Biological control of potential antagonistic bacteria isolates to restrict Magnaporthe grisea infection on rice

摘要

Rice blast caused by Magnaporthe grisea, frequently affects rice in the world. This research is intended to screen biological control agents for controlling M. grisea, referencing the study biological control agents testing approaches, since biological control is an environmentally friendly plant disease controlling approach. 710 bacterial isolates were discovered from rice tissues, of which hopeful biological control scores were discovered referencing their abilities in antagonism inhibition and secreting extracellular hydrolytic enzyme. Biological control discovery against M. grisea were experimented on 35 bacterial strains with hopeful biological control characteristic examining through amplified ribosomal DNA restriction analysis (ARDRA) and BOX analysis on isolates with high assessment scores. Five biological control agents (BCAs) with protection efficacy of more than 40% in greenhouse and field experiment were discovered. Pantoea ananatis HS-8 and Bacillus cereus DL-7 performed well in greenhouse experiment, and field test respectively. In general, correlation coefficient is 0.95 between assessment scores of 35 experimented BCAs and correlation coefficient between antagonism test and biological control efficacy show 0.72 against M. grisea. Biological control efficacies results in greenhouse and field experiments showed positive correlation with assessment scores, proposing that the BCAs evaluating and screening method set-up is reference for screening BCAs for controlling M. grisea.