Dissertation Research: Phylogeny in the Genus Omphalina (Basidiomycota Agaricales) and the Evolutionary Consequences of Mutualism

[332 . 1828]有人认为，远亲生物之间的共生关系可能导致新门的产生，并可能有助于植物在陆地上的殖民。支持这些假设的论点的高度推测性内容导致了许多争议。本项目将通过研究一组担子菌属真菌及其亲缘种，对互惠共生的进化作用进行实证研究。这个群体非常适合于互惠关系的进化研究，因为它包括密切相关的腐生物种（即非互惠物种）和互惠物种（与藻类结合形成地衣的物种），这表明向互惠状态的过渡可能是相对较近的（Lutzoni和Vilgalys， 1993）。在这项研究中，形态学和分子特征将被用来推断Omphalina种之间的系统发育或相互关系，并研究该属与其他类群的关系。这些初步结果将用于检验有关向共生/地衣形成的生活方式转变的特征的假设。这个模型系统将解决有关不同生物（在这个例子中，真菌与藻类形成地衣）可能产生新的生命形式的共生关系的重要问题。

9321828 Vilgalys It has been suggested that mutualistic associations between distantly related organisms can lead to the beginning of new phyla and may have been instrumental in the colonization of land by plants. The highly speculative content of the arguments supporting these hypotheses has led to much controversy. This project will undertake empirical studies of the evolutionary role of mutualism by studying a group of basidiomycete fungi, species in the genus Omphalina and its relatives. This group is well suited for evolutionary studies of mutualistic associations because it includes closely related saprophytic (i.e. non-mutualistic) and mutualistic species (those associating with algae to form lichens), suggesting that the transition to a mutualistic state might be relatively recent (Lutzoni and Vilgalys, 1993). In this study, both morphological and molecular characters will be utilized to infer the phylogeny or relationships of species of Omphalina to each other, as well as investigating the relationships of this genus to other groups. These first results will be utilized to test hypotheses concerning features involved in changing to a mutualistic/lichen forming life style. %%% This model system will address important questions concerning the possible mutualistic association of different organisms (in this case, fungi with algae to form lichens) leading to new life forms.