Characterization of an antimicrobial material from a newly isolated Bacillus amyloliquefaciens from mangrove for biocontrol of Capsicum bacterial wilt

Understanding the mechanisms of the antagonistic endophytic bacteria is helpful in controlling plant diseases. An endophytic bacterium, Bg-C31, from mangrove was found to be antagonistic to some fungal and bacterial pathogens of plants and to be effective in the biocontrol of Capsicum bacterial wilt in pot and field trials. Bg-C31 was identified as Bacillus amyloliquefaciens by biochemical and physiological tests as well as sequences of 16S rDNA and the LCI gene. The antimicrobial substance produced by Bg-C31 was identified as a protein, which is resistant to protease k and heat, by ammonium sulfate precipitation and butanol extraction. The antagonistic gene was located in the chromosome by plasmid curing. A 29 kDa fusion protein of the LCI gene was expressed. Antimicrobial activity of the fusion protein to Ralstonia solanacearum was detected on gels in situ, indicating that the LCI gene could potentially be used to produce transgenic plants that are resistant to bacterial infection.