多头霉系统发育及寄主适应性进化研究

The Polycephalomyces group reflects complex diversities of morphology and ecology in Hypocreales. Morphological characteristics is much various in this group and its species have complicated associations with their hosts. It remains an incertae sedis member in Hypocreales as insufficient sampling of taxon and unclear understanding. The most extensive sampling of taxon will be conducted among Polycephalomyces and its related families, and molecular phylogeny will be investigated using ITS and 5-gene (nrSSU, nrLSU, tef-1α, rpb1 and rpb2) datasets in this project. Species identification and description will be performed, combining morphological and ecological characteristics. Combining the two and three generations of genome sequencing technologies, twenty typical species will be selected for de novo sequencing. In order to uncover the phylogenomic relationships between Polycephalomyces and its related families, the concatenated nucleotide sequences of single-copy genes will be applied to constuct a phylogenomic tree of Hypocreales. A taxonomic revision for Polycephalomyces will be finished, with combining morphology, ecology and phylogenomics. The speciation in Polycephalomyces and its host adaptation will be revealed through the comparative genomics research.

多头霉是肉座菌目中形态学和生态学多样性复杂的类群，物种形态特征差异较大，其与寄主的关系复杂多样。由于对多头霉取样和研究不全面，其在肉座菌目中分类位置不确定。项目拟对肉座菌目中多头霉及其近缘科进行取样，通过ITS和5基因（nrSSU、nrLSU、tef-1α、rpb1和rpb2）联合数据构建系统发育树，结合形态学和生态学特征，对多头霉物种鉴定和描述。结合二代与三代基因组测序技术，选取20个典型物种开展de novo测序。利用肉座菌目所共有单拷贝同源蛋白编码基因的核酸序列串联数据集，构建多头霉及其近缘科的系统发育树，从系统发育基因组学角度，阐明多头霉物种间及其与近缘科的系统发育关系。结合形态学、生态学和系统发育基因组学特征，对多头霉进行分类修订。通过比较基因组学研究，揭示多头霉物种形成及寄主适应性进化机制。

多头霉是肉座菌目中形态学和生态学多样性复杂的类群，物种形态特征差异较大，其与寄主的关系复杂多样。由于对多头霉取样和研究不全面，其在肉座菌目中分类位置不确定。项目调查和收集国内外虫草资源，调查和收集多头霉类群物种36个，采集标本300余份，分离保存菌株198株，建立多头霉种质资源库。对肉座菌目进行大范围取样，整合形态学、生态学、6基因（ITS、nrSSU、nrLSU、tef-1α、rpb1和rpb2）系统发育学、线粒体和核基因组系统发育基因组学分析，构建肉座菌目系统发育框架，对多头霉类群进行分类修订。建立新科Polycephalomycetaceae fam. nov.,容纳4个属（包括2个新属），即多头霉属Polycephalomyces（已知种1个、新组合种1个、新种1个）、多年虫草属Perennicordyceps（已知种5个、新组合种1个、新种3个）、无柄虫草属Sessiliocordyceps gen. nov.（新组合种1个）、新多头霉属Neopolycephalomyces gen. nov.（新组合种17个、新种13个）。完成多头霉科24个物种及宿主线虫草科5个物种全基因组测序。分析了多头霉科12个分类单元的线粒体基因组特征及其进化规律。通过对多头霉科12个分类单元全基因组组装和注释，结果发现其基因组大小范围为 30～90.1 Mb。多头霉科物种进行基因家族扩张和收缩分析表明多头霉科在进化过程中，获得了大量基因家族，拥有很强的环境适应和次生代谢产物合成的能力。多头霉科由宿主专一型物种、中间型过渡物种向广谱型物种方向基因家族大量扩张，表现出与宿主协同适应进化的特征。利用Network分析多头霉与其它真菌共生模式，结果表明多头霉与宿主内源的其他真菌物种具有较强相互作用。