Cong Mengfei, Zhang Zhihao, Tariq Akash, Sardans Jordi, Wang Weiqi, Gao Yanju, Dong Xinping, Zhao Guangxing, Peñuelas Josep, Zeng Fanjiang
Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; College of Ecology and Environment, Xinjiang University, Urumqi, 830046, China; Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China.
Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China.
J Environ Manage. 2025 Aug;390:126417. doi: 10.1016/j.jenvman.2025.126417. Epub 2025 Jul 1.
Microorganisms decompose plant residue in soil and incorporate it to their biomass, thereby promoting soil carbon (C) accumulation. However, the mechanisms underlying microbial-mediated plant- and microbial-derived C degradation and their response to afforestation remain unclear. Here, soil organic C (SOC), carbohydrate-activated enzymes (CAZymes), and C acquiring enzyme were utilized to investigate microbial-mediated SOC formation after afforestation (3, 7, and 10 years) in an arid region, with uncultivated wasteland serving as the control (0 years). Results showed that the relative abundance of microbial CAZymes degrading plant-derived C (cellulose, hemicellulose, lignin, 90.87-91.72 %) exceeded that degrading microbial-derived C (8.28-8.13 %). Additionally, CAZymes degrading bacterial-derived C (peptidoglycan, 6.60-7.46 %) was higher than that degrading fungal-derived C (chitin and glucans, 1.37-2.20 %). Intriguingly, temporal dynamics revealed non-linear dynamics-SOC content, enzyme activities, and plant-/microbial-derived C peaked at 7-year of afforestation before declining in 10-year of afforestation. Afforestation reduced the abundance of genes degrading plant-derived C, including cellulose- and hemicellulose-specific gene families. In contrast, the abundance of genes degrading bacterial-derived C showed a decreasing and then increasing trend as afforestation, while genes degrading fungal-derived C showed the opposite trend. In summary, afforestation-induced changes in soil nutrients alter the abundance of microbial functional genes degrading bacterial-, fungal-, and plant-derived C, thereby influences SOC dynamics through these C components. These findings underscore the significance of the relationship between functional genes and microbial metabolism in SOC accumulation.
微生物分解土壤中的植物残体并将其纳入自身生物量，从而促进土壤碳（C）积累。然而，微生物介导的植物和微生物源碳降解的潜在机制及其对造林的响应仍不清楚。在此，利用土壤有机碳（SOC）、碳水化合物活性酶（CAZymes）和碳获取酶，研究了干旱地区造林（3年、7年和10年）后微生物介导的SOC形成情况，以未开垦的荒地作为对照（0年）。结果表明，降解植物源碳（纤维素、半纤维素、木质素，90.87 - 91.72%）的微生物CAZymes相对丰度超过了降解微生物源碳（8.28 - 8.13%）的相对丰度。此外，降解细菌源碳（肽聚糖，6.60 - 7.46%）的CAZymes高于降解真菌源碳（几丁质和葡聚糖，1.37 - 2.20%）的CAZymes。有趣的是，时间动态揭示了非线性动态——SOC含量、酶活性以及植物/微生物源碳在造林7年时达到峰值，随后在造林10年时下降。造林降低了降解植物源碳的基因丰度，包括纤维素和半纤维素特异性基因家族。相反，降解细菌源碳的基因丰度随着造林呈现先降低后增加的趋势，而降解真菌源碳的基因则呈现相反趋势。总之，造林引起的土壤养分变化改变了降解细菌、真菌和植物源碳的微生物功能基因丰度，从而通过这些碳组分影响SOC动态。这些发现强调了功能基因与微生物代谢在SOC积累中的关系的重要性。
