The goal of this proposal is to evaluate a variety of liquid and solid formulations for commercialization of the wild type and genetically modified strains Pseudomonas fluorescens BL915. Target pests include Rhizocotonia, Pythium, Fusarium, Helminthosporium and Thielaviopsis. Production of pyrrolnitrin and several other antifungal metabolites was increased in the modified strain through gene dosage effects and inactivation of a global repressor system controlling the expression of all antifungal metabolites. The modified strain produces about 10 times the amount of pyrrolnitrin and increased levels of all other known antifungal metabolites produced by the wild type. The best modified strain gives better and more consistent control at lower cell inputs compared to the wild type. Because a good commercial formulation does not exist, diverse types of solid and liquid formulations will be tested by AgraSoL and outside collaborators, often using their proprietary technology. Solid formulations will evaluate stabilizers and additives. The formulations will be monitored for 6 months for cell viability, metabolite stability and biocontrol activity. The best formulations will be selected for continual monitoring and additional experiments will be designed to test and optimize the best formulations.
Anticipated Results/Potential Commercial Applications of Research: Commercialization of strain BL915 is limited by the lack of stable liquid and solid formulations. The choice depends on the crop and the agricultural practice. Formulations must be inexpensive and preserve biocontrol activity for 18 months at room temperature. This will permit sale of carryover product for the next growing season. Primary markets for BL915 include control of damping-off in greenhouse grown vegetables and ornamentals, field crops (particularly cotton), brown patch in turf and a variety of post harvest fungi for citrus. Knowledge gained from these studies is expected to be generally applicable to formulation of other Gram negative bacteria.
