天山一号冰川表面冰尘和底部沉积层中可培养酵母菌系统发育类群的分布及生态生理特征

Phylogeny and diversity of culturable yeasts in supraglacial cryoconite and subglacial sediments of the Glacier No.1 in Tianshan Mountains

摘要:

[目的]揭示乌鲁木齐河源天山1号冰川表面冰尘（CS）和底部沉积层（DS）可培养酵母菌系统发育类群及其结构组成差异，分析低温酵母菌代表菌株之间的生态、生理生化特性。[方法]利用4种培养基分离天山1号冰川可培养酵母菌，采用ITS基因序列分析确定菌种的系统进化地位。对分离菌株的最适生长温度、耐盐性和产酶等生态、生理学特性进行分析。[结果]从冰尘和底部沉积层中共分离出152株酵母菌菌株，通过ITS rRNA基因序列的NCBI比对和Rep-PCR指纹分型，结果表明酵母菌类群包括担子菌门（Basidiomycota）和子囊菌（Ascomycota），分属于14个属26种，其中担子菌门柄锈菌亚门（Pucciniomycotina）88株、伞菌亚门（Agariomycotina）24株，子囊菌门40株，冰川广布酵母菌Vishniacozyma victoriae为优势菌株（占比21.84%）。17种酵母的最适生长温度为15℃、2种为10℃、6种为20℃。25株代表酵母菌株产酶分析显示，产脂肪酶、淀粉酶、蛋白酶菌株分别为11株、11株、5株，6株3种酶都不产。[结论]天山1号冰川冰尘及底部沉积层可培养低温酵母系统发育类群结构存在差异，产低温酶活性高、稳定性好，为今后冰川低温酵母菌的研究提供有价值的数据支持。

Abstract:

[Objective] The objective of this study was to elucidate the phylogenetic group and diversity of structure composition of culturable yeasts isolated from supraglacial cryoconites and subglacial sediments of the Glacier No.1 in Tianshan Mountains and to analyze the physiological and biochemical characteristics of different low temperature yeasts.[Methods] Culturable yeasts were detected on rose Bengal agar (RB), clichloran 18% glycerol agar (DG18), malt extract yeast extract soytone agar (MYP) and yeast-malt extract agar (YMP) media. The phylogenetic position of yeasts was determined by internal transcribed spacer (ITS) gene sequence. The physiological and biochemical tests included optimal growth temperature, salinity tolerance and enzymatic activities.[Results] A total of 152 culturable yeasts were isolated from supraglacial cryoconites and subglacial sediments. The results of National Center of Biotechnology Information (NCBI) alignment of internal transcribed spacer (ITS) rRNA gene sequence and Rep-PCR fingerprinting showed that the yeast groups included Basidiomycota and Ascomycota, belonging to 14 genera and 26 species. Among them, 88 strains were Pucciniomycotina, 24 strains were Agariomycotina, and 40 strains were Ascomycota. Vishniacozyma victoriae was the dominant strain (21.84%). The optimum growth temperature for 17 yeasts was at 15℃, 2 strains at 10℃ and 6 strains at 20℃. The analysis of lipase, protease and amylase activity showed that 11 of the 25 low temperature yeasts produced lipase and 11 produced amylase and 5 produced protease, 6 strains did not produce any enzymes.[Conclusion] The results of this study provide valuable data for the research of community structure and physiological characteristics of cryogenic yeasts in glaciers.