Studies On Biodiversity And Molecular Phylogeny Of Freshwater Fungi In Zhejiang Province, P.R. China

Submerged wood from four streams in Zhejiang Province were collected for investigating the biodiversity of freshwater fungi. Collections were made at streams in Baiyunshan Provincial Forest Park (Lishui City), Maoshan National Forest Park (Lishui City, Songyang County), Nine Creeks (Hangzhou City), and Tianmushan Biosphere Reserve (Lin'an City). A total of 173 fungal taxa were recorded, comprising 47 ascomycetes, ten coelomycetes, and 116 hyphomycetes. Most ascomycete species belonged to the Annulatascaceae, Magnaporthaceae, Sordariales incertae sedis, Lophiostomataceae and Massarinaceae. Acrogenospora, Bactrodesmium, Dictyosporium, Ellisembia, Helicosporium, Spirosphaera, Sporoschisma, and Xylomyces were common hyphomycete genera. Inter-stream variations in fungal diversity and species composition were observed, with 59-74 fungal taxa recorded per site. An average of 2.6 taxa per woody substrate occurred in all sites, with a range of 2.37 - 3.36 taxa per sample per site. There were only six species occurring in all streams and all sites had many rare taxa that appeared only once or twice. The highest species diversity was recorded in a stream at Nine Creeks analyzed with parameters of number of species and abundance. The species-area curves from each sampling site did not reach asymptote, indicating the high diversity of each stream and suggesting that more taxa would be sampled with increasing wood sample examination.Four novel hyphomycete taxa were identified from submerged wood in Zhejiang Province including Berkleasmium zhejiangense sp. nov., Cacumisporium uniseptatum sp. nov., Dictyosporium zhejiangensis sp. nov., and Sporidesmiopsis zhejiangensis sp. nov. which are described. Morphological similarities and differences between the taxa and other similar species are discussed. Several common freshwater species were examined in this study. New records and interesting freshwater fungi from the Zhejiang collections are also documented and discussed. Molecular phylogenies of some freshwater fungi obtained from submerged wood in Zhejiang Province combined with available ITS or 28S rDNA sequences form GenBank were evaluated. The ITS regions were used to infer phylogenetic relationship of new species Dictyosporium zhejiangensis sp. nov. with other species in the genus Dictyosporium. Evolutionary relationship among different species within the genus Dictyosporium was investigated based on ITS-5.8S rDNA gene sequences. Results indicated that Dictyosporium is monophyletic and 12 taxa of Dictyosporium clustered into two clades. Dictyosporium zhejiangensis sp. nov. formed a clade together with Dictyosporium species which have flattened conidia bearing appendages.The 28S (LSU, large subunit) is moderately conserved but provides sufficient variation to study relationships/placement at the generic level. The phylogenetic relationships/placement of the genera Berkleasmium, Sporoschisma, and one unidentified hyphomycete among sexual ascomycetes based on 28S rDNA were examined. Phylogenies revealed that Berkleasmium species are not monophyletic and have affinities with the Pleosporales. In addition, Berkleasmium zhejiangense sp. nov. is closely related to the Sporormiaceae (Pleosporales).The analysis of 28S rDNA sequences successfully verified the teleomorph-anamorph connection between Melanochaeta and Sporoschisma. Sporoschisma species derived from this collection formed a strong monophyletic group with its teleomorph Melanochaeta with highly supported by bootstrap value of 100%. An unidentified hyphomycete, in addition, had phylogenetic affinity with Ascotaiwania species by 28S rDNA sequences analysis.