Liu Yang, Wen Mengmeng, Hu Rong, Zhao Fazhu, Wang Jun
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi'an, 710127, China; Shaanxi Key Laboratory for Carbon Neutral Technology, Northwest University, Xi'an, 710127, China.
Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity, College of Urban and Environmental Science, Northwest University, Xi'an, 710127, China.
J Environ Manage. 2024 Nov;370:122897. doi: 10.1016/j.jenvman.2024.122897. Epub 2024 Oct 13.
Crop rotation benefits soil fertility and crop yield by providing organic components including cellulose, lignin, chitin, and glucans that are mainly degraded by soil microbial carbohydrate-active enzymes (CAZymes). However, the impacts of crop rotation on soil microbial CAZyme genes are not well understood. Hence, CAZyme genes and families involved in the degradation of differentially originated organic components were investigated using metagenomics among distinct crop rotations. Crop rotation had a more significant effect on soil nitrogen than on carbon fractions with higher content in the complex rotation referring to alfalfa (Medicago sativa L.; 4 year)-potato (Solanum tuberosum L.; 1 year)-winter wheat (3 year; A4PoW3). The composition of soil microbial CAZyme genes related to the degradation of fungi-derived components was more affected by crop rotation compared with the degradation of plant- and bacteria-derived components. The total abundance of CAZyme genes and families was significantly higher in the complex rotation. Notably, CAZyme genes belonging to glycoside hydrolase and glycosyl transferase families had more connections in their network. Moreover, key genes including CE4, GH20, and GH23 assembled toward the middle of the network, and were significantly regulated by dominant soil nitrogen fractions including soil potential nitrogen mineralization and microbial biomass nitrogen. Soil multifunctionality was mostly explained by the composition and total abundance of CAZyme genes, but wheat grain yield was profoundly regulated by fungi-derived components degradation genes under effects of dominant nitrogen fractions. Overall, the findings provide deep insight into the degradation potentials of soil microbial CAZyme genes for developing sustainable crop rotational agroecosystems.
轮作通过提供包括纤维素、木质素、几丁质和葡聚糖在内的有机成分来提高土壤肥力和作物产量，这些有机成分主要由土壤微生物碳水化合物活性酶（CAZymes）降解。然而，轮作对土壤微生物CAZyme基因的影响尚未得到充分了解。因此，利用宏基因组学在不同的轮作方式中研究了参与不同来源有机成分降解的CAZyme基因和家族。与碳组分相比，轮作对土壤氮素的影响更为显著，在涉及苜蓿（紫花苜蓿；4年）-马铃薯（马铃薯；1年）-冬小麦（3年；A4PoW3）的复杂轮作中，土壤氮素含量更高。与植物和细菌来源成分的降解相比，与真菌来源成分降解相关的土壤微生物CAZyme基因组成受轮作的影响更大。复杂轮作中CAZyme基因和家族的总丰度显著更高。值得注意的是，属于糖苷水解酶和糖基转移酶家族的CAZyme基因在其网络中有更多的连接。此外，包括CE4、GH20和GH23在内的关键基因聚集在网络中间，并受到包括土壤潜在氮矿化和微生物生物量氮在内的主要土壤氮组分的显著调控。土壤多功能性主要由CAZyme基因的组成和总丰度来解释，但在主要氮组分的影响下，小麦籽粒产量受到真菌来源成分降解基因的深刻调控。总体而言，这些发现为开发可持续轮作农业生态系统的土壤微生物CAZyme基因降解潜力提供了深入见解。
