碳酸盐型盐湖碳硫元素循环的微生物驱动机制及适应机制

The soda lakes are characterized by high concentrations of sodium carbonate and other dissolved salts，such as sodium chloride and sodium sulfate, and are widespread in arid and semi-arid areas of the earth (e.g. the Inner Mongolia plateau). Despite the harsh haloalkaline conditions, these lakes are usually inhabited by abundant microbial communities and are often highly productive, with gross primary production rates much higher than the global average for lakes and streams, thus the microbiota in the soda lakes would have played an important role in biogeochemical cycling of elements in such extreme aquatic environments. This project will focus on the carbonate-sulfate containing soda lakes, and concentrate on the microbe-driven carbon and sulfur cycling, as well as their environmental adaptation mechanisms in this unique saline system. By means of innovative culture methods, high-throughput culture-independent approaches and molecular biology techniques, we will reveal the mechanisms of the microbe-driven element cycling at levels of microbial community, functional strains, interaction networks, specific metabolic pathways and the related adaptation mechanisms. This project will systematically answer the scientific questions on microbial ecophysiological metabolism related to carbon and sulfur cycling, and provide novel insights into the microbial diversity in the soda lakes and its role in biogeochemistry and biomineralization. The achievements from this project will not only help to understand the microbial geochemical cycling of carbon and sulfur, but may also provide microbial resources and biotechnological potentials for supporting the national ecological health and environmental safety.

碳酸盐型盐湖含有高浓度碳酸钠和其它一些可溶性盐类（如硫酸钠等），在全球干旱和半旱地区（如我国内蒙古高原）广泛分布。该类高盐高pH盐湖尽管环境苛刻，却孕育了丰富的微生物类群，其初级生产力效率甚至可达全球湖泊和流域平均水平的十多倍，在含盐含碱水生生境元素循环中发挥了独特的作用。本项目将基于申请人在嗜盐微生物代谢领域的长期积累，进一步聚焦于碳酸盐型盐湖及其功能微生物组，重点开展该特殊水生生境中碳硫元素循环的微生物驱动机制及其适应机制的研究。拟通过创新性培养技术和非培养策略，结合现代分子生物学方法，从微生物群落，关键功能菌株，特殊代谢途径，互作网络到适应机制等多个层次，系统揭示该类盐湖微生物参与碳硫元素循环的生理代谢机制及其分子基础，探讨碳硫元素循环策略对盐湖微生物特殊群落结构形成的贡献和对盐湖演化的可能影响，并为国家生态健康与环境安全（如含盐碱废水/含硫废气治理等）提供新的微生物资源与技术策略。

碳酸盐型盐湖具有高浓度碳酸盐和其它可溶性盐类。尽管其pH值和盐含量都很高，但却孕育了丰富的微生物类群。本项目聚焦内蒙古地区碳酸盐型盐湖及其功能微生物组，通过培养组技术和非培养策略，结合现代分子生物学方法，从碳酸盐型盐湖微生物群落结构、重要代表类群、关键代谢途径和微生物互作等多个层次，系统开展了盐湖微生物参与碳硫元素循环的生理代谢机制及环境适应机制的研究。重点解析了重要高丰度类群如嗜盐碱螺形杆菌、盐单胞菌、盐原古菌新目、盐纳古菌类群等的系统发生、碳硫代谢潜力及环境适应机制；发现了新型光合固碳嗜盐古菌，阐释了硫氧化细菌及碳贮存嗜盐菌等的碳硫代谢机制和潜在生态效应；揭示了碳酸盐型盐湖病毒组及其基本特征、并首次发现与CRISPR-Cas抗病毒系统偶联的RNA型毒素-抗毒素系统及其护卫CRISPR-Cas的分子机制。并基于碳酸盐型盐湖碳硫代谢机制与适应机制建立了PHA合成、生物脱硫和基因组编辑等相关生物技术。主要研究成果已在Science, Environmental Microbiology等发表学术论文20篇（项目主持人均为通讯作者），申请国家发明专利3项，完成了项目预期目标。本项目取得的研究成果，丰富了碳酸盐型盐湖微生物遗传与代谢多样性，为理解其生理生态功能及适应机制提供了理论依据，也为生物脱硫和生物材料技术创新等提供了资源基础。