Microbial inoculants, in particular fluorescent pseudomonads, have been used to control a variety of plant pathogens, both bacterial and fungal. Currently there is a strong impetus to promote research and commercialize these biological control agents due to increased environmental and health concerns over synthetic pesticide use. However, while scientific interest and effort in microbial pesticides is considerable, there remain many limitations for their use and effectiveness. Some of these limitations are the difficulty of use over a diversity of crops and limited knowledge of spatial and temporal distribution of a root system with respect both to colonization and expression of antifungal compounds. This proposal is directed towards defining the range of hosts supporting the production of an antifungal compound, oomycin A, expressed by Pseudomonas fluorescens strain Hv37a and toward identifying the effect of constitutive expression of the antifungal compound over that host range. This proposal is also intended to determine the timing, the site(s), and the influence of wounding of roots on expression of oomycin A of a selected host. This information will be used to help identify opportunities for generic modification of the regulation of antifungal compound(s) for controlling specific types of pathogens of those hosts. %%% The long range goal of this work is the development of consistently effective microbial pesticides for protection against soilborn plant pathogens as a less toxic alternative to synthetic pesticides.
