Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2002
Publication Date: 6/1/2002
Citation: Roche, M.M., Mahaffee, W.F., Press, C.M., Sechler, T.M., Davis, A.L. Characterization Of The Biofilm Phenotype OF Burkholderia SP., FP62 And Its Role In Biocontrol. Interpretive Summary: The ability of biocontrol agents to control disease is dependent on colonization of plant surfaces. This research describes work on understanding the genetics behind biofilm formation (process by which microbes from very large aggregates on surfaces) and its role in the efficacy of the biocontrol agent FP62. Genetic mutant that lost ability to form biofilms on leaf tissue were shown to also lose their ability to control gray mold of geranium.
Technical Abstract: Biofilm formation of Burkholderia sp. (FP62) on plant leaves and its role in the biocontrol of Botrytis cinerea(Bc) was examined on geranium. A library of mini-Tn5 lacZ1 transposon mutants was screened for biofilm formation in a polystyrene microtiter plate assay. Mutants deficient in biofilm formation were identified by the absence of a crystal violet stained biofilm ring normally produced by the wild type. Biofilm mutants were identified and tested for biocontrol efficacy against Bc in a geranium plant assay. Among the biofilm deficient mutants, two (55B1, 62E8) were identified that failed to control Bc in a geranium plant assay despite exhibiting antibiosis to Bc in vitro. Southern analysis indicated a single transposon insertion in each mutant. 55B1 and 62E8 had phenotypic changes in colony morphology and colonization pattern on leaf surfaces (determined by SEM) that are distinct from the wild type and from each other. Biocontrol efficacy of 55E1 was restored using polymers associated with biofilms as spray adjuvants in geranium disease assays. These results suggest that biofilm formation plays a role in biocontrol of Bc by FP62.