马比木内生刺盘孢属真菌的分布多样性

Diversity and distribution of endophytic Colletotrichum in Nothapodytes pittosporoides

马比木是具有抗癌活性的药用植物,前期实验从不同地区、不同部位的马比木植株中分离得到1339个内生真菌菌株,ITS序列分析结果表明隶属于刺盘孢属的菌株有268个,说明刺盘孢属为马比木内生真菌的优势属之一。为了解马比木中刺盘孢属菌株的多样性,本研究按不同地区、不同部位归类,分析刺盘孢属菌株的地域和部位分布特征。选择31株代表菌株与参考菌株的ITS-TUB2-ACT-GAPDH 4个基因片段联合分析,通过分子系统发育和形态学结合的方法对代表菌株进行分析。结果显示,从分离部位上看,除花以外,其他部位均有刺盘孢属真菌的分布,叶和茎为主要分离部位;从分离地区上看,每个地区均分离到刺盘孢属菌株,但分离数量差异较大,贵阳和吉首的分离数量较大。多基因系统发育树将选择的31株代表菌株分成了19个操作分类单位(OTUs)。以上结果表明,马比木中不同生境的内生刺盘孢属菌株表现出一定的偏好和选择性,但没有明显的特异性;马比木内生刺盘孢属真菌具有较高的多样性。

Nothapodytes pittosporoides is a medicinal plant with anticancer activity.In our experiment,1339 endophytic fungal isolates were obtained from Nothapodytes pittosporoides in different regions and plant parts.The result of preliminary ITS DNA sequence analysis showed that there were 268 isolates belonging to Colletotrichum,indicating Colletotrichum was one of the most dominant genera of endophytic fungi in Nothapodytes pittosporoides.A total of 31 representative isolates was selected for phylogenetic analysis based on DNA sequence data(ITS,GAPDH,ACT and TUB2)and morphology.The results showed that Colletotrichum hyphae were distributed in all parts of plant except for flowers,and leave and stems were the main sources of the isolates.Colletotrichum distributed in all areas investigated but the isolation frequencies varied with different localities.It seems that Guiyang and Jishou are most aboundant.The selected 31 representative isolates were divided into 19 operational taxonomic units(OTUs).Our results showed that Colletotrichum in Nothapodytes pittosporoides had certain preference and selectivity toward habitats,but no obvious specificity.