Identification of the antifungal substances from Bacillus amyloliquefaciens strain YN-1.

The lipopeptide-like antifungal substances produced by Bacillus amyloliquefaciens strain YN-1 were identified and relative quantified. Four primers designed based on the known lipopeptide genes were used to amplify the corresponding genes from YN-1. The PCR products were cloned and sequenced. The extract from YN-1 fermentation liquid was prepared by the acid precipitation,detected by the plate experiment of antagonism,and analyzed with HPLC-ESI-MS and MALDI-TOF-MS methods. The PCR products with three primer pairs were cloned and sequenced. The BLAST analysis showed that the sfp,fenB,ituA or bamA genes exist in the genome of B. amyloliquefaciens YN-1. The extract from YN-1 fermentation liquid could inhibit the mycelial growth of the pathogen Fusarium oxysporum f.sp. vasinfectum. Nine kinds of lipopeptides C14-Iturin A,C15-Iturin A,C16-Iturin A,C14-Fengycin A,C15-Fengycin A,C16-Fengycin A,C17-Fengycin A,C16-Fengycin B and C17-Fengycin B were identified in the antimicrobial extract by the mass spectrum analysis,from which five substances C16-Iturin A,C14-Fengycin A,C16-Fengycin A,C17-Fengycin A and C17-Fengycin B were the major components. Study on B. amyloliquefaciens YN-1 provided a foundation for the development of the micro-fungicide.