几株类棒束孢菌株分类地位的修订

【背景】粉棒束孢是自然环境中常见的一种昆虫病原真菌,全球广泛分布且寄主多样。然而,棒束孢属许多种形态学特征相似,仅根据经典形态学鉴定容易出现错乱现象。长期以来依据形态特征鉴定为粉棒束孢的菌株,其准确的分类地位出现了越来越多的争议。最近,该属起源被确定是多系发生的。【目的】明确粉棒束孢的分类沿革并探究先前被鉴定为粉棒束孢菌株的准确分类地位。【方法】选取6株先前被鉴定为粉棒束孢的菌株,对其进行经典形态观察,并扩增5个基因位点(nrSSU、nrLSU、TEF、RPB1和RPB2)的基因序列,进行多基因分子系统发育学分析。【结果】通过查阅文献和实验研究,明确了粉棒束孢分类研究的历史沿革;供试的6株不同来源的菌株与粉棒束孢模式种亲缘关系较远,而与新成立的组合种Samsoniella hepiali完全一致。【结论】利用经典形态学特征和构建5个基因系统发育树,重新修订6株类棒束孢菌株的正确分类地位为Samsoniella hepiali。为该类昆虫病原真菌正确分类提供合理的方法,也为开发和利用该类菌株提供科学的指导。

Revision of taxonomic status of several Isaria-like strains

[Background] Isaria farinosa with global distribution and wide host range is one of common entomopathogenic fungi in natural environment. However, the morphological characteristics of many species of Isaria are similar, which are easy to be confused only according to the classical morphological identifications. For a long time, more and more controversies and confusions have emerged on the accurate classification status of the strains identified as I. farinosa according to their morphological characteristics. Recently, its phylogeny has proved multigenus. [Objective] To clarify the taxonomic position of I. farinosa and explore the natural taxonomic status of the strains which were previously identified as I. farinosa. [Methods] Six strains previously identified as I. farinosa were selected for phylogenetic analysis of five gene loci (nrSSU, nrLSU, TEF, RPB1 and RPB2) and morphological methods to reconfirmed their taxonomic status. [Results] Through checking on the literature and experimental research, the phylogeny of I. farinosa was clarified. The results showed that all the tested strains from different sources were far related to the model strain of I. farinosa, but they are identical to a new combination species Samsoniella hepiali. [Conclusion] In this study, the correct taxonomic status of 6 Isaria-like strains was revised as S. hepiali by using the classical morphological characteristics and constructing the five genes phylogenetic tree. To provides a reasonable method for the correct identification of Isaria-like fungi and scientific guidance for further utilization of these strains.