中国Hydnellum和Sarcodon属分类及系统学研究

Hydnellum and Sarcodon are the genera in Thelephorales, Basidiomycota. Species of the two genera have closely phylogenetic relationships because they share similar a terristrial habitat, pileus and stipes and brown, warted basidiospores. As the ectomycorrhizal fungi, the species of these two genera have widely distribution in the different type of forests of the world, and play the important ecological functions. Around 90 species have been described in this group hitherto known in the world, and only 8 species were recorded in China. The field investigation, taxanomy and molecular phylogenetic studies were inadequate. Species structures were changed and the fruiting bodies distinctly decreased in the condition of global nitrogen deposition. Thus, it is necessary and urgent to carry out the classification and systematic research as soon as possible. In this project, extensive investigations, comprehensive taxonomy and multi-genes analyses will be carried out, and the distribution information of the specimens with the different environmental factors will be recorded. The aims are to find and describe the new taxonomic units, clarify the phylogenetic status of the species and phylogenetic relationships among them, evaluate and revise the present taxonomic framework, and try to establish the scientific and natural taxonomic system. The expected results will include several new species and new records, provide a latest information on species diversity, ecological distribution and phylogeny for this group of fungi in China, and provide scientific basis for conservation and utilization of the bioresources.

Hydnellum和Sarcodon两属是担子菌门疣孢革菌目中的重要类群，地生并具菌盖和中生菌柄，都产生棕褐色并具疣状突起的孢子，两者具有密切的系统发育关系。该类群为外生菌根真菌，在多种生态类型森林中广泛分布，具有非常重要的生态学功能。两属世界范围内已描述约90种，我国仅记载8种，缺乏系统的采集和研究。全球氮沉降使该类群物种结构发生改变，子实体数量显著减少，尽早对其开展分类和系统学研究具有必要性和紧迫性。本项目拟对我国该类群真菌进行广泛的标本采集，记录各种类的分布区域及环境因子，以形态学研究方法与多基因序列分析相结合，对标本进行全面和系统的研究，发现和描述新物种，探明两属各种类的系统发育地位及其相互关系，对现有的分类系统进行评价和修订，构建更趋科学和符合自然的分类系统。本项目预期将发现若干我国真菌新物种和新记录种，明确其物种多样性、生态分布和系统发育关系，为资源的保护和利用提供科学依据。

Hydnellum和Sarcodon两属是担子菌门疣孢革菌目中的重要类群，两属的系统发育关系极为密切。作为外生菌根真菌，两属物种在多种生态类型森林中广泛分布，具有重要的生态学功能，此外很多物种为食药用真菌。在全球气候变化和人类活动干扰的背景下，该类群物种子实体数量显著下降，而我国对两属还缺乏系统的采集和多样性研究，因此对其开展分类和系统学研究具有必要性和紧迫性。在本项目的支持下，课题组对我国各重点区域的主要自然保护区和森林公园等进行了野外调查和标本采集，记录各物种的分布地的生态及环境因子，以形态学与多基因序列分析方法相结合，对该类群标本进行全面和系统的研究。以最大似然法和贝叶斯推导构建的多基因系统发育树显示，多数能够代表属下等级分类单元的分支均获得了较高的支持率，结合子实体形态学特征，特别是菌盖和菌肉颜色、质地、表面特征、菌齿和菌柄形态，以及显微结构中的担孢子大小、形状、表面纹饰、菌丝系统等重要特征，特别是菌齿和菌肉中菌丝分隔类型以及简单分隔和锁状联合出现的比例，提出了属下等级的区分特征，并建立了10个亚属；确认了狭义的Sarcodon属所包含的种类，并验证了该属与Hydnellum属间的形态学界限；经与模式种特征比对发现14个新种，4个中国新记录种，另有5个为可能的新种，完成了这些物种的描述、命名、显微结构绘图、扫描电镜、以及系统发育分析等研究，并已合法发表。研究基本明确该类群的物种多样性和生态分布，探明两属种类间的系统发育地位及其系统学关系，对现有的分类系统进行评价和修订，构建了更科学和符合自然的分类系统，为资源的保护和利用提供科学依据。