Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2002
Publication Date: June 1, 2002
Citation: Press, C.M., Mahaffee, W.F., Roche, M.M., Sechler, T.M., Davis, A.L. Role Of Biofilms In Biocontrol Of Botrytis Cinerea. Interpretive Summary: The ability of biocontrol agents to control disease is dependent on colonization of plant surfaces. This research describes work on understanding the role of biofilm formation (process by which microbes from very large aggregates on surfaces)in the biological control of gray mold of geranium and how this knowledge has been applied to enhance commercail biocontrol agents.
Technical Abstract: Microorganisms often inhabit the leaf surface in organized structures termed biofilms. Burkholderia sp., FP62 is a biocontrol agent of B. cinerea in geranium and forms extensive biofilms in the phyllosphere. Scanning electron micrographs demonstrate extensive phyllosphere colonization (60-70% of the leaf surface). FP62 biofilms appeared to be many cells layers thick and enveloped in a polymer-like matrix. The biofilm phenotype of this strain is related to biocontrol. Isolation of transposon mutants that are deficient in biofilm formation in an in vitro biofilm assay, also lacked the capacity to control B. cinerea when applied to geranium leaves. The biofilm mutants are less efficient in phyllosphere colonization lacking many of the characteristics of wild-type biofilms. The biofilm mutation and biocontrol capacity could be restored through the addition of exogenous polymer to the biocontrol formulation of the mutants. The addition of polymers to the formulation of several other biocontrol agents also improved their biocontrol capacity suggesting that biofilms contribute to biocontrol efficacy and are an important aspect of phyllosphere competance.