川蔓藻内生及根际细菌多样性与抑菌活性研究

该研究采用稀释涂布法结合形态观察、16S rRNA基因序列分析,对广西北海川蔓藻(Ruppia maritima)内生及根际细菌的物种多样性进行了研究,并采用琼脂扩散法和光度计法分析了其粗提物抑制马尔尼菲青霉菌活性。结果表明:从川蔓藻中分离到可培养内生细菌26株,根际可培养细菌31株。分别将内生细菌归属为10科12属13种,根际分离出细菌归属为9科14属19种,其中5株根际细菌可能为潜在新种。获得8株细菌对马尔尼菲青霉菌有抑制活性,总阳性率为25.0%。其中,菌株BGMRC 2015、BGMRC 2059、BGMRC 2043的粗提物表现出较强的抑制马尔尼菲青霉菌效果,其MIC分别为(1.800±0.045)、(1.881±0.061)、(1.604±0.021)mg·m L~(-1)。川蔓藻中可培养细菌具有较高的物种多样性,蕴藏着丰富的新物种资源,且富含抑菌活性良好的菌株。

Diversity and antifungal activity of endophytic and rhizospheric bacteria isolated from Ruppia maritima

The purpose of this study was to investigate the diversity of endophytic and rhizospheric bacteria of Ruppia maritima collected from Beihai City and antifungal activities against Penicilliosis marneffei. The endophytic and rhizosphere bacteria isolated from Ruppia maritima were analyzed by method of dilution butteron on plate. 16S rRNA gene sequencing was employed to explore species diversities and the effects of the crude extract from bacteria against Penicilliosis marneffei with agar diffusion method and spectrophotometer method. Total of 26 strains of endophytic bacteria and 31 strains of rhizosphere bacteria were isolated from Ruppia maritina. Thirteen species of endophytic bacteria were obtained and classified into twelve genera and ten families. Nineteen species of bacteria were isolated from rhizosphere and belonging to fourteen generas and nine families. And five strains in the rhizosphere were potential new genera. Crude extracts of eight strains showed inhibition effect against Penicilliosis marneffei, three of which had strong antifungal activities, and their MIC₅₀ were(1.800 ± 0.045),(1.881 ± 0.061)and(1.604 ± 0.021)mg·mL^-1. Endophytic and rhizospheric bacteria of Ruppia maritima are genetically diverse and most of them showed strong inhibition effects against Penicilliosis marneffei.