| Aquatic fungi are defined in an ecological sense rather than a taxonomic sense for this fungi which the whole or part of their life cycle rely on freshwater, with high diversity. We mainly focus on the aquatic Ascomycete and its anamorph in this study. Aquatic fungi play an important role in the ecosystem, it can decompose organic substrata in freshwater, mainly include the plant residues, organic material which have rich lignin and cellulose and their mycelium are involved into the food web when grazed by animals.Aquatic fungi as a nearly untapped natural resources, has a great potential value in use and research, especially the researchers paying more and more attentions on the metabolites produced by aquatic fungi.Yunnan is one of province with the highest biodiversity in China, but there have a few of research on aquatic fungi especially in Erhai lake and Cangshan mountain National Nature Reserve.In this research, we chosed Erhai Lake and Lingquan & Heilong streams in Cangshan Mountain as the research site, bait method is used to isolate the aquatic fungi from decaying wood in four seasons in Erhai Lake, identified the fungi to genus or species level under the phylogeny analyses and morphological characteristics. The dry specimens and pure cultures are deposited in Dali University for future work.The relationship between diversity of aquatic fungi and water quality and seasonal variation are provided. Branches of Salix matsudana f. tortuosa and Alnus tinctoria sargs were used for baiting the fungi in Lake Erhai to provide the relationship of the different plants and fungal diversity. In addition, descriptions and illustrations are provided for the five species of Minimelanolocus in Chaetothyriales based on the multi-gene phylogeny analysis, and provided a natural classification for this genus. The results were as follows:1. 239 isolates were found out during our study on diversity of aquatic fungi in Erhai Lake, 39 genera including 44 species of aquatic Ascomycetes and its anamorph were identified. Compared the fungal community and diversity in Erhai Lake, Dianchi and Fuxian Lake, the results showed that Erhai Lake have the highest fungal diversity, Fuxian Lake took second place, last one is Dianchi with the Diversity index is 3.84>3.81>3.37.2. The correlation study between the season and fungal diversity of aquatic fungi showed that, the temperature in September is highest(21.1°C) and fungal diversity also is the highest(H′ = 3.26, D = 0.95), the temperature in December is lowest(13.2 °C) and diversity also is the lowest(H′ = 1.43, D = 0.68). The results show that temperature had a great influence on aquatic fungal diversity.3. We also Compared the fungal community on Alnus tinctoria and Salix matsudana at June and December, the data showed there have a highly similarity of fungal community between these two plants and the aquatic fungi diversity on Alnus tinctoria is higher than Salix matsudana(H′ = 3.33 vs 3.30,D = 0.954 vs 0.952), may be related to the A. tinctoria is more softer than S. matsudana so it is more easy becoming decayed in this case.4. In order to find out the fungal diversity in Erhai Lake, we provided the photoplates and descriptions of 7 Ascomycetes, 2 Ceolomycetes, and 34 Hyphomycetes in this study, more and more aquatic fungi will be identified after we got the molecular data in future, this will provide basical database for the studies on the aquatic fungi in Erhai Lake.5. Phylogenetic trees of the order Chaetothyriales were established in this study. The characters of all the known species in the genus Minimelanolocus are summarized(including 4 new species). |
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