基于宏基因组分析纳帕海高原湿地微生物及其碳氮代谢多样性

Metagenomic analysis of the diversity of microbes in the Napahai plateau wetland and their carbon and nitrogen metabolisms

摘要:

由于地理位置特殊和生态系统类型的复杂多样性，高原湿地在水源供给、温室气体调节、生物多样性保护等方面具有不可忽视的生态作用。纳帕海高原湿地是特殊的低纬度高海拔湿地类型，目前关于其微生物多样性的研究较少。文中基于宏基因组学方法对纳帕海高原湿地微生物的基因组进行测序，在细菌域中鉴定出184个门、3 262个属、24 260个种；在古菌域中检测到13个门、32个属；在真菌域中共有13个门、47个属。土壤和水体的物种多样性具有明显差异：在门水平上，土壤中酸杆菌门、变形菌门和放线菌门为优势菌门，水体则以变形菌门和拟杆菌门为主。通过宏基因组分析获得纳帕海微生物群落的多样性数据，并对高原湿地中固碳途径和氮代谢途径进行了初步分析。研究表明碳、氮代谢基因丰度较高，湿地微生物固碳途径主要以卡尔文循环、还原性三羧酸循环和3-羟基丙酸循环为主，变形菌门、绿弯菌门、泉古菌门为主要固碳菌群；对于氮循环，水中以固氮和异化硝酸盐还原过程为主，土壤则以硝化和反硝化过程为主，变形菌门、硝化螺旋菌门、疣微菌门、放线菌门、奇古菌门和广古菌门的微生物为氮循环的主要贡献者。本研究揭示的纳帕海高原湿地微生物多样性，为湿地环境的综合治理和保护提供了新的知识。

Abstract:

Due to the special geographical location and the complex ecosystem types, plateau wetlands play important ecological roles in water supply, greenhouse gas regulation and biodiversity preservation. Napahai plateau wetland is a special wetland type with low latitude and high altitude, and its microbial diversity was rarely studied. The diversity of microbial communities in the Napahai plateau wetland was analyzed using metagenomics method. Among the microbes detected, 184 phyla, 3 262 genera and 24 260 species belong to the bacterial domain, 13 phyla and 32 genera belong to the archaeal domain, and 13 phyla and 47 genera belong to the fungal domain. Significant differences in species diversity between soil and water were observed. Acidobacteria, Proteobacteria and Actinobacteria were dominant phyla in soil, while Proteobacteria and Bacteroides were dominant phyla in water. Since the carbon and nitrogen metabolism genes were abundant, the pathways of carbon fixation and nitrogen metabolism were analyzed. Calvin cycle, reductive tricarboxylic acid cycle and 3-hydroxypropionic acid cycle were the main carbon fixation pathways, while Proteobacteria, Chloroflexi, and Crenarchaeota were the main carbon-fixing bacteria group. As for the nitrogen cycle, nitrogen fixation and dissimilatory nitrate reduction were dominant in water, while nitrification and denitrification were dominant in soil. Proteobacteria, Nitrospirae, Verrucomicrobia, Actinobacteria, Thaumarchaeota and Euryarchaeota contributed to the nitrogen cycle. The study on microbial diversity of Napahai plateau wetlands provides new knowledge for the comprehensive management and protection of wetland environment in China..