剑叶龙血树内生真菌的分离及体外抑菌活性筛选

Isolation of endophytic fungi from Dracaena cochinchinensis and their antimicrobial activities

关键词:  剑叶龙血树, 内生真菌, 分离, 抗菌活性, 真菌鉴定

Key words:  Dracaena cochinchinensis, endophytic fungi, isolation, antimicrobial activities, fungal identification

摘要:

为研究剑叶龙血树内生真菌资源多样性,初步探讨和筛选具有抑菌活性的特异性菌株以及进一步开发剑叶龙血树内生真菌的抗菌活性化合物。该文采用植物组织分离法从剑叶龙血树茎和叶中分离内生真菌,对内生真菌进行液体发酵7 d,经乙酸乙酯萃取后制得粗提物,并采用牛津杯扩散法,以10种常见病原菌和5种临床耐药菌为靶标检测其发酵粗提物的抑菌活性,对有较好抑菌活性的内生真菌进行分子鉴定。结果表明:(1)从剑叶龙血树茎、叶中共分离得到345株内生真菌,294株对一种以上指示菌有抑制活性;(2)其中84株内生真菌对5株临床耐药菌均有不同程度的抑制活性,占所分离菌株总数的24.35%,75%的内生真菌对金黄色葡萄球菌有抑制活性。这说明剑叶龙血树中存在多种有抑菌活性的内生真菌,为剑叶龙血树内生菌抗菌活性成分挖掘及新型抗菌药物筛选奠定了基础。

Abstract:

To explore the resource diversity and antimicrobial capability of endophytic fungi from the endangered Dracaena cochinchinensis, and mine novel antimicrobial secondary metabolites from talent strains, endophytic fungi were isolated from stem and leaf tissues of D. cochinchinensis. All isolated strains were cultured in liquid media for seven days, the culture media were extracted with ethyl acetate and then used to estimate the antimicrobial activities against 10 pathogenic bacteria and 5 drug-resistance pathogens by using the oxford-cup test. The results were as follows:(1)345 strains were isolated and 294 of which displayed antimicrobial activities against more than one pathogen;(2)Among them, 84 endophytes(accounted for 24.35%)displayed potent inhibition against 5 drug-resistance pathogens to very degrees and 75% endophytes displayed obvious inhibition against Staphylococcus aureus. Accordingly, 40 talent strains were selected and identified to 32 species by phylogenetic analysis based on ITS sequencing. This study indicated that diverse endophytic fungi with strong antimicrobial activities inhabiting in D. cochinchinensis, which could be potential for developing antimicrobial reagents.