中国西部极端环境中可培养酵母菌多样性特征

Diversity of culturable yeasts in extreme environments of western China

摘要:

目的 探究中国西部极端环境(冰川、盐湖、荒漠等)中可培养酵母菌的物种多样性，并挖掘具有特殊抗逆性的酵母菌株资源。方法 采集极端环境中的多种基质样品，运用8种不同营养梯度的培养基，结合直接涂布与富集培养策略开展菌株分析；采用26S rDNA D1/D2区域序列分析进行菌株鉴定及系统发育分析；通过统计分析，揭示不同生境及培养条件下可培养酵母菌的物种多样性及其群落结构差异。结果 共分离出904株酵母菌，隶属于2门5亚门10纲17目29属77种，其中包含11个潜在新种。担子菌门为绝对优势类群，优势属包括长西氏酵母属(Naganishia)、红酵母属(Rhodotorula)和囊担菌属(Cystobasidium)。不同生境的优势物种存在差异，浅白长西氏酵母(Naganishia albida)和阿德利长西氏酵母(Naganishia adeliensis)在所有极端生境中广泛存在，显示出极强的广谱环境适应性；胶红酵母(Rhodotorula mucilaginosa)和斯洛菲囊担菌(Cystobasidium slooffiae)则是冰川和盐湖环境的优势物种。此外，富集培养和寡营养培养基显著提高了稀有物种的分离效率。结论 中国西部极端环境蕴藏着极为丰富的酵母菌资源。不同极端环境筛选出了独特的优势类群，同时也存在具有多嗜极特征的广适性物种。极端环境不仅是新物种的资源库，也可能是条件致病性酵母菌的潜在环境储库。

Abstract:

Objective To systematically investigate the diversity of culturable yeasts in extreme environments (glaciers, salt lakes, deserts, etc.) of western China and explore yeast resources with special stress resistance traits.Methods Multiple substrate samples were collected from representative extreme environments. Eight media with different nutrient gradients were employed in combination with direct dilution plating and enrichment culture methods for yeast isolation. Strains were identified by 26S rDNA D1/D2 region sequence analysis. Multivariate statistical analysis was carried out to assess species diversity and community structure differences across habitats and culture methods.Results A total of 904 yeast strains were isolated, representing 77 species, 29 genera, 17 orders, 10 classes, 5 subphyla, and 2 phyla, including 11 potential new species. Basidiomycota was the dominant phylum (90.5%), and Naganishia, Rhodotorula, and Cystobasidium were the dominant genera. Distinct dominant species were observed among different habitats. Naganishia adeliensis and Naganishia albida were widely distributed across all investigated extreme environments, indicating strong broad-spectrum environmental adaptability. Rhodotorula mucilaginosa and Cystobasidium slooffiae were dominant species in glaciers and salt lakes. In addition, enrichment culture and oligotrophic media significantly improved the isolation efficiency of rare species.Conclusion Extreme environments in western China harbor remarkably rich yeast resources. While different extreme environments select for unique dominant groups, certain broadly adaptable polyextremophilic species are shared across environments. Extreme environments serve not only as a reservoir of new species but also potentially as an environmental reservoir for opportunistic pathogenic yeasts.