오이 노균병의 생물적 방제를 위한 Bacillus amyloliquefaciens CC110균주 선발

Abstract

Pseudoperonospora cubensis에 의한 오이 노균병의 생물적 방제를 위하여 오이 재배단지의 오이 식물체 126균주를 분리하였다. 그 중에서 잎 절편 생물검정 통하여 5균주를 선발하였다. CC110균주는 오이노균병 예방과 치료효과 검정에서 전혀 병이 발생하지 않았지만 무처리는 15.0~18% 노균병이 발생하였다. CC110균주는 gyrB gene sequence 분석에 의하여 Bacillus amyloliquefaciens subsp. plantarum로 동정하였다. CC110균주를 TSB배지에서 배양한 배양액은 LB, NB와 KB 배지에서 배양한 배양액보다 오이 노균병 발생이 적어 효과적이었다. CC110균주를 TSB배지에서 배양한 배양액의 원액, 2배와 5배 희석한 처리구에서 0%, 3.0%와 8.0% 그리고 배양여액을 원액, 2배와 5배 희석한 처리구에서 0%, 4.0%와 7.0% 노균병이 발생하였고, 무처리는 21.0% 발생하였다. 오이 유묘검정에서 CC110균주를 TSB배지에서 배양한 배양액은 오이 노균병이 35.0% 발생하였고 무처리는 82.0% 발생하였다. 비닐하우스 포장에서 오이 노균병에 대하여 B. amyloliquefaciens CC110균주를 5일 간격 4회 처리가 7일 간격 3회 처리보다 방제효과가 높았다. In order to select antagonists for biological control of downy mildew of cucumber, 126 bacteria were isolated from cucumber plants collected from several locations in Korea. Among them, Five isolates were selected as potential biocontrol agents of cucumber downy mildew using a leaf disc bioassay method. In preventive and curative effect tests, the isolate CC110 was found to be effective to control downy mildew on cucumber showing diseased area by 0% whereas that of control was 15.0~18.0%. A bacterium isolate CC110 was identified as Bacillus amyloliquefaciens subsp. plantarum based on phylogenetic analysis using gyrB gene sequence. The culture liquid of isolate CC110 in TSB media were more effective for the control of the disease than those cultured in LB, NB, and KB media in leaf disk bioassay. when undiluted liquid, two-fold, five-fold diluted culture broth, and undiluted liquid, two-fold, five-fold diluted filtrate of isolate CC110 in TSB media were treated, diseased area of cucumber powdery mildew were 0%, 3.0%, 8.0%, 0%, 4.0% and 7.0%, respectively, whereas diseased area in the control was 21.0%. In the cucumber seedling tests, when the culture broth of isolate CC110 in TSB media was treated, diseased area were 35.0%, whereas that of control was 82.0%. When B. amyloliquefaciens CC110 was treated four times at five-day interval in the vinylhouse test, the control effect of cucumber downy mildew was higher than that treated three at seven-day interval.