Diversity And Distribution Pattern Of Lignicolous Freshwater Fungi In Plateau Lakes Of Erhai Basin

Lignicolous freshwater fungi are those fungi that grow on submerged woody debris in freshwater streams,ponds,lakes and tree hollows.This project plans to select four plateau lakes in the Erhai Basin of Yunnan Province,Namely Erhai Lake,Xihu Lake,Cibi Lake and Haixi Lake.In this study,random sampling method was used to collect and isolate lignicolous freshwater fungi from submerged rotting wood,and species identification was carried out by combining morphology and molecular biology.To investigate the diversity and distribution characteristics of lignicolous freshwater fungi in the Erhai Basin(Erhai lake,Xihu Lake,Cibi Lake and Haixi Lake).The results are as follows:1.Three hundred samples were collected from Each of the four lakes,Erhai lake,Xihu Lake,and Haixi Lake,giving a total of 1,200 samples.Microscopically,553 strains were photographed,a total of 293 strains were isolated and purified,and more than 600 molecular sequences were obtained.250 dry samples of lignicolous freshwater fungi were stored(at least two dry samples for each strain).2.A total of 89 species belonging to 5 classes,21 orders,43 families and 61 genera were identified by a combination of morphological and molecular biological methods.The five classes were Agaricomycetes,Dothideomycetes,Eurotiomycetes,Leotiomycetes and Sordariomycetes.Most of them were distributed in Sordariomycetes(7.92%)and Dothideomycetes(6.75%).Among 61 genera,Dictyocheirospora,Clonostachys,Stachybotrys,Lentithecium and Torula had the highest detection rates of1.83%,1.08%,1.00%,0.85% and 0.75%,respectively.3.In this thesis,27 lignicolous freshwater fungi were described in detail,including5 sexual and 22 asexual in ascomycetes.The 27 species described mainly include some species with high frequency and special morphology.4.The species diversity of lignicolous freshwater fungi in Erhai lake,Xihu Lake,Cibi Lake and Haixi Lake is compared.The species richness is the highest in Erhai Lake,followed by Xihu Lake,and the lowest in Haixi Lake(44>26>23>17);Erhai lake had the highest Margalef richness index,Shannon–Wiener index and Simpson dominance index,indicating that Erhai lake had the most abundant species diversity among the four lakes.5.The similarity of lignicolous freshwater fungi communities in four lakes in Erhai Basin was compared,and it was found that the similarity of communities between Erhai lake and Xihu Lake was the highest,and that between Erhai Lake and Haixi Lake was the lowest.6.A new species Neomonodictys aquatica from Erhai Lake was discovered and reported.A phylogenetic tree of Neomonodictys was constructed based on ITS and LSU genes,providing a detailed morphological description of Neomonodictys aquatica and comparing it with N.muriformis,another species of Neomonodictys.7.This thesis aims to reveal the diversity of lignicolous freshwater fungi in Erhai Basin and provide basic research data for the protection of lignicolous freshwater fungi in Erhai Basin.Results not only enriched the diversity of lignicolous freshwater fungi in plateau lakes,but also provided a reference for the distribution characteristics of lignicolous freshwater fungi in static water environment,and provided basic support for the protection and utilization of lignicolous freshwater fungi in plateau lakes.