only. Using a quantitative monoclonal antibody-based ELISA, we show that an N-acetyl-?-d-glucosaminidase-deficient mutant of T. hamatum, generated by insertional mutagenesis of the corresponding gene, has impaired saprotrophic competitiveness during antagonistic interactions with Rhizoctonia solani in soil. Furthermore, its fitness as a biocontrol agent of the pre-emergence damping-off pathogen Sclerotinia sclerotiorum is significantly reduced, and its ability to promote plant growth is constrained by the presence of both pathogens. This work shows that while gains in T. hamatum-mediated plant-growth-promotion can be met through genetic manipulation of a single beneficial trait, such a modification has negative impacts on other aspects of its biology and ecology that contribute to its success as a saprotrophic competitor and antagonist of soil-borne pathogens. The work has important implications for fungal morphogenesis, demonstrating a clear link between hyphal architecture and secretory potential. Furthermore, it highlights the need for a holistic approach to the development of genetically modified Trichoderma strains for use as crop stimulants and biocontrol agents in plant agriculture. PMID:21835878
[Screening, identification, and biocontrol effect of antagonistic bacteria against Phytophthora capsici].
Mei, Xin-lan; Zhao, Qing-yun; Tan, Shi-yong; Xu, Yang-chun; Shen, Biao; Shen, Qi-rong
A total of 98 isolates with antagonistic activity against Phytophthora capsici were isolated from the rhizosphere soil of healthy pepper plants in the fields seriously infected by pepper Phytophthora capsicit, and two strains named as HL-3 and LZ-8 were screened, which had the characteristics of wide-spectrum antagonism and good growth under poor soil condition. The HL-3 and LZ-8 were identified as Paenibacillus polymyxa and Bacillus pumilus, respectively, based on their morphological and biochemical characteristics and 16S rDNA sequences. The two strains could inhibit the mycelium growth of P. capsici, and the inhibitory effect of HL-3 and LZ-8 was 72% and 68%, respectively. The two strains also had antifungal activities toward other plant pathogens such as Verticillium dahliae, Fusarium oxysporum f. sp. cucumerinum, F. oxysporum f. sp. vasinfectum, Rhizoctonia solani, Phtophthora parasitica var. nicotiana, and Ralstonia solanacearum. Pot experiment showed that the biocontrol effects of HL-3 and LZ-8 against P. capsici at the seedling stage of pepper were 72% and 83%, respectively, and both of the strains had significant growth-promoting effect on pepper plants. PMID:21328956
Comparative essential oil composition and antifungal effect of bitter fennel (Foeniculum vulgare ssp. piperitum) fruit oils obtained during different vegetation.
Ozcan, Mehmet Musa; Chalchat, Jean-Claude; Arslan, Derya; Ate?, Ay?e; Unver, Ahmet
The chemical composition of the flower and unripe and ripe fruits from fennel (bitter) (Foeniculum vulgare ssp. piperitum) has been examined by gas chromatography and gas chromatography-mass spectrometry. The main identified components of the flower and unripe and ripe fruit oils were estragole (53.08%, 56.11%, and 61.08%), fenchone (13.53%, 19.18%, and 23.46%), and alpha-phellandrene (5.77%, 3.30%, and 0.72%), respectively. Minor qualitative and major quantitative variations for some compounds of essential oils were determined with respect to the different parts of F. vulgare. The oils exerted varying levels of antifungal effects on the experimental mycelial growth of Alternaria alternata, Fusarium oxysporum, and Rhizoctonia solani. The 40 ppm concentrations of fennel oils showed inhibitory effect against mycelial growth of A. alternaria, whereas 10 ppm levels were ineffective. The analyses show that fennel oils exhibited different degrees of fungistatic activity depending on the doses. PMID:17201644
An endophytic Nodulisporium sp. from Central America producing volatile organic compounds with both biological and fuel potential.
