REU:  Chemotaxis in Soil Rhizosphere and Symbiotic Infection
{'Code': '08010207', 'Directorate': {'LongName': 'Direct For Biological Sciences'}, 'Division': {'LongName': 'Division Of Environmental Biology'}}
{'SignBlockName': 'Gregory J. McCants'}
Chemotaxis is the process by which bacteria detect important               nutrients, poisons and other substances and move toward or away                 from their source by swimming.  The molecular, cellular and                     genetic mechanisms involved in chemotaxis have been studied                     extensively in a few bacteria such as E. coli.  However, there                  has been virtually no work done to determine how chemotaxis                     contributes to the survival and competitive success of bacterial                species in natural environments.  Chemotaxis is a very                          sophisticated behavioral response.  It requires both the co-                    ordination and functioning of over 60 genes and the expenditure                 of a significant fraction of the cell's energy resources.  So it                seems likely that chemotaxis and its regulation are major                       determinants of lifestyle and competitive success for many                      bacteria.                                                                            The proposed studies will explore the role of chemotaxis in                the ecological success of a particular soil bacterium,                          Bradyrhizobium japonicum.  B. japonicum is an agronomically                     important symbiont of soybean.  It stimulates the formation of                  nodules in which the bacterium converts nitrogen from the air                   into ammonia for the plant in symbiotic exchange for carbon fixed               by the plant through photosynthesis.  Formation of nodules                      depends on the ability of the bacterium to survive in the soil in               the absence of its host, its ability to detect, reach and                       colonize the root surface of its host, and its ability to get to                those few root cells on the surface that are developmentally                    susceptible to infection.                                                            The contribution of chemotaxis to each of these steps will                 be investigated.  Previous studies have shown that bacterial                    mutants which have defective chemotaxis are significantly less                  efficient in nodule formation.  Conversely, mutants with                        enhanced chemotaxis are more efficient nodulators.  Mutations in                several of the genes required for nodule formation specifically                 abolish some chemotactic responses.  In further studies, mutants                of B. japonicum with enhanced, altered or disfunctional                         chemotaxis will be isolated, characterized and compared in                      mixtures with the parental strain to determine which aspects of                 chemotaxis contribute importantly to soil survival, root                        colonization and symbiotic infection.  Long range goals are to                  understand how chemotaxis contributes to success in dealing with                the demands of complex, dynamic environments and to use this                    knowledge to enhance the symbiotic performance of plant-                        associated bacteria.
{'FirstName': 'Wolfgang', 'LastName': 'Bauer', 'EmailAddress': 'bauer.7@osu.edu', 'StartDate': '05/01/1989', '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': '1127', 'Text': 'EVOLUTIONARY PROCESSES CLUSTER'}, {'Code': '9145', 'Text': 'SPECIAL PROGRAMS-RESERVE'}]
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