一株白及内生细菌的分离鉴定及抑菌机理初步研究

Isolation and identification of an endophytic bacterium from Bletilla striata and preliminary study of antibacterial mechanism

从药用植物白及中分离内生细菌,采用滤纸片扩散法进行抗菌活性筛选,最终得到能够对4种致病菌(金黄色葡萄球菌、大肠杆菌、藤黄微球菌、胡萝卜果胶杆菌)有不同抑制作用的内生细菌BSR2010;采用3种有机溶液(乙酸乙酯、石油醚、正丁醇)对该菌株的发酵产物进行萃取并检测其抑菌活性,发现抑菌活性最强的为乙酸乙酯提取物;根据内生细菌BSR2010的16S rDNA分析结果,将其鉴定为假单胞菌(Pseudomonas sp.);另外,基因检测结果显示BSR2010菌株基因组中具有2,4-二乙酰基藤黄酚(2,4-diacetyl phloroglucinol,DAPG)抑菌活性物质合成的关键基因phlD.

Endophytic bacteria were isolated from Bletilla striata.The filter paper diffusion method was performed to screen endophytic bacteria with antibacterial activities,and an endophytic bacterium(numbered as BSR2010)was obtained,which exhibited different antibacterial activities against four pathogenic bacteria strains,including Staphylococcus aureus,Escherichia coli,Micrococcus luteus,and Pectobacterium carolovorum.Three organic solutions(ethyl acetate,mineral-ether,n-butanol)were used to extract the fermentation product of the strain BSR2010,respectively,and the antibacterial activity of the extracts was tested,and the ethyl acetate extract exhibited the strongest antibacterial activity among them.Subsequently,the strain BSR2010 was identified as Pseudomonas sp.according to its 16S rDNA sequence analysis.Additionally,the detection results of biosynthesis genes related to antimicrobial metabolite showed that the genome of BSR2010 contained phlD.