1株重寄生真菌粉棒束孢鉴定及系统发育分析

Identifying a Sporocarp-inhabiting Fungus Isaria farinosa and Analyzing Its Molecula Phylogeny of ITS Sequence

报道寄生于蛹虫草子座尖端的1种真菌(No.YHIFXS-I001),通过形态和ITS测序鉴定其为粉棒束孢。研究发现,该粉棒束孢菌株具有长锥形,基部膨大、尖端变细的两型分生孢子梗,长链以及单孢两型分生孢子连结方式,拓宽了对粉棒束孢寄生式样和显微特征的认识。另外,对该菌株开展ITS测序分析,通过与GenBank中粉棒束孢ITS序列的整理和比较,确定NCBI数据库中粉棒束孢9条ITS序列为错误鉴定,同时解析了粉棒束孢种内ITS序列较低的遗传丰富度(单倍型多样性Hd为0.590,核苷酸多样性P i为0.00378)。利用ITS对粉棒束孢及其近缘物种分子系统学分析,发现粉棒束孢与其它棒束孢物种形成多系关系,这一结果揭示了棒束孢属3系分支的系统分类格局,暗示粉棒束孢与其他棒束物种进化差异,对其系统学研究将有启示作用。

A fungi strain （No. YHIFXS - 1001 ） was isolated from the stroma of Cordyceps militaris collected in Xishan Mountains, Kunming, Yunnan. The morphological and microscopic features were observed. It was showon that the strain had 2 types of conidiophore, i. e., long conical, base enlargement and tip tapering stems. And long chain link type and single spore co- nidium were discovered. It was benefit for understanding the parasitic styles and microscopic features of Isaria spp. In addition, the ITS sequences of this strain was determined, comparing to the other ITS sequences in GenBank. It was clarified that nine ITS sequences were mistaken an identification as lsariafarinosa. The rest was found to be lower genetic richness （Hd= 0. 590, Pi -- 0. 003 78） in Isaria farinosa. By analyzing molecular phylogeny of ITS sequences, Isaria spp. were divided into three branchs, not being monophyly. It was polyphylic for the relationships between Isaria farinosa and the other species of Isaria. The results showed that there were polyphylic structures in the genus Isaria. It was implied to be need systematic research of Isaria further.