Project Number: 5348-22000-013-07
Project Type: Reimbursable

Start Date: Aug 01, 2007
End Date: Jul 31, 2010

Objective:
This proposal focuses on the ecological fitness and spread of Q8r1-96 (produces 2,4-diacetylphloroglucinol, DAPG) and transgenic derivatives of Q8r1-96 (produce DAPG and phenazine-1-carboxylic acid or other biocontrol traits). Specific objectives are: to monitor strain movement, persistence, rhizosphere colonization and non-target effects of wild-type and transgenic strains in the field; to evaluate the impact of crop cultivar on rhizosphere colonization and the persistence of transgenic strains; to develop a more sensitive method for tracking introduced strains; and to determine the impact on ecological fitness of pyramiding multiple biocontrol genes into a strain.

Approach:
The parental strain Pseudomonas fluorescens Q8r1-96, transgenic strains Z30-97 and Z15-02, and other transgenics with multiple biocontrol genes will be applied individually and in combination to soil or seeds of wheat, pea and other crops. Multiple cultivars of each crop will be used. Treated or non-treated seeds will be sown in the field or in pots of soil in the greenhouse. Roots will be sampled and the population densities of the bacteria will be determined by the PCR-based dilution-endpoint method and by real-time PCR. In the field, population densities of Q8r1-96, Z30-97 and Z15-02 will be monitored in plots previously established and re-sown to wheat or pea. Spread of the bacteria in the fields into non-inoculated plots will continue to be monitored. The impact of wild-type and transgenic strains on the microbial community structure of the rhizosphere will be monitored. Documents Reimbursable with CSREES. Log 33440. Formerly 5348-22000-012-11R (1/08, K.P.)