{'fraction_non_alphanumeric': 0.03875968992248062, 'fraction_numerical': 0.03899459713413202, 'mean_word_length': 4.840877914951989, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
First Report of Fusarium Wilt in Banana Caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 in India

India is the largest producer of the bananas in the world with an annual production of 29.72 million tonnes (FAO, 2014). About 70% of the production is of the Cavendish cultivar Grand Naine (AAA). Recently, the area under the Grand Naine cultivar increased significantly in the state of Uttar Pradesh, India. In June 2017, symptoms of fusarium wilt of banana were observed in a block of Grand Naine in the Faizabad district in Uttar Pradesh (26o46.379'N and 81o59.987'E). The affected plants exhibited distinct yellowing symptoms of mature leaves progressing towards the younger leaves. The lamina of the emerging leaves were markedly reduced and shriveled. The leaves collapsed gradually bending at the petiole (Fig. 1 A, B). The pseudostem showed longitudinal splitting at the base with distinct vascular discoloration (reddish brown, Fig. 1 C, D and E). By September 2017 approximately 42 ha were observed to be affected by the disease. Further survey, confirmed symptoms of the disease in the regions of Kushi Nagar (26o73.988'N and 83o88.697'E) and Ambedkar Nagar (27o10.120'N and 81o31.12'E). Infected vascular strands collected from pseudostem tissues with vascular discoloration were subjected to morphological, molecular and Vertical Compatibility Groups (VCG's) identification. The infected strands were surface sterilized and plated on ¼ strength Potato Dextrose Agar (PDA) medium with 0.5 % streptomycin sulfate (streptomycin sulfate1.2 mL / 240 mL of PDA), an antibacterial agent. White hairy cottony colonies with aerial mycelium producing abundant microconidia were developed after 48 hrs of inoculation that phenotypically resembled Fusarium oxysporum (Leslie and Summerell 2006). It was characterized mainly by non-septate microconidia formed in false heads on short monophialide (Fig. 1F) and chlamydospores with a smooth or rough wall. Molecular confirmation by PCR (Fig. 2A) was made using primers FocTR4-F 5´-CACGTTTAAGGTGCCATGAGAG-3 and FocTR4-R 5′-GCCAGGACTGCCTCGTGA-3′ (Dita et al. 2010), which are specific for F. oxysporum f. sp. cubense Tropical Race 4 (Foc TR-4). An amplification product of 463 bp specific for VCG 01213 (Foc TR4) was obtained which on sequencing (MG458303) confirmed the identity as TR-4. VCG testing (Puhalla 1985) established that the fungal isolates obtained from isolated samples were compatible with VCG 01213/16 confirming the presence of TR-4 in India (Fig. 2B). In continuation the isolates (CSR-F-1 and CSR-F-2) used for confirmation were analyzed for pathogenicity to fulfill Koch's postulates on 50 day old healthy tissue culture plantlets of Grand Naine under polyhouse conditions.. Inoculum production, inoculation and molecular diagnosis was analyzed according to the standardized protocol (Dita et al. 2010) The wounded roots of the plantlets were dipped for 30 min. in 106 spores/ml PDB culture broth and plants were then planted in pots of 3 kg soil capacity with sand media under 28oC (70 % humidity). We used five plants with three replicates of the two isolates with five plants in each replicate in the study. Five pots plants treated with water and five plants treated with Fusarium oxysporum f.sp. lycopersici were also used in the study as control.. After 45 days of incubation both isolates caused typical wilting (Fig. 3B) and internal discoloration symptoms (Fig. 3C & 3D) of Fusarium wilt. The Foc was re-isolated from the infected plants on ¼ strength of PDA medium. All the symptomatic plants inoculated with Foc TR4 showed amplification of the diagnostic amplicon 463bp in PCR analysis, confirming that Foc TR-4 /VCG 01213/16 was causal agent, while the control sets remained asymptomatic. The entire experiment for pathogenicity confirmation from inoculation to the PCR amplification was repeated twice during July 2017 to October 2017 with an interval of 45 days / experiment, to validate the results. The isolates were processed and submitted to ICAR-National Bureau for Agriculturally Important Micro-organism, Mau, India (Authorized national repository). To our knowledge, this is the first report of the presence of Fusarium oxysporum f.sp. cubense TR-4 in India.