广西桂林新村屯洞穴细菌群落的生境特异性及网络分析  

Habitat specificity and co-occurrence network of bacterial communities in the Xincuntun Cave, Guilin, Guangxi

作　　者：曹静 程晓钰 曾智霖 杨梓琪 刘晓燕 王红梅[1,2] 马丽媛[1] 鲁小璐 苏春田 黄奇波[3] Jing Cao;Xiaoyu Cheng;Zhilin Zeng;Ziqi Yang;Xiaoyan Liu;Hongmei Wang;Liyuan Ma;Xiaolu Lu;Chuntian Su;Qibo Huang(School of Environmental Studies,China University of Geosciences,Wuhan 430074,China;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Wuhan 430074,China;Key Laboratory of Karst Dynamics,Ministry of Natural Resources,Institute of Karst Geology,Chinese Academy of Geological Sciences,Guilin 541004,China)

机构地区：[1]中国地质大学(武汉)环境学院,武汉430074 [2]中国地质大学(武汉),生物地质与环境地质国家重点实验室,武汉430074 [3]中国地质科学院岩溶地质研究所,自然资源部岩溶动力学重点实验室,桂林541004

出　　处：《科学通报》2021年第31期4003-4016,共14页Chinese Science Bulletin

基　　金：国家自然科学基金(91951208);广西自然科学基金(2020GXNSFAA297025);中国地质调查局地质调查项目(DD20190343)资助。

摘　　要：洞穴是研究深地生物圈的天然实验室,对认识深地生物圈微生物多样性及群落分布特征至关重要.以我国岩溶最为发育的广西桂林市为研究区,对新村屯洞穴内不同小生境进行了系统采样,通过Illumina高通量测序和生物信息学的分析,发现洞穴中细菌群落以放线菌门(Actinobacteria)和变形菌门(Proteobacteria)占优势,不同生境间细菌群落α多样性存在显著差异,以洞穴上覆土壤α多样性最高,洞穴内微生物席α多样性最低.洞穴内细菌组成按生境聚类,不同生境具有独自的指示类群,干燥石笋表面生物膜指示属为Nitrospira和Polycyclovoran;上覆土壤、微生物席、沉积物和风化结皮的指示属分别为Candidatus Udaeobacter、Vicinamibacter、Bacillus和Longimicrobium,显示出洞穴细菌群落的生境特异性.冗余分析结果证实pH和TOC(total organic carbon)对微生物群落的空间分布具有重要影响.共现性网络分析表明,洞穴细菌群落网络高度模块化,γ-变形菌纲(Gammaproteobacteria)、Candidatus Udaeobacter和嗜热油菌纲(Thermoleophilia)为排名前三的关键种,对维持细菌网络的稳定性起着重要作用.共现性网络节点之间以正相关连接占主导,表明微生物主要通过相互协作以共同抵抗洞穴中的极端条件.这些结果揭示了新村屯洞穴生态系统中微生物群落的生境特异性和微生物之间的相互作用,提升了人们对洞穴生态系统这一陆地深地生物圈的认识.Although karst systems comprise approximately 5%-20% of the Earth’s ice-free land surface, only 10% of them have so far been explored. Karst caves are important components of karst systems and represent one of the most unique and poorly understood ecosystems on Earth. They are extreme environments in terms of nutrition deficiency, permanent darkness, and isolation from other ecosystems, and serve as a natural laboratory to study the deep biosphere. Caves are also ideal places to discover microbial dark matter such as microbial biodiversity and novel metabolic pathways and metabolites.Microorganisms in caves have been demonstrated to be involved in the dissolution and formation of minerals,biogeochemical cycles, and degradation of organic matter and thus have a fundamental role in sustaining the cave ecosystems. However, knowledge about microbial distribution, diversity, potential functions, and interactions in subsurface caves has remained limited to date particularly in different niches, which limits the utilization of microbial resources and hampers our understanding of biogeochemical processes in the deep biosphere. To address these issues, bacterial communities from seven different niches including cave wall, weathered crust, loose sediments, biofilms from the wet surface of stalagmite, biofilms from the dry surface of stalagmite, microbial mat on rock surface, and overlying soils in the Xincuntun Cave, Southwest China, were investigated via high-throughput sequencing and bioinformatics. Alpha diversities of bacterial communities significantly differed from one niche to the other. Specifically, bacterial diversity was the highest in the overlying soil, followed by those in weathering crust, sediments, wet surface of stalagmite, cave wall, dry surface of stalagmite, and microbial mat. Bacterial communities were dominated by Actinobacteria and Proteobacteria and showed high specificity for their niches as indicated by principal coordinates analysis(PCo A) and bacterial indicator groups identified by the linea

关 键 词：细菌群落 共现性网络分析 深地生物圈 喀斯特洞穴 生境特异性 

分 类 号：Q938[生物学—微生物学]