Cultural Characteristics and Mechanism of Bacillus amyloliquefacien subsp. plantarum CC110 for Biological Control of Cucumber Downy Mildew

An isolate of Bacillus amyloliquefaciens subsp. plantarum CC110 was selected as an effectiveantagonist for biological control of cucumber downy mildew caused by Pseudoperonospora cubensis.Temperature range for growth of CC110 isolate was 7.5~55.0 o C, and its optimal temperature at 36.6 o C. pHrange for growth of CC110 isolate was 4.5~9.5, and its optimal pH at 7.0. In this study, the most effectivesources of carbon and nitrogen for growth of CC110 isolate were fructose and yeast extract, respectively. Thevolatile of CC110 isolate was found to be effective to control downy mildew on cucumber showing nodiseased area whereas that of control was 13.2% using the I plate bioassay. The culture broth and cells ofisolate CC110 cultured in TSB media for 48 hours at 28 o C inhibited occurrence of cucumber downy mildew.The cells and culture broth were transformed into sporangia of P. cubensis by in observation under lightmicroscope and scanning electron microscope. Key words Biological control, Cucumber, Cultivation, Downy mildew, Bacillus amyloliquefaciens subsp.plantarum CC110, Volatile compounds