Abstract: In order to provide a safe, efficient and easy way of biological control against Botrytis cinerea, Bacillus strains with inhibitory activity were screened and the activity and stability of its extracellular antimicrobial components were determined. The research provided scientific basis for the research and development of biocontrol agents. 4 200 strains of Bacillus spp. were isolated by dilution plate method from 129 soil samples of vegetable planting soil from Yunnan, Heilongjiang, Xinjiang and Hebei Province. 191 strains with antagonistic ability against Botrytis cinerea were obtained by dural culture method. Among them, strain KA4 had the strongest inhibition ability and the inhibition rate against Botrytis cinerea was 65.34%. The strain KA4 was identified as Bacillus amyloliquefaciens and named BA-KA4 by morphological, physiological and biochemical characteristics, 16S rDNA and gyrB gene sequence analysis. The sterile fermentation broth of this strain had strong antimicrobial activity. The inhibition rates of BA-KA4 sterile fermentation broth with 10-fold, 20-fold and 40-fold dilution were 78.83%, 65.19%, 45.38%,respectively. The single factor method was used to determine the effect of different treatment temperature, pH value and UV irradiation time on the antibacterial activity of BA-KA4 sterile fermentation broth. The sterile fermentation broth of this strain had good temperature, pH and UV stability. Comprehensively, B. amyloliquefaciens BA-KA4 could inhibit the growth of Botrytis cinerea and the activity of extracellular antimicrobial substances was stable,which could be used as a good microbial resource for biological control of Botrytis cinerea and had a good development prospect.

Key words: Gray mould, Botrytis cinerea, Bacillus amyloliquefaciens, Biocontrol, Extracellular bacteriostatic components

CLC Number: 

• S434.4