增温对青藏高原高寒草甸土壤微生物群落的影响

The impact of warming on soil microbial communities in an alpine meadow of the Qinghai⁃Tibet Plateau

揭示气候变暖对土壤微生物多样性及组成是生物多样性和生态系统功能研究的热点。关于不同水平增温如何影响高寒草甸生态系统土壤微生物群落在一定程度上是未知的。本试验在青海玉树州高寒草甸进行不同水平增温试验(W1、W2和W3分别代表增温幅度逐渐增加),基于高通量测序对土壤微生物群落进行了研究。结果表明:(1)气候变暖会显著增加土壤细菌α多样性及β多样性。其中,土壤细菌Shannon指数在W1、W2和W3处理下分别显著增加了2.70%、3.87%和8.73%,而在W3处理下土壤细菌Chao1指数显著增加了17.82%(P<0.05)。(2)细菌的优势菌门均为酸杆菌门和变形菌门,真菌的优势菌门均为子囊菌门和担子菌门。随着温度增加,细菌富集类群的数量增加,而真菌的数量减少。(3)基于PICRUSt及FUNGuild数据库对细菌及真菌进行功能预测,气候变暖后细菌优势潜在代谢功能及真菌生态功能类会发生变化。其中,不同水平增温处理下土壤相对丰度大于2%的功能基因包括Biosynthesis of ansamycins和Biosynthesis of vancomycin group,以及Valine、leucine和isoleucine biosynthesis等生物合成通路。气温升高会增加未分类腐生真菌及丛枝菌根的相对丰度。以上表明,气候变暖后青藏高原高寒草甸土壤微生物群落多样性、组成和功能均会发生变化。

How climate warming impacts soil microbial diversity and composition has long been a focal point in the research area of biodiversity and ecosystem function.However,the extent to which different levels of warming affect soil microbial communities in alpine meadow ecosystems remains largely unknown.We conducted a field experiment with different warming levels(W1,W2 and W3 respectively represented a gradual increase in temperature)in an alpine meadow of Yushu,Qinghai Province,and investigated soil microbial communities using high-throughput sequencing.The results showed that:(1)Climate warming significantly increased soil bacterialα-diversity andβ-diversity.Specifically,the Shannon index of soil bacteria was increased by 2.70%,3.87%,and 8.73%under the W1,W2,and W3 treatments,respectively,while the Chao1 index of soil bacteria was increased significantly by 17.82%under the W3 treatment(P<0.05).(2)Acidobacteria and Proteobacteria were the dominant bacterial phyla,while Ascomycota and Basidiomycota were the dominant fungal phyla.As temperature increased,the abundance of bacterial taxa increased,whereas the fungal population decreased.(3)Functional prediction of bacteria and fungi based on the PICRUSt and FUNGuild databases revealed changes in the potential metabolic functions of bacteria and ecological functions of fungi after climate warming.Functional genes with relative abundances exceeding 2%under different warming levels included Biosynthesis of ansamycins,Biosynthesis of vancomycin group,and Valine,leucine,and isoleucine biosynthesis pathways.Warming increased relative abundances of uncategorized saprotrophic fungi and arbuscular mycorrhizal fungi.These findings demonstrate that climate warming would alter soil microbial community diversity,composition,and function in alpine meadows of the Qinghai-Tibet Plateau.