摘要

       除草剂是农业中使用最广泛的化学品之一。虽然已知它们对非目标生物有害，但除草剂对土壤微生物群落的组成和功能的影响仍不清楚。在这里，我们展示了三种广泛使用的除草剂——草甘膦、草铵膦和麦草畏——的应用增加了土壤微生物组中抗生素抗性基因 (ARG) 和移动遗传元件 (MGE) 的流行，而细菌的丰度、多样性和组成没有明显变化。社区。从机制上讲，这些结果可以通过对更耐受的基因型的阳性选择来解释，这些基因型在以前充分表征的除草剂和 ARG 中获得了几个突变。此外，除草剂暴露增加了细胞膜通透性和多药耐药质粒的结合频率，促进了细菌之间的 ARG 运动。在中国 11 个省的农业土壤中发现了类似的模式，其中除草剂的施用以及土壤中草甘膦残留的水平与相对于无除草剂对照点的 ARG 和 MGE 丰度增加有关。总之，我们的结果表明，除草剂的应用可以通过改变土壤微生物组的遗传组成来丰富 ARGs 和 MGEs，这可能会导致农业环境中的全球抗菌素耐药性问题。

       Herbicides are one of the most widely used chemicals in agriculture. While they are known to be harmful to nontarget organisms, the effects of herbicides on the composition and functioning of soil microbial communities remain unclear. Here we show that application of three widely used herbicides—glyphosate, glufosinate, and dicamba—increase the prevalence of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in soil microbiomes without clear changes in the abundance, diversity and composition of bacterial communities. Mechanistically, these results could be explained by a positive selection for more tolerant genotypes that acquired several mutations in previously well-characterized herbicide and ARGs. Moreover, herbicide exposure increased cell membrane permeability and conjugation frequency of multidrug resistance plasmids, promoting ARG movement between bacteria. A similar pattern was found in agricultural soils across 11 provinces in China, where herbicide application, and the levels of glyphosate residues in soils, were associated with increased ARG and MGE abundances relative to herbicide-free control sites. Together, our results show that herbicide application can enrich ARGs and MGEs by changing the genetic composition of soil microbiomes, potentially contributing to the global antimicrobial resistance problem in agricultural environments.

https://academic.oup.com/mbe/article/38/6/2337/6133234?login=true