土壤次生代谢产物: 连接微生物残体与土壤有机碳库的生态纽带
Soil secondary metabolites: An ecological link bridging microbial residues and soil organic carbon pools
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摘要: 土壤有机质是由来自植物和微生物细胞裂解和代谢产生的小分子物质组成的复杂连续体。微生物残体是土壤有机碳的重要来源, 在调控土壤有机碳库的结构和稳定性方面发挥着重要作用。微生物残体和土壤有机碳库在微生物代谢水平存在密切的生态关联, 但是对于微生物代谢如何调控微生物残体对土壤有机碳库的贡献, 尚缺乏直接的试验证据和深入的机理性认识。本文从微生物残体对土壤有机碳库的贡献、次生代谢产物对土壤碳周转的调控作用、微生物残体与土壤有机碳库的生态关联等3个方面阐述了从微生物代谢水平探究微生物残体贡献土壤有机碳库的理论基础。作者提出未来应该基于野外控制实验平台, 综合运用非靶向胞外代谢组学、宏基因组学、生物标记物等技术, 探究土壤次生代谢产物的分子组成与可获得性对养分输入改变的响应规律, 解析其在介导微生物残体贡献土壤有机碳库的调控效应及其背景依赖性, 进而从微生物代谢的角度揭示微生物残体贡献土壤有机碳库的生态学机制。相关研究的开展不仅有助于从微生物代谢角度丰富土壤有机质形成与稳定的生态学理论, 也可为应对未来气候变化和适应性管理提供科技支撑。Abstract: Soil organic matter is a complex continuum composed of small molecules from cell lysis and metabolism of plant and microbe. Microbial residues are an important source of soil organic carbon (SOC) and play a vital role in regulating the structure and stability of the SOC pool. Microbial residues and the SOC pool are closely associated with soil microbial activity and are closely linked at the metabolic level. However, direct empirical evidence and in-depth mechanism understanding of how microbial metabolism regulates the contribution of microbial residues to the SOC pool remain scarce. In this paper, we discuss the theoretical basis of the microbial residue contribution to SOC pool from the perspectives of the contribution of microbial residues to SOC pool, the regulation of secondary metabolites on soil carbon turnover and the ecological linkages between microbialresidues and SOC pool. We emphasize that future researches should focus on three areas: 1) investigating the response of the molecular composition and bioavailability of soil secondary metabolites to variations in nutrient input by employing non-targeted exometabolomics, metagenomics, and biomarkers technologies; 2) Elucidating the regulatory effects of soil secondary metabolites on mediating microbial residue contributions to the SOC pool and their context-dependence characteristics; 3) Unraveling the ecological mechanisms by which microbial residues contributing to the SOC pool from the perspective of microbial metabolism. The implementation of the relevant research will no only enrich the ecological theory of soil organic matter formation and stability from a microbial metabolism perspective, but also provide scientific and technological support for climate change mitigation and adaptive strategies in the future.
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