Zhou, H., Department of Microbiology, University of Massachusetts, Amherst, MA 01003, United States
Yao, F., Department of Microbiology, University of Massachusetts, Amherst, MA 01003, United States
Roberts, D.P., Sustainable Agric. Syst. Laboratory, USDA-ARS, Bldg. 001, 10300 Baltimore Ave., Beltsville, MD 20705-2350, United States
Lessie, T.G., Department of Microbiology, University of Massachusetts, Amherst, MA 01003, United States

Burkholderia ambifaria BC-F, a biocontrol strain reported previously to exhibit broad-spectrum antifungal activity, was highly active in formation of N-acyl homoserine lactones (AHLs). We constructed AHL-deficient derivatives of strain BC-F in which the genes specifying AHL synthase (bafI) and AHL-binding transcriptional activator (bafR) were inactivated by allelic exchange. The resulting AHL-deficient mutants had decreased antifungal activity.