摘要

    就未来几十年的全球发展而言，抗生素抗性和二氧化碳含量的上升被认为是我们将面临的最重大挑战。然而，很少研究CO 2升高对土壤抗生素抗性的影响。我们使用了自由空气CO2富集系统，研究了在目前的CO2浓度（370 ppm）和将来的CO2浓度升高（eCO2，2100年预计为570 ppm）下向土壤中施用矿物和有机肥料带来的潜在风险。单独使用有机肥料替代（用50％N代替矿物肥料）可增加植物吸收和磺胺二甲嘧啶的土壤残留量，并丰富了磺酰胺抗性基因（sul1，sul2），四环素抗性基因（tetG，tetM）和1类整倍体（intl1） 。但是它降低了稻米的产量（降低了7.6％）。相比之下，eCO2通过有机肥替代降低了sul2，tetG和intl1基因丰度，同时增加了谷物产量（增加了8.4％）。变形杆菌和硝化螺旋菌是抗生素抗性基因（ARG）的潜在宿主。通过intl1的水平基因转移可能在eCO2下传播的ARGs中起重要作用。结果表明，未来升高的CO2浓度可能会改变有机肥替代对水稻产量和土壤ARGs的影响，对未来医学和人类健康的影响未知。

    Antibiotic resistance and rising CO2 levels are considered among the most significant challenges we will face in terms of global development over the following decades. However, the impact of elevated CO2 on soil antibiotic resistance has rarely been investigated. We used a free-air CO2 enrichment system to investigate the potential risks posed by applying mineral and organic fertilizers to paddy soil at current CO2 concentration (370 ppm) and future elevated CO2 (eCO2, 570 ppm predicted for 2100). Organic fertilizer substitution (substituting the mineral fertilizer by 50% N) alone increased the plant uptake and soil residue of sulfamethazine, and enriched sulfonamide resistance genes (sul1, sul2), tetracycline resistance genes (tetG, tetM) and class 1 integron (intl1). But it decreased the rice grain yield (by 7.6%). Comparatively, eCO2 decreased the sul2, tetG and intl1 gene abundances by organic fertilizer substitution, and meanwhile increased grain yield (by 8.4%). Proteobacteria and Nitrospirae were potential hosts of antibiotic resistance genes (ARGs). Horizontal gene transfer via intl1 may play an important role in ARGs spread under eCO2. Results indicated that future elevated CO2 concentration could modify the effects of organic fertilizer substitution on rice yield and soil ARGs, with unknown implications for future medicine and human health.

    https://www.sciencedirect.com/science/article/abs/pii/S0048969720354279