Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China.
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China.
Sci Total Environ. 2020 Nov 1;741:140457. doi: 10.1016/j.scitotenv.2020.140457. Epub 2020 Jun 23.
Rhizosphere is a crucial site for the proliferation of antibiotic resistance genes (ARGs) in agricultural soil. Pesticide contamination is ubiquitous in soil, such as chlorpyrifos as one of the most commonly used pesticides. However, limited knowledge is reported about ARGs profiles changes and the driving mechanism of ARGs prevalence in rhizosphere soil after adding pesticide. In this study, irrespective of chlorpyrifos presence, the abundances of ARGs (tetM, tetO, tetQ, tetW, tetX, sul1 and sul2) and intI1 in rhizosphere soil of wheat were obviously higher than those in bulk soil. 20.0 mg·kg chlorpyrifos significantly increased the abundance of total ARGs and intI1 in bulk soil, respectively, at day 50 and 100, but not in rhizosphere soil. Rhizosphere influence on ARGs was far greater than chlorpyrifos. ARGs and intI1 abundances were higher at day 50 than ones at day 100. C/N ratio and NO-N content, which were affected by rhizosphere and cultivation time, significantly explained the increased ARGs. Compared to bulk soil, rhizosphere shifted host bacteria of tetracycline resistance genes (TRGs), intI1 at genus level, and host bacteria of sul1, sul2 at phylum level. Rhizosphere simplified the linkage of ARGs, host bacteria and metabolites. Bacterial communities played important roles in the variation of ARGs and intI1, and the difference in the distribution of potential hosts between bulk and rhizosphere soil was related to metabolites abundance and composition. These results provide valuable information for understanding the linkage of ARGs, associated bacteria communities and metabolites in the wheat rhizosphere soil.
根际是农业土壤中抗生素抗性基因（ARGs）增殖的关键场所。农药污染在土壤中普遍存在，例如毒死蜱是最常用的农药之一。然而，关于添加农药后根际土壤中 ARGs 谱变化及其流行的驱动机制的知识有限。在这项研究中，无论是否存在毒死蜱，小麦根际土壤中 ARGs（tetM、tetO、tetQ、tetW、tetX、sul1 和 sul2）和 intI1 的丰度明显高于非根际土壤。20.0 mg·kg 的毒死蜱在第 50 和 100 天分别显著增加了非根际土壤中总 ARGs 和 intI1 的丰度，但在根际土壤中没有增加。根际对 ARGs 的影响远远大于毒死蜱。第 50 天的 ARGs 和 intI1 丰度高于第 100 天。受根际和种植时间影响的 C/N 比和 NO-N 含量显著解释了 ARGs 的增加。与非根际土壤相比，根际改变了四环素抗性基因（TRGs）、属水平的 intI1 以及 sul1、sul2 门水平的宿主细菌。根际简化了 ARGs、宿主细菌和代谢物的联系。细菌群落在 ARGs 和 intI1 的变化中发挥着重要作用，非根际和根际土壤中潜在宿主的分布差异与代谢物丰度和组成有关。这些结果为了解小麦根际土壤中 ARGs、相关细菌群落和代谢物的联系提供了有价值的信息。
