Diversity And Enviromental Impact Factors Studies On Aquatic Ascomycetes And Their Asexual Morph In Northwestern Yunnan, China

Aquatic fungi are those fungi that the whole or part of their life cycle rely on aquatic habitats,is a special ecological group with highly diversity.Aquatic fungi play an important role on organic degradation and nutrient cycling in aquatic ecosystem,these fungi mainly can decompose organic substrata in freshwater,include the plant residues,organic material which have rich lignin and cellulose and their mycelium are involved into the food web when grazed by aquatic animals.Researches on freshwater fungi were started from 1942 and mostly focus on the fungal diversity.There have no more systematic research on the distribution pattern and its influencing factors.North-western of Yunnan Province is one of the biodiversity hotspots around the world.In our study,we did investigations on the fungal communities,diversity,distribution pattern and its influencing factors of freshwater fungi in this region.New species and fungal resources which have potential application value were found out.Submerged decaying wood samples and water samples were collected from Dulong River,Nujiang River,Lancang River,Jinsha River and Heilong Stream in Cangshan mountain.Altitude,water temperature,longitude and latitude,PH were recorded during the collection trip.Relationship of fungal communities,distribution pattern and its influencing factors of freshwater fungi were carried out by using multiple factors analysis.Phylogeny analysis were conducted based on the ITS,18S,28S sequences data to make the taxonomy system of freshwater fungi more close to the natural system.The mainly results were as following:1.Totally,1495 submerged decaying wood samples were collected from Langcang River,Nujiang River,Jinsha River,Dulong River and Heilong Stream in Cangshan Mountain in the north-western of Yunnan Province.The samples were processed and examined in the lab,1502 specimens were deposited in herbaria of Dali University.Obtained 1502 pure cultures,deposited in Dali University Culture Collection(DLUCC).Got 890 sequences strains including ITS,LSU,SSU,TEF1 ?and RPB2,60 sequences were submitted to GenBank.337 species of freshwater ascomycetes out of 167 genera and 17 species of nemotade-trapping fungi out of 4 genera were identified based on phylogeny and morphological characters.Original photoplates and descriptions of 87 species of aquatic asexual fungi were provided.2.Introduced a new family Distoseptisporaceae,3 new genera Neotorula,Distoseptispora,Pseudosporidesmium,14 new speices Dendryphion aquaticum,D.submersum,Distoseptispora fluminicola,D.aquatica.,Kirschsteiniothelia submerse,Neotorula aquatica,Sporidesmium aquaticum,S.Submersum,S.fluminicolum,Phragmocephala garethjonesii,Minimelanolocus asiaticus,M.aquaticus and M.melanicus,Lentithecium cangshanense,Descriptions,photoplates and phylogeny trees of the species in the genera Curvularia,Phragmocephala,Neotorula,Distoseptispora,Pseudosporidesmium,Dendryphion,Kirschsteiniothelia,Sporidesmium,and Torula were provided.3.Did Index simulation analysis,Diversity index,Analysis of similarity based on the temperature,climate,vegetation types,altitude,the physical and chemical properties,the result showed that the fungal diversity is mostly related to the altitude and the temperature.The fungal diversity at the Mid-Low altitude is richest,increase with increasing of elevation,the fungal diversity is reduced.There was no apparent association between fungal diversity and Ph.Because the rind of submerged wood were fall off,we can't identified the plants to species,so can't find out the relationship between freshwater fungi and the plants.4.There have only one nematode-trapping fungi reported from submerged decaying wood previously,but we got many in this research.Some morphological characters of nematode-trapping fungi from aquatic habitats is obviously different with terrestrial species,such as did not formed trap,same species have different morphological characters,the results shown that the nematode-trapping fungi from aquatic habitats should be a good materials to do the origination and evolution,ecological adaptation research on these fungi.5.The distribution pattern of freshwater fungi in northwestern Yunnan:The fungal diversity at the low altitude is richer than high altitude,dominant taxa are different at High-Middle-Low altitude,fungal diversity of western low latitude river is higher than eastern high latitude river,there have different endemic species at different rivers.Cosmopolitan genus Sporidesmium is also widely distributed in the north-western of Yunnan Province.Furthermore,the genera Minimelanolocus,Dactylaria,Ellisembia,Helicomyces,Periconia,Phaeoisaria,Sporidesmiella are also widely distributed in our research regions,the most popular genus appeared to be Minimelanolocus.The fungal diversity of Dulong river is most abundant,second is Heilong Stream in Cangshan Mountain,Lancang River with the lowest fungal diversity.