Study On The Diversity Of Yeast In Qinghai-tibet Plateau

Yeast is a kind of tiny single-celled fungus,which is widely distributed in soil,air,aquatic environment,plant surface,animal intestine,skin and other environments.Known as the "Roof of the World" and "Third Pole",the Qinghai-Tibet Plateau has high altitude,high drop,low latitude,complex and diverse climate,and rich and diverse ecological types,which not only promotes the accelerated variation and differentiation of biological groups in the region,Has formed many endemic species adapted to the unique environment of the plateau,and also made the Qinghai-Tibet Plateau one of the most abundant and unique regions in the world.However,there are few reports on the species diversity and distribution of yeast in the Qinghai-Tibet Plateau.In order to understand the yeast community structure and species diversity and differences in different habitats on the Qinghai-Tibet Plateau,we analyzed 6 different geographical locations on the Qinghai-Tibet Plateau.1200 samples of different substrates from,a total of 3030 yeast strains were isolated.The taxonomic status of these strains has been determined through morphological observation,physiological and biochemical experiments and molecular identification.A preliminary understanding of the species composition and diversity of yeasts in the Qinghai-Tibet Plateau has been made,and the succession and succession of yeast communities in the plateau environment has been further analyzed.The impact of species diversity.In addition,some strains resistant to hyperosmosis and high sugar were isolated,and their species composition was analyzed to provide strain materials for the improvement and application of industrial strains in the future.The main experimental results are as follows:1.1695 strains with representative colony characteristics were selected from 3030 yeast strains,and the ITS region sequence of the ribosomal r RNA of these strains was determined.After the sequence was Blasted in the NCBI database,the similarity with the model strain was used and MEGA7 was used.0software does a phylogenetic tree analysis of near-source species,and it is estimated that these 1695 yeasts are distributed in 167 genera and 410 species,of which 110 are ascomycetes,300 are basidiomycetes,and there are about 10 suspected new strains.2.Morphological description and physiological and biochemical tests were performed on some pseudo-new species of yeast,and it was found that the traits of some strains were different from those described in molecularly identified model species,especially in terms of temperature,most strains could only be at30? Growth indicates that most of the yeast populations on the Qinghai-Tibet Plateau belong to low-temperature-tolerant yeasts.3.Analyze the yeast species composition,yeast species distribution,and habitat environment specificity in the Qinghai-Tibet Plateau.The results show that the Qinghai-Tibet Plateau has significant yeast diversity.Especially in Linzhi,Tibet,the number and types of yeast species are very high.proportion.The composition and abundance of yeasts in samples from different regions are different,but Curvibasidium,Cryptococcus,Candida,Aureobasidium,Cystofilobasidium,Debaryomyces,Metschnikowia,Mrakia,Naganishia,Rhodotorula,Solicoccozyma were all isolated;At different spatial levels,the distribution of yeasts is also quite different.At relatively low altitudes,the diversity and abundance of yeasts are relatively high.This may be because low altitudes provide a superior environment for the growth of yeasts.The genera Aureobasidium,Cystofilobasidium,Curvibasidium and Metschnikowia are widely distributed in high altitude areas,which may be related to the psychrophilicity of these yeasts.There are differences in the composition of wild yeast communities in different habitats in Tibet.The abundance and diversity of psychrophilic yeast are relatively high.Importantly,there is almost no geographical clustering of any yeast species in the isolated yeast strains.This study on the diversity of wild cultivable yeast in Tibet will provide certain data support for further exploring the species diversity and sources of microorganisms on the Qinghai-Tibet Plateau in my country,and lay the foundation for the future development and utilization of yeast strains.4.In the analysis of the yeast diversity of the Qinghai-Tibet Plateau,it was found that about 10 strains were different from the close-source yeast species currently reported at home and abroad.The differences between these strains in the ITS region and the recent model strains were all above 2%.Therefore,we treat these strains as suspected new species,and describe and define new species for some of them.5.The analysis of high-sugar-tolerant yeast groups showed that only a small number of yeast strains grew under 50% glucose and high-sugar medium.