甜菜内生真菌分离鉴定与抗菌活性研究

Isolation,Identification and Antibacterial Activity of Endophytic Fungi from Beta vulgaris L.

植物内生真菌一直是药物先导化合物的优质来源。甜菜作为我国主要糖料作物,对其内生真菌种类和代谢产物的研究却较少。本研究通过对甜菜内生真菌进行分离鉴定与抗菌活性研究,旨在丰富甜菜内生真菌资源,并为进一步开发利用提供依据。本研究通过组织分离法获得甜菜内生真菌19株,经形态学和ITS序列鉴定为6个种,用2种培养基对其进行发酵,产物用乙酸乙酯进行提取,以金黄色葡萄球菌、藤黄微球菌、枯草芽孢杆菌、大肠杆菌作为指示菌,进行活性测试。通过液相色谱、核磁共振和质谱对化合物进行分离和结构确定。6种甜菜内生真菌中,能够对大肠杆菌产生抗性的菌株有3种,能够对金黄色葡萄球菌、藤黄微球菌和枯草芽孢杆菌产生抗性的菌株有5种。从内生真菌Alternaria alternate发酵产物中分离得到3个化合物。结果表明甜菜内生真菌资源有很大的开发利用空间,部分菌种抑菌活性显著,值得进一步研究。

Endophytic fungi in plants have always been an excellent source of drug lead-compounds.Although sugar beet is the main sugar crop in China,there are few studies on its fungi and metabolites.By isolating and identifying endophytic fungi in sugar beet and studying antibacterial activity,this study aims to enrich the resources of endophytic fungi in sugar beet and provide a reference for further development and utilization.In this study,a total of 19 strains were obtained by tissue separation method.According to morphology and ITS sequence,they were identified as six specie.They were further fermented with two kinds of culture medium,and extracted by ethyl acetate.Staphylococcus aureus,Micrococcus lutea,Bacillus subtilis and Escherichia coli were used as indicators to test the activity.The compounds were separated by liquid chromatography and their structures were determined by NMR and MS.Of the six endophytic fungi,three strains had antibacterial activity against Escherichia coli,while five strains exhibited activity against Staphylococcus aureus,Micrococcus luteus and Bacillus subtilis.Three compounds were separated from the fermentation products of endophytic fungus Alternaria alternate.The results show that there is great potential for development and utilization of endophytic fungi resources in Beta vulgaris L.,and some strains perform significant antibacterial activity,and are worthy of further study.