REU: Ultrastructure and Evolution in Auriculariaceous Fungi

在真菌的高级群体（蘑菇，泡球，和亲戚）的进化关系知之甚少。担子菌是高等真菌的两个主要分支之一，其特征是有孢子形成细胞担子，它可以分为两种类型：减数分裂后形成交叉壁或间隔的和没有间隔的。木耳真菌是一类介于子囊菌（假定为担子菌的祖先）和高级担子菌（假定为具有未分裂的担子菌）之间的生物，其担子菌通常在减数分裂后被隔分开。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来研究几组耳真菌的超微结构特征。可能为真菌之间的分类关系提供证据的细胞特征包括减数分裂和有丝分裂细胞分裂，纺锤杆体，担子内的初级和次级间隔以及细胞壁层的分化。从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真菌的更自然的分组。

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.