摘要
      秸秆还田可以为土壤微生物提供天然的可用碳源，这可能会影响有机污染物的环境行为。在本研究中，构建了一个微观系统来研究稻草还田对磺胺甲恶唑（SMX）和相关抗生素抗性基因（ARGs）命运的影响。结果表明，秸秆还田（土壤干物质的1%）可通过共代谢加速SMX的降解。在稻草处理组中，SMX在前6天内迅速分解为小分子化合物（如（Z）-1-氨基-3-氧代丁-1-烯-1-胺和苯亚磺酸），60天后检测不到SMX；而对于没有稻草的SMX组，在第60天仍然保留了1.3 mg kg−1的SMX。秸秆还田可以提高参与SMX降解的变形杆菌的相对丰度，包括Microvirga和Ramlibacter，它们通过矿化成分和芳香化合物的降解途径共同代谢SMX。此外，秸秆还田显著消除了ARG。60天后，有稻草的处理组的int1和sul1丰度低于没有稻草的SMX组的十分之一。细菌群落和环境因素的冗余度和网络分析表明，溶解有机碳和属于变形菌门的细菌和放线菌门可能在消除ARGs方面发挥积极作用。我们的研究结果表明，秸秆还田可以促进SMX和相应ARGs的同时消除，这为有效治疗农田中的抗生素和ARGs提供了一种很有前途的方法。
Abstract
Straw return could provide a natural available carbon source for the soil microorganisms, which might affect the environmental behaviours of organic pollutants. In this study, microcosm system was constructed to investigate the effect of rice straw return on the fate of sulfamethoxazole (SMX) and related antibiotic resistance genes (ARGs). The results showed that straw return (1% of soil dry mass) could accelerate the degradation of SMX via co-metabolism. In the treatment group with rice straw, SMX was rapidly decomposed into small molecular compounds (e.g., (Z)-1-amino-3-oxobut-1-en-1-aminium and benzenesulfinic acid) within the first six days, and SMX was undetectable after 60 days; while for the SMX group without rice straw, 1.3 mg kg−1 of SMX still remained at the 60th day. Straw return could enhance the relative abundances of Proteobacteria involved in SMX degradation, including Microvirga and Ramlibacter, which co-metabolized SMX via the degradation pathways of mineralizable components and aromatic compound. Furthermore, straw return significantly eliminated the ARGs. After 60 days, the int1 and sul1 abundances of the treatment group with rice straw were less than one-tenth of the SMX group without rice straw. The redundancy and network analysis of bacterial community and environmental factors showed that dissolved organic carbon and bacteria belonged to Proteobacteria and Actinobacteria might play positive roles in eliminating ARGs. Our results demonstrate that straw return could promote the simultaneous elimination of SMX and corresponding ARGs, which provides a promising approach to effectively treat antibiotics and ARGs in the farmland.

https://www.sciencedirect.com/science/article/abs/pii/S0048969721056023