黑水虻肠道细菌抗菌筛选及其活性物质分子鉴定

【目的】从昆虫黑水虻分离的肠道细菌进行抗植物病原菌的拮抗菌筛选,对获得有拮抗活性的肠道细菌进行活性物质的分子鉴定。【方法】用稀释涂布法从水虻肠道中分离菌株,采用平板对峙法进行抗菌筛选,对有抗菌活性的菌株通过生理生化实验、16S rRNA鉴定和进化树分析确定其种属。参考已知脂肽合成关键基因设计引物,以拮抗菌总DNA为模板进行PCR扩增,对目的片段进行测序。【结果】通过抗菌筛选获得一株对水稻黄单胞菌以及小麦纹枯病病原菌等有很强抑制效果的水虻肠道细菌BSF-CL,经鉴定为枯草芽胞杆菌。脂肽合成关键基因PCR结果显示BSF-CL菌株具有脂肽Iturin和Surfactin合成的关键基因。推测BSF-CL很可能合成脂肽Iturin和Surfactin。【结论】从水虻肠道中分离出对水稻黄单胞菌有很强抑菌活性的菌株,分离菌被鉴定为一种枯草芽胞杆菌,通过活性物质的分子克隆鉴定初步推测其活性物质可能为脂肽Iturin和Surfactin。

Screening of antagonistic bacteria from gut of black soldier fly and the molecular identification of antimicrobial active substances

[Objective] The bacteria from gut of black soldier fly were screened gainst plant pathogenic bacteria, Molecular method was used to identify the active substances from the antagonist bacteria. [Methods] Eleven strains have been isolated with diluted coating method from the gut of black solider fly. The antagonistic strains were screened using the plate confrontation method. The species was identified through the physiological, biochemical experiments and 16S rRNA phylogenetic analysis. Primers of key genes of known lipopeptide, synthesis were designed and purpose fragements were amplified by PCR and sequenceing. [Results] A gut bacteria, named BSF-CL, was obtained with strong inhibitory effect to Xanthomonas oryzae PXo99 and Rhizoctonia solani AG-8, and identified as Bacillus subtilis. The result of PCR showed that strain BSF-CL possibly has the key genes which synthesis lipopeptide Iturin and Surfactin. We speculate that strain BSF-CL can synthesize lipopeptide iturin and surfactin. [Conclusion] A strong active Bacillus subtilis strain BSF-CL against bacterial and fungal pathogen was screened from the gut of black soldier fly. We preliminary speculated that the active substance may be lipopeptide iturin and surfactin through the molecular cloning and identification.