白花曼陀罗内生真菌多样性及抗皮肤真菌活性分析

Diversity and Anti-Dermatophyte Activities of Endophytic Fungi from Datura metel

目的:分析白花曼陀罗各部位内生真菌的类群结构与多样性,并筛选出具有抗皮肤真菌的活性菌株,为寻找新的抗皮肤真菌先导化合物提供菌株资源。方法:采用组织块法对白花曼陀罗根、茎、叶3个部位的内生真菌进行分离,结合形态学和rDNA-内转录间隔区(ITS)序列分析法对内生真菌进行鉴定,利用琼脂扩散法分析其抗皮肤真菌活性。结果:该研究从白花曼陀罗中分离到292株内生真菌,隶属于34个属,其中根部内生真菌的优势类群为镰刀菌属(Fusarium)占72.97%,茎部以镰刀菌属(37.25%)和Plectosphaerella(28.43%)为主要类群,而炭疽属(Colletotrichum)在叶部的比例最高,达39.66%;叶部内生真菌的分离率(89.23%),定殖率(84.62%)和多样性指数(1.82)明显高于根(70.48%,70.48%,1.23)和茎(69.39%,68.03%,1.64)。35代表性内生真菌发酵液的抗皮肤真菌活性结果表明,它们对犬小孢子菌,黏性毛孢子菌,红毛癣菌、白色念珠菌等皮肤致病真菌的具有抑制作用的菌株分别占总数的97.14%,71.43%,45.71%,25.71%,其中有6株(17.14%)对4种皮肤致病真菌均具有抑制活性,它们分别是Fusarium sp. R1,Penicillium sp. R5,Aspergillus sp. R7,Metarhizium sp. S18,Diaporthe sp. S19和Glomerella sp. L57。结论:白花曼陀罗内生真菌具有丰富的物种多样性,其中存在较高比例的具抗皮肤真菌活性菌株,为寻找新的抗皮肤真菌药物提供了菌株资源。

Objective: To investigate the taxonomic structure and diversity of endophytic fungi from Datura metel and screen the strains with anti-dermatophyte activities, so as to provide resources for the development of new lead compounds against dermatomycosis. Method: Endophytic fungi were isolated from the roots,stems and leaves of D. metel after tissue block incubation and then identified by morphological analysis and rDNA-internal transcribed spacer(ITS)sequencing. Their anti-dermatophyte activities were detected by agar diffusion assay. Result: A total of 292 strains of endophytic fungi were isolated from D. metel,belonging to 34 genera,with Fusarium(72.97%)in roots,Fusarium(37.25%)and Plectosphaerella(28.43%)in stems,and Colletotrichum(39.66%)in leaves as the dominant species. The isolation rate(89.23%),colonization rate(84.62%),and diversity index(1.82)of endophytic fungi in leaves were significantly higher than those in roots(70.48%,70.48% and 1.23)and stems(69.39%,68.03% and 1.64). The determination of anti-dermatophyte activities of 35 endophytic fungal fermented filtrates showed that the strains exhibiting inhibitory activities against Microsporum canis,Trichosporon mucoides,Trichophyton rubrum and Candida albicans accounted for 97.14%, 71.43%, 45.71%, and 25.71%, respectively. Among them, six strains(17.14%),namely Fusarium sp. R1,Penicillium sp. R5,Aspergillus sp. R7,Metarhizium sp. S18,Diaporthe sp. S19,and Glomerella sp. L57,all inhibited the four types of cutaneous fungal pathogens. Conclusion: The endophytic fungi in D. metel are diverse,and the proportion of endophytic fungi possessing anti-dermatophyte activities is high,allowing them to serve as potential resources for the development of new anti-dermatophyte agents.