Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2011
Publication Date: June 1, 2011
Citation: Zhang, J., Thomashow, L.S., Mavrodi, O.V., Mavrodi, D.V., Weller, D.M. 2011. Construction of recombinant fluorescent Pseudomonas spp. for suppression of soilborne pathogens. Phytopathology. 101:S201. Technical Abstract: Take-all, caused by Gaeumannomyces graminis var. tritici, and Rhizoctonia root rot, caused by R. solani AG-8, are among the most important soilborne diseases of wheat in the Pacific Northwest. Because of the lack of resistance to these and many other soilborne diseases, wheat roots rely on antagonistic rhizosphere microorganisms as a first line of defense against these diseases. Many of these antagonists lack activity against a wide range of pathogens. The purpose of this study was to construct recombinant fluorescent Pseudomonas spp. that produce multiple antibiotics and to determine their activity against soilborne pathogens. We stably inserted the biosynthesis loci for several different antibiotics into various biocontrol strains of P. fluorescens. All recombinant strains produced both their indigenous antibiotic and that encoded by the introduced genes, but the level of antibiotic production varied significantly depending on the transgenes introduced and the recipient P. fluorescens strain. In general, recombinant strains inhibited target pathogens better that did the respective wild-type strain, but inhibition varied by strain. Our results indicate the need to carefully screen strains and antibiotic combinations to obtain recombinants that retain the traits of the parental strain and exhibit broader activity due to the transgenes.