Diversity And Phylogenetic Systematics Studies On Aquatic Ascomycetes And Their Asexual Morph In Cangshan Mountain

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 aquatic habitats.Aquatic fungi with wide distribution and highly diversity can decompose organic substrata in aquatic habitats,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 and also can produce metabolites which have antimicrobial activities or nematicidal activities.Ingold is the first researcher and reported the freshwater fungi at 1941 and later more and more mycologists such as Shearer,Hyde and Tsui did more researches on aquatic fungi.Presently,there are about 3000 species of fungi were reported from aquatic habitats all over the world and only 1000 species were reported in China.Our knowledge of aquatic fungi in China are poorly and further more researches of aquatic fungi from China is imperatively needed in the future,especially the northwest of Yunnan Province,one of the biodiversity hotspots.In this study,we investigated the aquatic fungal diversity in Cangshan Mountain.Submerged wood were collected from different sites in Cangshan Mountain via Heilong stream,Lingquan stream,Wanhua stream,Qingshui river,Longba river,Heihui River and Huadianba meadow and returned to the laboratory in plastic bags.The samples were incubated in plastic boxes lined with moistened tissue paper at room temperature for one week and examined under microscope.Single spore isolation were made to obtain pure cultures.The cultures and specimens are deposited in Dali University.Fungal species were identified based on morphology and phylogenetic analyses and also analyzed the relationships of aquatic fungal diversity with seasonal characteristics and artificial factors.Carried out the aquatic fungal diversity of Cangshan Mountain,the results are as following:1.Totally 880 submerged decaying wood were collected and obtained 854 cultures.108 genera,201 species with 20 new taxa were identified according the morphological characters and phylogenetic analyses.The Shannon's diversity index H' of eastern slope,western slope and Huadianba meadow of Cangshan Mountain are: 3.82,4.16,4.33.2.Compared the fungal diversity between Heilong stream,Wanhua stream and Lingquan stream,the Shannon's diversity index H' of each stream are: 3.56,3.73,4.22,the results showed that Heilong stream's fungal diversity is the best.3.Investigated the resources of aquatic hyphomycetous fungi in Heilong stream during dry and rainy season.Shannon's diversity index H' of dry season(3.67)is obviously higher than rainy season(2.32).4.Index of similarity of aquatic fungi in Cangshan Mountain was calculated using Sorensen's formula to determine the similarity in species occurrences,the similarity values of eastern slope and western slope of Cangshan Mountain is 0.69,eastern slope and Huadianba meadow is 0.64,and of western slope and Huadianba meadow is 0.67.The results showed the fungal community structures differences of these regions are unconspicuous.5.Provided phylogenetic tree for the family Dictyosporaceae and introduced two new species for the genus Dictycheirospora,compared the morphological and phylogeny of Dictycheirospora rotunda(type species),D.aquatica and D.garethjonesii.6.Provided the illustrations and descriptions for 32 species of aquatic hyphomycetous fungi and 8 species of aquatic ascomycetous fungi.