土壤主要还原转化过程中微生物功能基因多样性研究进展

Key microbial functional genes and their diversity involved in soil typical reduction processes: A review

土壤是一个复杂的氧化还原体系,存在大量活跃的生源要素和污染物的生物地球化学循环过程,氮还原、铁还原、硫酸盐还原、产甲烷和还原脱卤等反应过程伴随着频繁而密切的交互作用,对自然生态系统中的物质代谢和能量流动具有决定性的影响。近年来,随着分子生物学技术的发展,以功能基因为生物标志物,对土壤环境中不同还原条件下相关功能微生物的群落结构、分布特性和丰度变化等的表征及其对土壤中还原过程的介导机制研究是国际社会关注的热点。本文综述了土壤中几种重要还原转化过程中的关键功能基因,旨在进一步揭示自然淹水土壤中参与介导氮还原、硫酸盐还原、铁还原、产甲烷以及还原脱卤等过程的重要微生物的群落结构和功能,最终为阐明生源要素还原转化耦合污染物降解过程中的微生物学介导机制提供参考依据。

Soil is a complex redox system where many active biogeochemical processes co-occurred, such as denitrification, iron/sulfate reduction, methanogenesis and reductive dehalogenation, etc. Due to their frequent and close interaction, these typical redox processes make a great contribution in regulating the transformation/transportation of elements and pollutants in a natural soil ecosystem. Recently, with the development of molecular biology technology,studies regarding the microbial community structure, distribution characteristics and relative abundance in soil environment, based on functional gene biomarkers, become a hot topic around the world. The key genes encoding for specific functional enzymes in typical redox processes have been continually improved. This greatly advanced our understanding with respect to the specific metabolic pathway of elements and pollutants in soils, and promoted the in-depth development in studies on environmental microbial ecology. However, due to the diversity of microorganisms and functional genes, the influence of different environmental factors, and their extensive interactions in the natural soil environment, our knowledge currently available for demonstrating the complicated metabolic pathways and the coupling mechanism among different elements and pollutants are still finite. Therefore, the key functional genes and their diversity involved in several major reduction processes in soils were reviewed in this paper. Through comprehensive analysis of the microbial community structure and functional properties during the reduction processes of NO_3^-, Fe（Ⅲ） and SO_4^（2-）, the process of methanogenesis, and the reductive dehalogenation of halogenated organic pollutants, we aim to explore the coupling mechanism between typical soil redox processes and the reductive removal of halogenated organic pollutants,thereby developing an improved strategy for pollution remediation.