오이 노균병의 생물적 방제를 위하여 Bacillus amyloliquefaciens subsp. plantarum CC110균주를 선발하였다. CC110 균주는 $7.5{sim}55.0^{circ}C$에서 생육 가능하며 최적 온도가 $36.6^{circ}C$이고, pH 4.5~9.5범위에서 생육 가능하고 최적 pH는 7.0이었다. CC110 균주가 가장 잘 이용한 탄소원과 질소원은 fructose와 yeast extract이었다. I 플레이트를 이용한 생물검정에서 CC110 균주가 생성한 휘발성 물질에 의하여 오이 노균병이 발생하지 않았고, 무처리에서 13.2% 발생하였다. CC110 균주를 TSB배지에서 배양한 배양액과 배양세포(cell)를 처리하여 실체현미경, 광학현미경과 주사전자현미경으로 관찰한 결과, 전혀 오이 노균병이 발생하지 않았으며 오이 노균병균의 포자낭 형태가 변형되었다.
An isolate of Bacillus amyloliquefaciens subsp. plantarum CC110 was selected as an effective antagonist for biological control of cucumber downy mildew caused by Pseudoperonospora cubensis. Temperature range for growth of CC110 isolate was $7.5{sim}55.0^{circ}C$, and its optimal temperature at $36.6^{circ}C$. pH range for growth of CC110 isolate was 4.5~9.5, and its optimal pH at 7.0. In this study, the most effective sources of carbon and nitrogen for growth of CC110 isolate were fructose and yeast extract, respectively. The volatile of CC110 isolate was found to be effective to control downy mildew on cucumber showing no diseased area whereas that of control was 13.2% using the I plate bioassay. The culture broth and cells of isolate CC110 cultured in TSB media for 48 hours at $28^{circ}C$ inhibited occurrence of cucumber downy mildew. The cells and culture broth were transformed into sporangia of P. cubensis by in observation under light microscope and scanning electron microscope.
