内生贝莱斯芽胞杆菌生物拮抗活性的研究

The antagonistic activity of an endophytic Bacillus velezensis

目的研究内生菌的生物拮抗活性。方法基于植物贴片法、形态学与分子生物学特征等分离、鉴定内生菌;利用纸片扩散法检测分离株拮抗病原性细菌、植物部分内生菌及耐药性细菌的生物活性。结果分离株HBB5的菌落呈乳白色、黏液性、皱褶状凸起,镜下见革兰阳性、单个或成双或短链状排列杆菌;序列分析显示,HBB5菌的16SrRNA基因序列与GenBank数据库中贝莱斯芽胞杆菌(Bacillus velezensis)同源性为100%,鉴定为B.velezensis HBB5。拮抗试验显示,B.velezensis HBB5抑制Staphylococcus aureus、Enterococcus faecalis、Escherichia coli、Salmonella typhi、Salmonella paratyphi A、Shigella dysenteriae、内生Penicillium HBF3及Klebsiella ornithinolytica B1645-1等菌株生长,其与内生B.subtilis SWB8无明显抑制现象。结论首次从盾叶薯蓣植物中分离出Bacillus velezensis,其显示了广谱的抗病原细菌活性及一定的拮抗耐药菌的能力,可能参与宿主植物疾病的防御。

Objective To study the antagonistic activity of endophytes. Methods Endophytes were isolated with plant section culturing method and identified based on the morphological and molecular characteristics. The method of disc diffusion was used to detect the biological activity of the isolated strains against patho- genic bacteria, endophytes from host, and drug resistant bacteria. Results The colony of strain HBB5 was milky white and mucosal with folded bulges. Under microscope, single or double or short chains of Gram positive bacillus were seen. 16S rRNA gene sequence analysis showed that it had 100% homology with Ba- cillus velezensis in the database of GenBank, and was identified as Bacillus velezensis HBBS. The B. velezensis HBB5 showed inhibitory effect against all the six tested pathogenic bacteria strains （Staphylococcus au- reus, Enterococcus f aecalis , Escherichia coli , Salmonella t yphi , Salmonella parat yphi A and Shigella d ysenteri- ae） and noticeable mutual inhibition against Penicillium HBF3 and Klebsiella ornithinolytica B1645-1 （drug resist- ant bacteria）, with no inhibition against B. subtilis SWBS. Conclusion Bacillus velezensis was isolated from Di- oscorea zingiberensis for the first time, which showed a broad spectrum antibacterial activity and certain ability to resist drug resistant bacteria, and possibly involved in the defense of host plant diseases.