| Summary: | 碩士 === 國立中興大學 === 生命科學系 === 93 === Coprophilous Pyrenomycetes of Cercophora and Podospora (Lasiosphaeriaceae) are usually grown on dung of herbivores. Two species of Cercophora and eighteen species of Podospora have been previously reported from Taiwan. The genus Podospora is characterized by ascospores with hyaline pedicel and gelatinous appendages. Cercophora Fuckel has hyaline, cylindrical ascospore with a swollen, pigmented head. Based on the morphology of perithecia and spore development, Lundqvist (1972) divided Podospora into two genera: Podospora and Schizothecium. There is no further research in the phylogenetic relationships of Cercophora and Podopsora.
To investigate biodiversity and molecular phylogeny of Cercophora and Podospora from Taiwan, speciemans were collected from dung of herbivores by using moist chamber method and cultures were isolated. Crude genomic DNA from each pure strain was isolated. The ribosomal DNA internal transcribed spacers (ITS/5.8S rDNA), 28S ribosomal DNA gene, and the fragment of glyceraldehyde-3-phosphate dehydrogenase (GPD) sequences were amplified by polymerase chain reaction (PCR). ITS2 secondary structures of Cercophora and Podospora were constructed by rule of minimum free energy that were used to guide our sequences alignment. The concatenated sequences of ITS/5.8S, 28S rDNA, and GPD were used to construct phylogenetic trees of Cercophora and Podopsora species.
One new species and seven new records were discovered during this study. P. multipilosa is a new species. Cercophora acanthigera, C. coprophila, C. gossypina, C. tuberculata, Podospora araneosa, P. immersa, and P. pleiospora are new records in Taiwan. Description and illustration of these species, cultural characteristics of some species and two keys to six species of Cercophora and the twenty-two Podospora species from Taiwan are provided.
A four-arm model of ITS2 sequences in Cercophora and Podospora were predicted by the rule of Minimum free energy. The arm 3 is the longest and the most variable in length. The secondary structure is congruent with their morphological characters such as having large tufted hairs composed of swollen cells in Cercophora and Podospora. The results in the phylogenetic analysis suggest that Cercophora and Podospora are composed a monophyletic group, but not Cercophora, Podospora, and Schizothecium respectively. The revision of these genera is necessary in the future.
|
|---|