Riyaz-Ul-Hassan, Syed; Strobel, Gary; Geary, Brad; Sears, Joe
A Nodulisporium sp. (Hypoxylon sp.) has been isolated as an endophyte of Thelypteris angustifolia (Broadleaf Leaf Maiden Fern) in a rainforest region of Central America. It has been identified both on the basis of its morphological characteristics and by scanning electron microscopy as well as ITS sequence analysis. The endophyte produces volatile organic compounds (VOCs) that have both fuel (mycodiesel) and use for biological control of plant disease. When grown on potato dextrose agar, the organism uniquely produces a series of ketones, including acetone; 2-pentanone; 3-hexanone, 4-methyl; 3-hexanone, 2,4- dimethyl; 2-hexanone, 4-methyl, and 5-hepten, 2-one and these account for about 25% of the total VOCs. The most abundant identified VOC was 1,8 cineole, which is commonly detected in this group of organisms. Other prominent VOCs produced by this endophyte include 1-butanol, 2- methyl, and phenylethanol alcohol. Moreover, of interest was the presence of cyclohexane, propyl, which is a common ingredient of diesel fuel. Furthermore, the VOCs of this isolate of Nodulisporium sp. were selectively active against a number of plant pathogens, and upon a 24 h exposure caused death to Phytophthora palmivora, Rhizoctonia solani, and Sclerotinia sclerotiorum and 100% inhibition to Phytophthora cinnamomi with only slight to no inhibition of the other pathogens that were tested. From this work, it is becoming increasingly apparent that each isolate of this endophytic Nodulisporium spp., including the Daldina sp. and Hypoxylon spp. teleomorphs, seems to produce its own unique set of VOCs. PMID:23314364
Endophytic and ectophytic potato-associated bacterial communities differ in structure and antagonistic function against plant pathogenic fungi.
Berg, Gabriele; Krechel, Annette; Ditz, Michaela; Sikora, Richard A; Ulrich, Andreas; Hallmann, Johannes
Differences between endophytic and ectophytic bacterial communities with stress on antagonistic bacteria, were studied by comparing the composition of communities isolated from the rhizosphere, phyllosphere, endorhiza and endosphere of field-grown potato plants using a multiphasic approach. Terminal restriction fragment length polymorphism analysis of 16S rDNA of the bacterial communities revealed discrete microenvironment-specific patterns. To measure the antagonistic potential of potato-associated bacteria, a total of 2648 bacteria were screened by dual testing of antagonism to the soilborne pathogens Verticillium dahliae and Rhizoctonia solani. Composition and diversity of bacterial antagonists were mainly specific for each microenvironment. The rhizosphere and endorhiza were the main reservoirs for antagonistic bacteria and showed the highest similarity in their colonisation by antagonists. The most prominent species of all microenvironments was Pseudomonas putida, and rep-PCR with BOX primers showed that these isolates showed microenvironment-specific DNA fingerprints. P. putida isolates from the rhizosphere and endorhiza gave nearly identical fingerprints confirming the high similarity of bacterial populations. The phlD gene, involved in the production of the antibiotic 2,4-diacetyl-phloroglucinol, was found only among Pseudomonas isolates from the rhizosphere and endorhiza. Evaluation of the bacterial isolates for biocontrol potential based on fungal antagonism and physiological characteristics resulted in the selection of five promising isolates from each microenvironment. The most effective isolate was Serratia plymuthica 3Re4-18 isolated from the endorhiza. PMID:16329870
All eight possible mono-beta-D-glucosides of validoxylamine A. I. Preparation and structure determination.
Asano, N; Kameda, Y; Matsui, K
Validamycin A is the major and most active compound among the validamycin complex. Since the site of beta-glucosidic attachment to validoxylamine A (1) was expected to affect the activity against the pathogenic fungus, Rhizoctonia solani, all eight possible mono-beta-D-glucosides of 1 were prepared. 2-O-, 4-O-, 4'-O-, and 7'-O-beta-D-glucopyranosylvalidoxylamine A (2, 4, 6 and 9, respectively) were prepared by microbial beta-glycosylation of 1 with strains of Rhodotorula sp. 7-O- and 6'-O-beta-D-glucopyranosylvalidoxylamine A (5a and 8a, respectively) were prepared semisynthetically through microbial formation of 7-O-beta-D-glucopyranosylvalidamine (10), oxidation of the primary amine of 10 to a ketone, and coupling of the ketone derivative with valienamine, and through microbial formation of 6-O-beta-D-glucopyranosylvalienamine (11), and coupling of 11 with (2R)-(2,4/3,5)-2,3,4-trihydroxy-5-hydroxymethylcyclohexanone (12), respectively. 3-O- and 5'-O-beta-D-glucopyranosylvalidoxylamine A (3a and 7a, respectively) were chemically synthesized. PMID:1778791
Host Growth Can Cause Invasive Spread of Crops by Soilborne Pathogens
Leclerc, Melen; Doré, Thierry; Gilligan, Christopher A.; Lucas, Philippe; Filipe, Joăo A. N.
