Molecular Systematics and Evolution of the Mycenoid Fungi (Euagarics, Basidiomycetes)

真菌是地球上最多样化的生物群体之一，它们在陆地生态系统的功能、维持和进化中发挥着许多重要作用。然而，对它们的研究仍然很少。本项目研究蕈属菌丝体及其相关属的分类和系统，统称为类菌丝体真菌。菌丝体真菌有2000多个已命名的物种，分布在60个已描述的属中，是世界上最多样化的蘑菇类群之一，在热带地区具有很高的分类多样性。迄今为止，这些真菌没有一个全面的分类系统，它们的进化关系（谱系或系统发育关系）仍然很大程度上是未知的。系统发育信息的缺乏阻碍了对物种分布、起源和扩散（生物地理学）的推断。它也阻碍了关于真菌形态和生物化学进化的生态学和环境约束的详细研究，例如鳃状，多孔状和简化形式之间的逆转，或真菌在自然界中生物发光的意义。在这个项目中，研究人员建议通过对大约300个热带和温带物种的三个核基因和两个线粒体基因的核苷酸序列数据进行采样和分析，构建一个强大的类真菌系统发育，这些物种要么已经掌握，要么将从野外收集。蕈类真菌是世界范围内森林生态系统中分布最广、数量最多的蘑菇之一，具有重要的生物学意义。该组大部分成员是凋落物分解者，因此它们在碳循环，土壤养分周转，土壤发生以及通过凋落物结合减少侵蚀方面发挥重要作用。据报道，一些物种是经济上重要的作物（如咖啡或可可）的植物病原体，其他物种是兰花根的共生体。此外，由于数量丰富，这些真菌是无数动物的主要食物来源，因此在食物网中起着核心作用。本研究将提供的对类菌丝体真菌的进化史和生物地理分布模式的透彻理解，将使研究人员对有助于生物多样性产生和维持的过程有更多的了解。这对于制定有关保护和土地管理政策的决策，以及更好地了解和监测本地和入侵物种的扩散或萎缩具有明显的影响。该研究结果也将为进一步研究真菌在森林生态系统功能中的作用提供新的数据。该项目是对其他正在进行的nsf资助项目的补充和支持，包括对旧金山州立大学Dennis Desjardin博士的PEET资助，旨在培训年轻的真菌分类学家，以继续加强系统生物学，以及组装真菌生命树计划。本项目将资助泰国清迈大学一名博士后、几名本科生和一名亚洲博士生。

Fungi are among the most diverse groups of organisms on Earth, and they play many essential roles in the function, maintenance, and evolution of terrestrial ecosystems. Yet, they remain poorly studied. This project is concerned with taxonomy and systematics in the mushroom genus Mycena and allied genera, together referred to as the mycenoid fungi. With over 2000 named species distributed in about 60 described genera, the mycenoid fungi represent one of the most diverse groups of mushrooms in theworld, with high taxonomic diversity in tropical regions. To date, no comprehensive classification system exists for these fungi, and their evolutionary relationships (genealogical or phylogenetic relationships) are still largely unknown. This lack of phylogenetic information hampers inferences about species distribution, origin, and dispersal (biogeography). It also prevents detailed studies about the evolution of fungal morphology and biochemistry with respect to ecology and environmental constraints, such as the reversal between gilled, poroid, and reduced forms, or the significance of fungal bioluminescence in nature. In this project, the investigators propose to construct a robust phylogeny for mycenoid fungi by sampling and analyzing nucleotide sequence data from three nuclear and two mitochondrial genes for approximately 300 tropical and temperate species, either already in hand or to be collected from the field. Mycenoid fungi are biologically significant for they are among the most widespread and abundant mushrooms in forest ecosystems worldwide. Most members of the group are litter decomposers, thus they play major roles in carbon cycling, turnover of soil nutrients, soil genesis, and the reduction of erosion via litter binding. A few species have been reported to be plant pathogens on economically important crops such as coffee or cacao, and others as symbionts with orchid roots. Also, because they are abundant, these fungi serve as a major food source for innumerable animals thereby playing a central role in the food web. The thorough understanding of the evolutionary history and biogeographic distribution patterns of mycenoid fungi that this study will provide will allow investigators to gain additional insights on the processes that contribute to the generation and maintenance of biological diversity. This has clear implications whenmaking decisions regarding conservation and land management policy, and also for better understanding and monitoring the spread or shrinkage of native and invasive species. Results from this research will also provide novel data for further investigation on the role of fungi in the function of forest ecosystems. This project is complementary to and supportive of other ongoing NSF-funded projects, including a PEET grant to Dr Dennis Desjardin at San Francisco State University that aims at training young fungal taxonomists for continued enhancement of systematic biology, and to the Assembling the Fungal Tree of Life initiative. This project will support a postdoctoral associate, several undergraduate students, and one Asian PhD candidate at Chiang Mai University in Thailand.