摘要
      日益增长的“一个健康”概念要求更深入地了解抗生素耐药性在植物微生物群中的传播。尽管有大量已发表的证据表明，微塑料可以促进抗生素抗性基因（ARGs）在环境中的传播，但微塑料是否以及如何影响植物内生抗性在很大程度上是未知的。在这里，我们检测了微塑料压力下玉米和小麦土壤根连续体上的ARGs。还包括对重金属的修正，因为它们也可以对ARG扩散施加选择性压力。作物种类和基因型对根系内生ARG的丰度和多样性有显著影响。在玉米ZD958内生菌中观察到最大的ARG丰度（每16S rRNA基因0.215个拷贝），其次是玉米XY335（每16S rRNA基因0.092个拷贝）。对于每种作物基因型，用微塑料和重金属改良显著增加了ARG的丰度，并改变了其在根内生菌中的分布。内生ARG变异与内生微生物组、根际细菌群落和抗性组密切相关。此外，内生ARGs的水平与可移动遗传元件（MGE）的丰度呈正相关。这些发现表明，根内生抗性主要受作物物种的影响，微塑料可能通过改变根相关微生物组和促进MGE介导对内生抗性表现出增强作用。总的来说，这项研究首次强调了微塑料诱导的根内生ARG的出现和传播。
Abstract
The increasing One-Health concept calls for a more in-depth understanding of the dissemination of antibiotic resistance in plant microbiomes. While there is considerable published evidence that microplastics can promote the spread of antibiotic resistance genes (ARGs) in the environment, whether and how microplastics impact the plant endophytic resistome are largely unknown. Here we examined the ARGs along the soil-root continuum of maize and wheat under the pressure of microplastics. Amendment with heavy metals was also included as they can apply the selective pressure for ARG spread as well. The crop species and genotypes had significant effects on the root endophytic ARG abundance and diversity. The greatest ARG abundance was observed in the maize ZD958 endophytes (0.215 copies per 16S rRNA gene), followed by the maize XY335 (0.092 copies per 16S rRNA gene). For each crop genotype, amendment with microplastics and heavy metals significantly increased the ARG abundances and changed their profiles in root endophytes. The endophytic ARG variances were closely associated with the endophytic microbiome, the rhizosphere bacterial communities and resistome. Additionally, the level of endophytic ARGs was positively relevant to the abundance of mobile genetic elements (MGEs). These findings suggested that the root endophytic resistome was primarily affected by the crop species, and microplastics might show enhancement effects on the endophytic resistome via changing the root-associated microbiome and facilitating the MGE mediation. Overall, this study, for the first time, highlights the root endophytic ARG emergence and dissemination induced by microplastics.

https://www.sciencedirect.com/science/article/abs/pii/S0304389422018854