中国乳牛肝菌属及其两个重要复合群的系统学和生物地理学研究

Suillus is a genus of monophyletic fungi in the family Suillaceae and order Boletales,Basidiomycota. Species in the genus which associated with some coniferous trees have important disquisitive, ecological and economic value. By the modern taxonomy and molecular phylogeny research methods, try to break through the bottle necks of the changeable and continuous quantitative characters on the basis of the understanding of each morphological character in the genus. Clarify the species composition of the genus Suillus in China, reveal geographical regularity, and revised the under genus classification system. The study materials include the type specimens and the specimen in Suillus sensu lato which are from China, the neighborhoods and type localities in the world. The Suillus viscidus-complex and Suillus granulatus-complex have intercontinental disjunction distribution pattens and separated associate with the Larix and Pinus trees, they are the ideal material for the study of phylogenetic and biogeographic relationships. According to the morphological characteristics, divide the species of the complex into different morphotypes; by sifting identifies gene fragments, constructing phylogenetic trees, to reveal the species diversity of the two complexes. To confirm the symbiotic tree species; to expound relationships between the Suillus species and the biogeographic factors such as the trees, the elevation, longitude, latitude and so on. To analysis their genesis and coevolution, as well as geographic distribution patterns. Try to discuss and explanation on the host transfer and their selection having effect on the species development, migration and geographic distribution.

乳牛肝菌属（Suillus Gray）是牛肝菌目中系统位置独特，且具有重要生态、经济价值的研究类群。本研究应用现代分类学和分子系统学相结合的研究手段，在对各个形态特征权重的理解和应用上，突破各类群间多变和过渡数量性状所造成的瓶颈，以我国及邻近地区的广义乳牛肝菌属真菌作为主要研究材料，对比全球涉及有关种群的模式或模式产地标本，澄清我国乳牛肝菌属种类组成，揭示地理分布式样及其规律，修订属下分类系统。粘乳牛肝菌复合群和点柄乳牛肝菌复合群具有典型的洲际间断分布式样，按照形态特征分为形态型（morphotypes），筛选标识基因片段建立系统发育树，明确共生树种，揭示两个复合群的物种多样性和物种间及居群间的系统发育关系，探索与共生树种的协同演化关系，阐明与共生树种、海拔高度、经纬度等生物地理要素的关系，分析各物种的地理分布格局及可能成因。探讨乳牛肝菌宿主选择或宿主转移对于物种演化、迁移等事件的影响。

本课题研究了采自我国各省（除海南岛）的1000 余份乳牛肝菌属标本，并与北美和欧洲种300余份材料分析对比，应用了最新全球ITS序列鉴定出63个乳⽜牛肝菌OTUs，所 提供的样品占了已测序全球乳⽜牛肝菌物种多样性的89%。通过 rDNA-ITS、rDNA-LSU、TEF1、RPB1和RPB2基因片段，运用最大似然法和贝叶斯法对世界乳牛肝菌的多样性、生物地理和宿主共生植物进行了分子系统发育分析。确认乳牛肝菌在我国分布有42个种，其中16个为可发表的新种， 10个新记录种。明晰了乳牛肝菌在我国物种多样性及其地理分布、分类学鉴别特征以及和松科植物的共生关系。研究查清了全球点柄乳⽜牛肝菌复合群包括三个物种；粘乳牛肝菌复合群包含有两大单系，其中一个单系分布在喜马拉雅地区；另⼀个单系使用多基因分析仍然是一个复合群，包含约6或7个物种。首次提出亚属划分的分子依据，将乳⽜牛肝菌属分为显著支持的六个亚属，主要鉴定依据为宿主共生植物-松科植物。通过乳牛肝菌类宿主专⼀性与祖先宿主重建，为松科植物的进化史提供新了的佐证，确认了松属外生菌根菌化石不是乳牛肝菌属的真菌。通过对乳⽜牛肝菌的地理分布与祖先分布重建，发现其祖先主要分布于东亚北部以及美洲西部⾄至墨西哥等中美洲地区。