横断山区线虫草科物种分类、系统发育与线粒体基因组进化

The species diversity of fungi is extremely abundant in the Hengduan Mountains region, however, the understanding of Cordyceps sensu lato resources is still not clear. In particular, here species relationships of the family Ophiocordycipitaceae are confused, as well as their taxonomy, systematics and evolution are poorly studied. A large-scale survey, collection and resource germplasm bank of species within Ophiocordycipitaceae in the Hengduan Mountains region will be conducted in this project. Identification and description of species within Ophiocordycipitaceae will be carried out using polyphasic taxonomy (combining morphology, ecology and molecular phylogeny). Based on nuclear and mitochondrial gene datasets, group evolutionary time analyzed by molecular clock will be combined to construct the phylogenetic framework of Ophiocordycipitaceae. Consequently, taxonomic status of new species within Ophiocordycipitaceae in the Hengduan Mountains region will be determined, and taxonomic revision for species with incorrect classification or dubious position will be generated. Based on whole genome sequencing data, mitogenomic assembly and annotation will be carried out to analyze mitogenomic characteristics and genetic variation, as well as correlation between species differentiation of Ophiocordycipitaceae and geological historical events of orogeny in the Hengduan Mountains region. The propagation route of core groups in this region will be speculated, and adaptive evolution of their mitogenomes will be revealed. Moreover, molecular mechanism of adaptive evolution of species within Ophiocordycipitaceae in the Hengduan Mountains region will be further explored. This study provides a theoretical basis for the conservation and sustainable utilization of Cordyceps s. l. resources and has important innovative significance and scientific value.

横断山区真菌物种多样性极其丰富，但对虫草资源的认识仍不甚清楚。尤其是，该区域的线虫草科物种关系混乱，对此类群分类、系统与进化研究较薄弱。项目拟对横断山区线虫草科物种资源进行大规模调查和收集，建立物种资源种质库。利用多相分类学方法（结合形态学、生态学和分子系统学），鉴定和描述横断山区线虫草科物种。基于核基因和线粒体基因数据集，结合分子钟分析类群进化时间，构建线虫草科系统发育框架，确定横断山区线虫草科新物种的分类地位，对分类位置不定或处理错误的物种进行修订。利用全基因组测序数据进行线粒体基因组组装和注释，解析横断山区线虫草科物种线粒体基因组特征、遗传变异以及该地区线虫草科物种分化与造山运动地质历史事件关联性，推测该地区核心类群传播途径；揭示其线粒体基因组适应性进化，进一步探讨横断山区线虫草科物种适应性进化分子机制。本研究为虫草资源保护与可持续利用提供理论依据，具有重要的创新意义和科学价值。

调查和收集横断山区及周边地区广义虫草资源，收集标本3000余份，保藏菌株1300余株，获得物种220余个（其中新分类群60余个）。收集线虫草科标本2000余份，分离保存菌株600余株，物种98个。整合形态学、生态学、核基因和线粒体基因系统发育学分析，构建肉座菌目系统发育框架，将多头霉属及近缘类群从线虫草科独立出来，建立新科多头霉科。通过多项分类法界定线虫草科中线虫草属物种72个（新种38个、中国新记录种8个）、弯颈霉属物种6个（新种2个）、紫孢霉属已知物种3个，界定其他近缘分类群100余个（多头霉科、虫草科和麦角菌科）。基于二代测序技术对线虫草科和多头霉科物种进行基因组测序，组装全基因组47个，组装、注释和分析7个属49个物种完整线粒体基因组。基于线粒体基因组数据，结合分子钟分析，解析了横断山区线虫草科物种线粒体基因组特征和遗传规律，推测了该地区核心类群的传播途径；探讨了其线粒体基因组适应性进化机制。研究成果将有助于进一步探讨广义虫草系统发育与适应性进化规律，为虫草资源的开发利用提供战略储备，具有科学意义和创新性。