Screening and Activity Evaluation of Four Kinds of Biocontrol Bacteria Against Rice Blast

In order to find out the growth inhibition effect of biocontrol bacteria on Magnaporthe oryzae,four kinds of strains of biocontrol bacteria such as Bacillus amyloliquefaciens D1,Stenotrophomonas maltophilia he41,Lysinibacillus fusiformis he14,Bacillus subtilis H3 which had obvious inhibitory effects on M. oryzae were screened out from the tested strains via the plate-screening method and the growth rate method. The growth rate method was used to determine the inhibitory effect of four biocontrol bacteria on M.oryzae,and the genetic stability,high temperature resistance,UV resistance and acid and alkali resistance of the biocontrol activities of the four strains were studied. The results showed that,the inhibitory rate of M.oryzae was between 13.19% and 100% when the sterile fermentation filtrates of stains was between 0.5% and 64%. The antibacterial activity of strains D1,he41,he14 and H3 was over 86% after cultured for 30 times,inhibitory rate of he14 stain fermentation broth was 82% after treatment with 121 ℃,and the fermentation broth of stains D1,he41 and H3 after treatment with 40 ℃ had no inhibition on M. oryzae. The inhibitory rates of D1,he41,he14 and H3 stains fermentation broth were over 83% after exposure for 6 h under UV lamp(30 W),and the inhibitory rate of D1,he41,he14 and H3 stains fermentation broth was more than 82% after treatment with pH3~11.Above all,strain he14 was a potential strain with a centain biocontrol effect against rice blas,which laid the foundation for the development of microbial preparation for controlling rice blast.