Abstract

Pyrenomycete species of Cercophora and Podospora are common on the dung of herbivores. Schizothecium was differentiated from Podospora based on morphological characters and further supported by molecular phylogenetic analyses. This study focused on phylogenetic relationships of Cercophora and Podospora including species of Schizothecium. Two gene sequences, ribosomal DNA internal transcribed spacers (ITS/5.8S rDNA) and a fragment of glyceraldehyde-3-phosphate dehydrogenase (GPD), were amplified and examined using maximum-parsimony and Bayesian analyses. In all analyses, Cercophora and Podospora were found to be polyphyletic, each consisting of a group of morphologically heterogeneous and phylogenetically distant species. Species of Schizothecium were all located in one clade and two Cercophora species with similar perithecial hair structures formed a sister group to it. The recognition of Shizotheium is reconfirmed. The phylogeny indicated a relevant relationship with the perithecial morphology in the Lasiosphariaceae.

中文摘要

尾柄孢殼屬 (Cercophora) 和柄孢殼屬 (Podospora) 均為在草食性動物糞便上的常見真菌。以往依據形態特徵，將柄孢殼屬另分出一個裂殼屬 (Schizothecium)，近來以分子親緣分析，也證實這屬的成立。本研究是以細胞核DNA分子序列來探討尾柄孢殼屬和柄孢殼屬包含裂殼屬成員間的親緣關係。先以聚合酶鏈結增幅反應 (polymerase chain reaction, PCR)的方法，增幅目標菌種的ITS/5.8S rDNA及GPD (甘油醛-3-磷酸脫氫酶；glyceraldehyde-3-phosphate dehydrogenase) 基因序列。並以ITS/5.8S rDNA 與GPD序列，利用最大簡約法 (maximum parsimony) 與貝貽理論 (Bayesian Inference) 找到最佳的親緣關係樹。由分析結果顯示，尾柄孢殼屬和柄孢殼屬均為多親緣性(polyphyletic)，裂殼屬成員與柄孢殼屬分開另成一群，並與具有相似子囊殼毛形態的二個尾柄孢殼屬成員為姐妹群，本研究認同以往的研究，裂殼屬可獨立成一屬，而親緣分析顯示子囊殼的形態在毛球殼科中是具有關連性的。

Keyword: Cercophora, Lasiosphaeriaceae, Phylogeny, Podospora, Schizothecium, Systematics.