腐质霉属及其近似属嗜热丝孢菌属的分类及分子系统学研究

The fungi of Humicola and Thermomyces genera have important economic and ecological value. For a long time, because conidiophores are very short or lack with most species in two genera, the taxonomic criteria of both genera mainly were based on the size and morphological characteristics of conidia. Thus, the delimitation factors between these two genus were ambiguous, and similarity was obvious. There was a great divarication for whether Thermomyces was one synonym of Humicola. The taxonomic confusion on the level of generic and species level was caused by the morphological species could not be delimited clearly and the delimitation criteria of species which were variable and easily affected by environment and cultural condition. Meanwhile, traditionally taxonomy of this fungal group based on morphology was not enough to reflect the evolutionary relationship and was very difficult to identify some ambiguous taxa. This project draws up to use the sequences of three DNA markers (rDNA ITS, EF1а、RPB2) to construct phylogenetic trees and to analyze the phylogenetic relationship of these two genera and species. Hopefully the new taxonomic system and evolutionary relationship suitable for this fungal group were rebuilt by combining the morphology, ecology and phylogeny. Some ambiguous taxa or related species were re-identified. The results will provide the support for systematically developing the taxonomic research of other fungal groups in hyphomycetes.

腐质霉属与嗜热丝孢菌属真菌具重要的经济学及生态学意义。长期以来，由于两属多数种分生孢子梗很短或缺，两属的分类都主要依据侧生厚垣孢子的大小和形态，两属间界定因子不清晰，相似性明显，后者是否为前者的异名属存在很大分歧，用于种间界定的特征都是多变而连续的数量性状且易受环境或培养条件的影响，形态物种间界限不清晰，导致了属、种分类研究的混乱。另外，传统上该类群真菌的形态学划分依据不足反映属、种的系统发育关系，也难以作为一些疑难种的鉴定依据，本项目拟以模式标本或菌株为基础，采用rDNA ITS、EF1а、RPB2基因序列构建系统发育树，分析确定两属、种间系统发育关系，通过形态、生态等表型生物学特征与基因型特征相结合建立适宜该类群趋于自然的新分类系统和演化关系；并以此为依据对两属进行重新界定和划分，澄清部分疑难种或相似种的分类地位。该研究将为深入开展暗色丝孢真菌其它类群真菌的系统分类研究提供技术支持。