Identification of the Lipopeptides from Bacillus amyloliquefaciens Lx-11 and Biocontrol Efficacy of Surfactin Against Bacterial Leaf Streak

【Objective】The objective of this study is to isolate and identify the lipopeptides produced by Bacillus amyloliquefaciens Lx-11 and their biocontrol efficacy against bacterial leaf streak(BLS).【Method】 Three primers designed based on the known lipopeptide genes were used to amplify the corresponding genes from the genome of Lx-11 strain.Lipopeptides were identified by MALDI-TOF-MS techniques.【Result】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 Lx-11.Three kinds of lipopeptides surfactin,bacillomycin D and fengycin were identified in the antimicrobial extract by the mass spectrum analysis.The antibacterial activity could be associated with surfactin-lipopeptides,and practically abolished in surfactin-deficient mutants.Lx-11 strain significantly reduced disease incidence of BLS.【Conclusion】The antibacterial activity of the surfactin-deficient mutant strain was practically abolished,which suggested that surfactin might play an important role in control of BLS.