Biogeography and Speciation in the Oyster Mushroom Pleurotus

担子菌属平菇属（Pleurotus）是一种重要的木材降解真菌，在许多国家都有采集或栽培的食用菌。杜克大学的Rytas Vilgalys教授正在研究该属在全球分布的物种差异模式。利用从实地考察和同事那里收集的大量样本，将形态学和交配系统的传统分类学研究与核糖体基因序列的现代分析结合起来。将进行实验室生长研究，以确定交配系统和不育群的限度。研究人员还采用了一种简单而巧妙的“孢子捕获”技术，即将装有几种测试菌株的培养皿暴露在当地孢子雨中48小时，并监测菌丝融合的结果。同步分子分析的重点是来自世界各地的平菇样本的DNA序列数据。这些研究结果将有助于回答与真菌物种形成有关的几个问题：(1)在分子钟模型下，不同物种群的年龄有多大；（二）物种间的系谱或系统发育关系如何；(3)地理分布与形态、分子和交配系统变异水平之间的关系。通过对来自不同地理区域的每个物种提供全面的分类描述，该研究还将为开发用于栽培和生物技术的商业有用的平菇菌株提供基线。

9408347 Vilgalys The oyster mushrooms, genus Pleurotus of the Basidiomycetes, are important as wood degrading fungi, and some species are choice edible mushrooms which are collected or cultivated in many countries. Professor Rytas Vilgalys of Duke University is studying the patterns of species differences in the genus throughout its worldwide distribution. Conventional taxonomic study of morphology and of mating systems is being combined with modern analyses of nuclear ribosomal gene sequences, using numerous samples collected from field trips and from colleagues. Laboratory growth studies will be performed to determine mating systems and the limits of intersterility groups. A simple yet ingenious "spore trapping" technique is also being employed, whereby petri dishes with several tester strains are exposed for 48 hours to the local spore rain and results of hyphal fusion monitored. Concurrent molecular analyses focus on DNA sequence data derived from the worldwide sample of Pleurotus. Results of the studies will help answer several questions relevant to speciation in fungi: (1) how old are different species groups, under a molecular clock model; (2) what are the genealogical or phylogenetic relationships among the species; and (3) what are the relationships between geographic distribution and levels of morphological, molecular, and mating system variability. By providing comprehensive taxonomic descriptions for each species from geographically diverse regions, the study will also provide a baseline for developing commercially useful strains of oyster mushrooms for cultivation and biotechnology.