臺灣地區接合菌卷黴屬(Circinella)及枝柄黴屬(Thamnostylum)之系統分類研究

Abstract

Members of Circinella (Mucoraceae, Mucorales, Mucoromycotina) and Thamnostylum (Syncephalastraceae, Mucorales, Mucoromycotina) are Mucoralean saprophytic fungi. Usually they can be found in soil or on dung of hervbivores and rodents. In this study, 527 soil samples and 433 dung samples were collected from Taiwan, after isolation, purification and identification, totally, 10 Circinella strains were isolated from soil, 21 Circinella strains and 12 Thamnostylum strains were isolated from dung. Five species of Circinella were indentified, including C. minor, C. mucoroides, C. muscae, C. simplex and C. umbellata. One species of Thamnostylum was indentified as T. piriforme. In addition to morphological observation, temperature tests were carried on at 15℃, 20℃, 25℃, 30℃ and 37℃. The result showed that C. minor、C. muscae、C. mucoroides and C. umbellata are thermotolerant fungi, growth temperature up to 37℃, C. simplex are mesophilic fungi what can not grow at 37℃. Molecular biotechnology including polymerase chain reaction (PCR), gene cloning and sequencing were used to obtain the sequences of SSU, LSU-D1/D2 and ITS region (ITS1-5.8S-ITS2) of ribosomal DNA (rDNA). Taxonomic groups generating from molecular analysis of these three gene regions of rDNA are consistent with the groups based on morphological characters. Also, each species can be separated into an individual clade on phylogenetic trees. In addition, C. simplex was not grouped with other Circinella species, it might not be a member of Circinella. Ultimately, a key of the genus Circinella in Taiwan is constructed based on combined data from molecular approach of three sequences of rDNA and the morphological characters. T. piriforme is clustered in one group in phylogenetic tree. It revealed that this is the only one species of Thamnostylum found in Taiwan so far.