Analysis Of The Seasonal Changes In Yeast Community Structure And The Influencing Factors In Coastal Water Of Nam Co Lake

Yeasts are widely distributed in various environments in nature,and their community structure and species composition can be used to measure the stability of the habitat ecosystem in which they are found.As the second largest lake on the Tibet,Nam Co Lake special climatic conditions such as high altitude and strong radiation create a special microbial living environment,making it a natural laboratory for studying the diversity of yeast in plateau lakes and isolating and developing special functional yeast strains.In this study,we used the membrane filtration orthotropic culture method to isolate the culturable yeast from the Nam Co Lake in different seasons,and determined the taxonomic status of the isolated yeast strains by r DNA ITS regional sequence analysis,and analyzed the spatial and temporal distribution of the yeast community in Nam Co Lake and its relationship with environmental factors by using bioinformatics and statistical methods.The specific results were as follows:(1)The analysis of the variability of the physicochemical factors of the water bodies in different seasons in Nam Co Lake showed that there were different degrees of significant or highly significant differences among the eight physicochemical factors of the water in different seasons,except for the salinity.(2)A total of 5324 yeast strains belonging to 38 genera and 79 species,including 5 potential new taxa,were isolated from the water samples of Nam Co Lake in three seasons by the culturable method.Mrakia gelida,Vishniacozyma victoriae and Rhodotorula glutinis were the most dominant species of yeast along Nam Co Lake in spring,summer and autumn,respectively,and Nam Co Lake was relatively rich in yeast resources.(3)Non-metric Multidimensional Scaling analysis showed that there were obvious spatial and temporal distribution patterns of yeast community structure in Nam Co Lake,and there were highly significant differences in yeast community structure among regions in all three seasons,and there were also highly significant differences in yeast community structure among the three seasons,among which the differences between spring and other seasons were relatively small,and the differences between summer and autumn were larger.(4)Correlation analysis showed that the yeast diversity of Nam Co Lake coastal was mainly determined by the dominant species community,and the response of yeast diversity to the physicochemical factors of the water body varied among seasons,but was significantly influenced by total dissolved solids,conductivity and salinity in all three seasons.(5)The Canonical Correspondence analysis and Neutral Community Model analysis showed that the water body environmental factors had less influence on the annual horizontal community structure of Saccharomyces cerevisiae in Nam Co Lake,which was only limitedly regulated by the temperature,and the annual horizontal community structure of Saccharomyces cerevisiae in Nam Co Lake was mainly influenced by stochastic processes.(6)The results of ecological niche analysis showed that the yeasts in the water bodies of Namtso in the three seasons were mostly specialized species,with ecological niche in the middle ecological niche and narrow ecological niche,which were less adaptable and more sensitive to environmental changes.The result of the study on yeast along Nam Co Lake used culture research method shows that there are abundant yeast resources in Nam Co Lake,and the development and utilization of functional yeast resources in extreme environment is worthy of in-depth study.