Molecular Genetics of Extracellular Polysaccharide          Synthesis in Erwinia Stewartii
{'Code': '08070100', 'Directorate': {'LongName': 'Direct For Biological Sciences'}, 'Division': {'LongName': 'Div Of Molecular and Cellular Bioscience'}}
{'SignBlockName': 'Philip Harriman'}
Erwinia stewartii causes both a leaf blight and vascular wilt                   of field and sweet corn.  The long term goal of our research is                 to understand how E. stewartii damages plants.  The primary                     mechanism of pathogenicity of this bacterium is production of                   extracellular polysaccharide (EPS) that occludes the xylem                      vessels and causes the plant to wilt.  When the bacterium grows                 in the intercellular spaces of young leaves, it produces a                      symptom called "watersoaking" (Wts) that is due to the loss of                  cell membrane semipermeability and the resulting accumulation                   of fluids in the tissue.  The cause of Wts is not known but                     recent genetic evidence from our lab suggests that a                            polysaccharide may be involved.  We have discovered a large                     region of the E. stewartii chromosome that is involved in                       synthesis of EPS (cpsA-D) and have also identified a positive                   regulatory gene, rcsA, that is required for expression of the                   cps locus.  Mutations in cpsC-D and rcsA both result in loss of                 Wts ability.                                                                                                                                                    Since polysaccharide synthesis and overall pathogenicity in E.                  stewartii appear to be coordinately regulated by rcsA, we are                   proposing to study the regulation of EPS synthesis and the                      organization of cps genes in this bacterium as a model of                       pathogenicity gene expression.  Specific objectives are: l) Use                 cps::lac gene fusions to determine external signals such as                     nutrition and temperature that affect regulation of EPS                         synthesis.  2) Characterize genes that regulate transcription                   of cps operons.  3) Compare the nucleotide sequence of rcsA                     genes from E. stewartii and E. coli.  4) Determine if EPS                       synthesis is regulated by lon proteolysis of the RcsA protein.                  5) Continue genetic analysis of the cps gene cluster.
{'FirstName': 'David', 'LastName': 'Coplin', 'EmailAddress': None, 'StartDate': '10/01/1987', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'Ohio State University Research Foundation -DO NOT USE', 'CityName': 'Columbus', 'ZipCode': '432101016', 'PhoneNumber': '6146888734', 'StreetAddress': '1960 KENNY RD', 'CountryName': 'United States', 'StateName': 'Ohio', 'StateCode': 'OH'}
[{'Code': '1112', 'Text': 'Genetic Mechanisms'}, {'Code': '9120', 'Text': 'CROSS-DIRECTORATE PROGRAMS'}]
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1987&All=true', 'xml': '8703722.xml'}