摘要
      农业土壤和微塑料（MP）是抗生素抗性基因（ARGs）的热点。塑料覆盖物是农业土壤中MPs最重要的来源。长期覆盖MP暴露土壤中的ARGs、可移动遗传元素（MGE）及其宿主特征尚不清楚。在本研究中，利用宏基因组学研究了ARGs和MGEs在中国八个地膜使用历史悠久的省份的分布模式。共鉴定出204种ARGs亚型和数千种MGE（14个整合子、28个插入子和2993个质粒）。在MP胶片污染的地点也发现了类似的ARGs多样性。高丰度的ARGs类型更为集中，多药耐药基因是占优势的ARGs。来自塑料薄膜使用历史较长地区（如新疆省）的土壤中ARGs和MGEs的丰度较高。ARG和MGE的分布呈现出模块化的网络分布模式。共有27种ARG亚型和29种MGE表现出共现网络关系。发现了10多种常见的ARGs和MGE宿主，如假单胞菌，其丰度在包括新疆在内的三个省份最高。这项研究可能有助于阐明长期MP残留对ARGs在土壤中发生和传播的影响机制。
Abstract
Agricultural soils and microplastics (MPs) are hotspots for antibiotic resistance genes (ARGs). Plastic mulch is the most important source of MPs in agricultural soil. ARGs, mobile genetic elements (MGEs), and their host profiles in long-term mulch MP-exposed soils remain unclear. In the present study, metagenomics was used to investigate the distribution patterns of ARGs and MGEs in eight Chinese provinces with a long history of plastic mulch use. A total of 204 subtypes of ARGs and thousands of MGEs (14 integrons, 28 insertions, and 2993 plasmids) were identified. A similar diversity of ARGs was found among MPs film-contaminated sites. The types of ARGs with a high abundance were more concentrated, and multidrug resistance genes were the dominant ARGs. Soils from regions with a longer history of plastic film use (such as Xinjiang province) had a higher abundance of ARGs and MGEs. The distribution of ARGs and MGEs exhibited a modular network distribution pattern. A total of 27 ARG subtypes and 29 MGEs showed co-occurrence network relationships. More than 10 common hosts of ARGs and MGEs, such as Pseudomonas, were found, and their abundances were highest in three provinces, including Xinjiang. This study may help elucidate the impact mechanism of long-term MP residues on the occurrence and spread of ARGs in soil.

https://www.sciencedirect.com/science/article/abs/pii/S0045653522037286