Study on Resistance Mechanism of Bio-control Strain Bacillus amyloliquefaciens YH-22 against Tobacco Wilt

Through the analysis of ecological colonization and antimicrobial substances of Bacillus amyloliquefaciens YH-22, the resistance mechanism of YH-22 against bacterial wilt which was caused by Ralstonia solanacearum was preliminarily investigated. The tolerance dosage of YH-22 resistance strain against rifampicin reached 400 μg/mL by resistance induction with rifampicin. The results of pot experiments showed that YH-22 resistance strain firstly colonized on the rhizosphere soil. Then, it intruded into the root and stem successively. The antimicrobial substances in broth could be dissolved by methanol, but not by chloroform and ethyl acetate. They could maintain high stability under the conditions of heat treatment, protease hydrolysis and Ultraviolet. Moreover, they had the character of oil displacement and droplet collapse. In conclusion, strain YH-22 has colonization ability in rhizosphere soil as well as tobacco tissue. The antibacterial components of strain YH-22 may consist of proteins and lipopeptides.