白环蘑属（蘑菇科）真菌的分类及分子系统发育研究

Leucoagaricus is a morphologically diverse genus which is distributed worldwide, and it is one of the most taxonomically difficult groups within the family Agaricaceae. Our preliminary results based on morphological and molecular data suggest that: (1) the extent of its diversity in tropical area remains poorly known and a bunch of putative novel species need to be confirmed by further investigation. (2) Leucoagaricus is not a monophyletic group; It forms several clades with some species interspersed within Leucocoprinus. Some of the clades may represent generic novel taxa which need to be further confirmed by scrutinizing morphological observations and multiple gene phylogenetic analyses; (3) A recent study which demonstrates two unidentified Micropsalliota species clustered with Leucoagaricus suggests that Micropsalliota may have close relationship with Leucoagaricus, and this hypethesis need to be tested by sampling more Micropsalliota species. Using extensive taxa sampling strategy and a multiple gene phylogeny approach, the aims of this project are: (1) To inventory the species diversity of Leucoagaricus and Micropsalliota in China by crucial morphological observations and molecular phylogenetic analyses based on specimens resulted from extensive field trip collections. (2) To define generic limits of Leucoagaricus and its allied genera within Agaricaceae and to elucidate the phylogenetic relationships between Leucoagaricus and Micropsalliota.(3) To establish an authoritative phylogenetic classification system for Leucoagaricus species based on multiple gene sequences and morphological characters. This project will provide taxonomic training for at least two graduate students, and will certainly contribute to understanding of the taxonomy, phylogeny and evolution of the family Agaricaceae.

白环蘑属真菌分布广泛，形态结构多样，系统亲缘关系复杂，是蘑菇科研究中较为困难的类群。申请人前期研究发现：1.白环蘑属真菌在热带地区有许多新分类单元亟待认识、描述；2.白环蘑属不是单系类群，而是嵌套于白鬼伞属中形成若干独立分支，其中几个支系可能代表了不同的新属，亟待加大取样密度和增加基因片段深入研究和界定；3.最新的研究结果暗示小蘑菇属可能与白环蘑属有亲缘关系，这种假说有待检验。本项目拟对白环蘑属和小蘑菇属真菌进行广泛取样，开展细致的形态解剖学和基于多基因片段的分子系统发育研究，通过综合分析，旨在：1.深入认识白环蘑属和小蘑菇属真菌的物种多样性，发表若干新的分类单元（属、种）；2.阐明白环蘑属和小蘑菇属间和属下各主要支系间的系统发育关系；3.掌握区分各单系的关键特征，提出有综合证据支持、能反映进化关系的白环蘑属真菌的分类系统。本研究对认识蘑菇科的物种多样性、系统发育及演化具有重要的科学意义。

白环蘑属真菌分布广泛，形态结构多样，系统亲缘关系复杂，是蘑菇科研究中较为困难的类群。课题组按照项目计划书的内容，在研究国内外各大标本馆馆藏标本基础上，结合野外调查和采集，对白环蘑属及相关类群作了分类学和分子系统发育研究，主要的科学发现如下：.1）发现新属2个（Pseudolaccaria和Pseudolepiota）、新物种11个、新组合6个。中国新记录属5个（Coniolepiota、Heinemannomyces、Micropsalliota、Smithiomyces、Verrucospora）；极大了促进了对我国蘑菇科在属、种水平上的多样性的认识。.2）传统意义上的白环蘑属不是单系类群，该属物种在系统树上聚为4个主要分支：/leucocoprinus分支、/leucoagaricus分支、/sericeomyces分支和/flammeotincta分支，其中的/flammeotincta代表了一个新属；.3）以前被认为白环蘑属下的丝盖环柄菇亚属Sericeomyces是一个单系群，应独立为属，但属的概念应该进行如下修订；菌盖表皮由长形的、近不分化的、呈平伏状或辐射状排列的菌丝组成，担孢子为卵形至杏仁形、孢子近顶端缢缩变尖，无芽孔；.4）与同样具有褐色菌褶的蘑菇属相比，小蘑菇属与白环蘑属亲缘关系更近，与美洲白环蘑和鸡珠白环蘑共同开成一个单系群。中国至少有小蘑菇属真菌17种，其中6个种为新种；.5）积累了大型真菌标本近2900号，其中白环蘑属及相关类群真菌240号；发现一个具白色菌褶的蘑菇科新属Pseudolepiota，该属在系统发育上与蘑菇科中具褐色孢子的蘑菇属Agaricus较近，而不是与白色孢子的类群如环柄菇属Lepiota、白环蘑Leucoagaricus等。.迄今为止项目组已经发表了标注本项目资助的研究论文6篇，在审国内核心期刊论文1篇。