Invasive soilborne plant pathogens cause substantial damage to crops and natural populations, but our understanding of how to prevent their epidemics or reduce their damage is limited. A key and experimentally-tested concept in the epidemiology of soilborne plant diseases is that of a threshold spacing between hosts below which epidemics (invasive spread) can occur. We extend this paradigm by examining how plant-root growth may alter the conditions for occurrence of soilborne pathogen epidemics in plant populations. We hypothesise that host-root growth can 1) increase the probability of pathogen transmission between neighbouring plants and, consequently, 2) decrease the threshold spacing for epidemics to occur. We predict that, in systems initially below their threshold conditions, root growth can trigger soilborne pathogen epidemics through a switch from non-invasive to invasive behaviour, while in systems above threshold conditions root growth can enhance epidemic development. As an example pathosystem, we studied the fungus Rhizoctonia solani on sugar beet in field experiments. To address hypothesis 1, we recorded infections within inoculum-donor and host-recipient pairs of plants with differing spacing. We translated these observations into the individual-level concept of pathozone, a host-centred form of dispersal kernel. To test hypothesis 2 and our prediction, we used the pathozone to parameterise a stochastic model of pathogen spread in a host population, contrasting scenarios of spread with and without host growth. Our results support our hypotheses and prediction. We suggest that practitioners of agriculture and arboriculture account for root system expansion in order to reduce the risk of soilborne-disease epidemics. We discuss changes in crop design, including increasing plant spacing and using crop mixtures, for boosting crop resilience to invasion and damage by soilborne pathogens. We speculate that the disease-induced root growth observed in some pathosystems could be a pathogen strategy to increase its population through host manipulation. PMID:23667560
Identity, Diversity, and Molecular Phylogeny of the Endophytic Mycobiota in the Roots of Rare Wild Rice (Oryza granulate) from a Nature Reserve in Yunnan, China? †
Yuan, Zhi-lin; Zhang, Chu-long; Lin, Fu-cheng; Kubicek, Christian P.
Rice (Oryza sativa L.) is, on a global scale, one of the most important food crops. Although endophytic fungi and bacteria associated with rice have been investigated, little is known about the endophytic fungi of wild rice (Oryza granulate) in China. Here we studied the root endophytic mycobiota residing in roots of O. granulate by the use of an integrated approach consisting of microscopy, cultivation, ecological indices, and direct PCR. Microscopy confirmed the ubiquitousness of dark septate endophytes (DSEs) and sclerotium-like structures in root tissues. Isolations from 204 root segments from 15 wild rice plants yielded 58 isolates, for which 31 internal transcribed spacer (ITS)-based genotypes were recorded. The best BLAST match indicated that 34.5% of all taxa encountered may represent hitherto undescribed species. Most of the fungi were isolated with a very low frequency. Calculation of ecological indices and estimation of taxon accumulation curves indicated a high diversity of fungal species. A culture-independent approach was also performed to analyze the endophytic fungal community. Three individual clone libraries were constructed. Using a threshold of 90% similarity, 35 potentially different sequences (phylotypes) were found among 186 positive clones. Phylogenetic analysis showed that frequently detected clones were classified as Basidiomycota, and 60.2% of total analyzed clones were affiliated with unknown taxa. Exophiala, Cladophialophora, Harpophora, Periconia macrospinosa, and the Ceratobasidium/Rhizoctonia complex may act as potential DSE groups. A comparison of the fungal communities characterized by the two approaches demonstrated distinctive fungal groups, and only a few taxa overlapped. Our findings indicate a complex and rich endophytic fungal consortium in wild rice roots, thus offering a potential bioresource for establishing a novel model of plant-fungal mutualistic interactions. PMID:20038691
Posttranscriptional Regulation of 2,4-Diacetylphloroglucinol Production by GidA and TrmE in Pseudomonas fluorescens 2P24
Zhang, Wei; Zhao, Zhao; Zhang, Bo; Wu, Xiao-Gang; Ren, Zheng-Guang
Pseudomonas fluorescens 2P24 is a soilborne bacterium that synthesizes and excretes multiple antimicrobial metabolites. The polyketide compound 2,4-diacetylphloroglucinol (2,4-DAPG), synthesized by the phlACBD locus, is its major biocontrol determinant. This study investigated two mutants defective in antagonistic activity against Rhizoctonia solani. Deletion of the gidA (PM701) or trmE (PM702) gene from strain 2P24 completely inhibited the production of 2,4-DAPG and its precursors, monoacetylphloroglucinol (MAPG) and phloroglucinol (PG). The transcription of the phlA gene was not affected, but the translation of the phlA and phlD genes was reduced significantly. Two components of the Gac/Rsm pathway, RsmA and RsmE, were found to be regulated by gidA and trmE, whereas the other components, RsmX, RsmY, and RsmZ, were not. The regulation of 2,4-DAPG production by gidA and trmE, however, was independent of the Gac/Rsm pathway. Both the gidA and trmE mutants were unable to produce PG but could convert PG to MAPG and MAPG to 2,4-DAPG. Overexpression of PhlD in the gidA and trmE mutants could restore the production of PG and 2,4-DAPG. Taken together, these findings suggest that GidA and TrmE are positive regulatory elements that influence the biosynthesis of 2,4-DAPG posttranscriptionally. PMID:24747907