Selection of Bacillus amyloliquefaciens CC110 for Biological Control of Cucumber Downy Mildew Caused by Pseudoperonospora cubensis

Abstract

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.

Isolation of Bacillus aryabhattai GW320 from the Cucumber Rhizospheric Soil and Evaluation of Plant Growth Promoting Activity

“…특히 염류집적이 많은 시설하우스에 미생물이 많이 이용되고 있다. 아직까지 오이 의 생장 촉진을 위한 다양한 농업 유용 활성을 가진 PGPR의 효과에 대한 정보는 거의 없으며, 오이 발생하는 노균병, 흰가루병 및 잿빛곰팡이병에 대한 미생물방제 효과를 검정하는 연구가 대부분이다 (Nam et al, 2010;Lee et al, 2010;Kim et al, 2011;Lee et al, 2013)…”