Comparative Study Of The Community Structure Of Yeasts In Different Habitats Of The Glacier No.1 In The Tianshan Mountains

Glacial various habitats are known global reservoirs for cold-adapted microorganisms.Yeasts are ubiquitous microorganisms and Cold-adapted yeasts biodiversity of worldwide cold habitats has attracted the interest of an in creasing number of biologists.The aim of this investigation was to assess the occurrence and biodiversity of cold-adapted yeasts in glacial superficial air samples from the glaciers No.1 in Tianshan Mountain(northwestern China),and study their growth characteristics.Different habitats particularly airborne yeasts from the Glacier No.1 in Tianshan Mountain were investigated to reveal their species diversity and analyze the influence of environment factors on yeast diversity.A total of 2016 yeasts were recovered.For the present study,air samples were collected from Tianshan No.1 glacier,a well-known cold-based glacier,located in Tianshan Mountains(86°48?E,43°06?N)on the region of central Asia.It is 2.4 km long and the area of glacier is 1.68 km~2.The average annual temperature is around 5?.Supraglacial habitat samples were collected on the surface of the west branch of glacier at different sites at altitudes of 3950?4090 m.Isolation and purification of Supraglacial culturable yeast using RDBC,DG,MYP and MYP5 media,And colonies were selected for isolation on the basis of morphology,The isolates were preliminarily typed using a series of conventional phenotypic tests,macroscopic and microscopic morphology.Growth characteristics analysis of the cultures grown at six different temperatures(4,10,18,25,30 and 37?)was also done.Taxonomic position of the strains was defined according to their Internal Transcribed Spacer(ITS)sequence analysis and the phylogenetic relationships of the cultures,and then the composition,distribution,and diversity of the different source yeasts were analyzed in detail.The yeast community from BA was most diversity than the yeast community from BC,BW,SN,BB.The dominance index was similar for both substrates.A total of 60 taxa from different habitats and 60 from MA were identified,and only 14 were common to both positions.In total,2016 cold-adapted yeasts were isolated identified by from the surface air,superficial cryoconite,superficial melting water,surface snow cover,superficial ice and different plants of the Glacier No.1.The results of NCBI blast of ITS rRNA gene sequence and MSP–PCR fingerprinting showed that the yeast groups belonged to 60 species of 22 genera(Cryptococcus?Cystobasidium?Cystofilobasidium?Dioszegia?Filobasidium?Glaciozyma?Leucosporidium?Mrakia?Holtermanniella?Naganishia?Papiliotrema?Phenoliferia?Schizonella?Vishniacozyma?Rhodotorula?Rhodosporidium?Aureobasidium?Candida?Metschnikowia?Microbotryum?Pichia and Thelebolus).Among them,the most dominant species was Vishniacozyma victoriae(18.70%)frequency of occurrence,followed by Cystofilobasidium macerans with a 8.28%.48 strains of the 60 representative yeasts stopped growing at 37?,which called facultative psychrophiles;12 strains grew at a temperature ranging from 0?to 25?and were obligate psychrophiles.The classification in facultative and obligate yeasts has been established according to their growth temperature requirements.Diversity,richness and dominance of culturable yeasts,were quantified using Shannon,Simpson's and Chao indices.These results are promising for the developing of biological products based on cold-adapted yeasts in cold-temperate regions.This study in biodiversity,presenting physiological and molecular characterization of psychrotolerant yeast strains isolated from the air of Tianshan No.1 Glacier,contributes to a better understanding of the microbial ecology of this unique cold-based glacier ecosystem.The yeast community from Tianshan No.1 glacier showed a high species richness and a uniform distribution of taxa between lower and higher collection points.These result indicate that cold-yeasts inhabit the air of the mountain glaciers have a community structure that is unique and have a high tolerance to the harsh conditions that enables them to adapt to the harsh environmental conditions.The diversity of low temperature resistant yeasts in the air on the surface of Tianshan No.1 Glacier is rich,which is suitable for carrying out community structure and microbial ecology research.