REU: Ultrastructure and Evolution in Auriculariaceous Fungi

高级真菌类群(蘑菇、马鞭菌和近缘真菌)之间的进化关系知之甚少。担子菌是高等真菌的两大分支之一，其特征是担子，即形成孢子的细胞，可分为两种类型：减数分裂后形成横壁或隔膜的担子和不形成隔膜的担子。黑木耳真菌是一类介于担子菌祖先子囊菌和高级担子菌之间的生物，其担子通常在减数分裂后由隔膜分裂而成，担子是不分离的。明尼苏达大学的麦克劳克林博士将使用强大的电子显微镜技术研究几组耳木科真菌的超微结构特征。可能产生真菌分类关系证据的细胞特征包括减数分裂和有丝分裂细胞分裂、纺锤体极体、担子内的初级和次级隔膜以及细胞壁层的分化。细胞结构和功能的这几个方面的证据的相关性应该有助于确定介于子囊菌和担子菌之间的更自然的真菌分类。

Evolutionary relationships within the advanced groups of fungi (mushrooms, puffballs, and relatives) are poorly understood. The basidiomycetes, one of two major divisions of higher fungi, are characterized by the basidium, the spore- forming cell, which can be of two types: those which form cross walls or septa after meiosis and those without septa. The auriculariaceous fungi, whose basidia typically become divided by septa after meiosis, are a group of organisms with characteristics intermediate between the ascomycetes, the presumed ancestors of the basidiomycetes, and the presumably advanced basidiomycetes, with undivided basidia. Dr. McLaughlin of the University of Minnesota will use powerful electron- microscopic techniques to study ultrastructural features in several groups of auriculariaceous fungi. Cellular features that are likely to yield evidence of taxonomic relationships among fungi include aspects of meiotic and mitotic cell-division, the spindle pole body, primary and secondary septa within basidia, and the differentiation of cell- wall layers. The correlation of evidence from these several aspects of cellular structure and function should help determine a more natural grouping of the fungi intermediate between the ascomycetes and basidiomycetes.