Evolution in Auriculariaceous Fungi: Structural and Molecular Approaches

9306578担子菌真菌之间的麦克劳克林进化关系尚不清楚。根据担子菌的特性，这些真菌可分为两类。其中一个类群，异担子菌类，似乎介于子囊菌和第二类群之间，子囊菌是担子菌的假定祖先，而第二类群可能是高级担子菌。McLaughlin博士的研究将从超微结构和细胞生物学的角度描述异形担子菌的几个目，以阐明它们的进化和系统学。观察的性状包括纺锤体、核分裂、Speta、细胞骨架、担子和分枝起始。对结构特征的分支分析将为系统发育关系提供指导。通过对结构上检查的物种的大亚基核糖体DNA的分子序列进行分析而获得的系统发育树将被用来检验用形态数据得出的结论。本研究的重点是黑木耳菌目真菌。这种非自然的目包含具有简单或复杂隔膜的物种。简单的隔膜苔藓寄生虫被认为是锈菌(Uredinales)的祖先，将被深入研究。除了上述特征外，还将检查苔藓寄主和寄生虫之间的细胞界面，对苔藓进行接种研究，并将描述苔藓寄生虫的无性阶段。在复杂的分隔耳目中，将与银耳目进行细胞学比较。为了为这项研究和未来的研究获得材料，将在哥斯达黎加收集和培养真菌。

9306578 McLaughlin Evolutionary relationships within the basidiomycete fungi are not understood. These fungi can be divided into two groups based on the characteristics of the basidium. One of these groups, the heterobasidiomycetes, appears to be intermediate between the ascomycetes, the presumed ancestors of the basidiomycetes, and the presumably advanced second group. Research by Dr. McLaughlin will characterize ultrastructurally and cell biologically species in several orders of heterbasidiomycetes to elucidate their evolution and clarify their systematics. The characters to be examined include the spindle pole body, nuclear division, speta, the cytoskeleton, basidia, and branch initiation. Cladistic analysis of the structural characters will provide guidance on phylogenetic relationships. Phylogenetic trees obtained from analysis of molecular sequences of large subunit ribosomal DNA of the species examined structurally will be used to test conclusions reached with morphological data. %%% A major focus of this study will be the Auriculariales fungi. This unnatural order contains species with simple or complex septa. The simple septa moss parasites, which have been postulated to be ancestral to the rust fungi (Uredinales), will be intensively studied. In addition to the characters listed above, the cell interface between the moss host and the parasite will be examined, inoculation studies on mosses will be carried out,a nd asexual stages of the moss parasite will be characterized. In the complex septate Auriculariales cytological comparisons will be made with the Tremellales. To obtain material for this and future studied, fungi will be collected and cultured in Costa Rica.