摘要
      农业土壤是抗生素抗性基因（ARGs）的重要库，ARGs与土壤微生物密切相关。环境因素和共存污染物可能作为ARG增殖的促进剂或抑制剂，影响农业绿色发展。然而，在农业土壤中，仍然缺乏关注潜在环境驱动因素和ARGs相互作用的研究。在这里，我们探索了长江三角洲241个土壤样本的微生物特征，并分析了微生物结构、ARGs和典型的位点特异性因素之间的关系。我们发现，大多数ARGs的丰度与真菌和细菌的比例（F/B）呈负相关，而与革兰氏阳性和革兰氏阴性微生物的比例（G+/G−）呈正相关。共现网络揭示了18个特定地点因子之间的显著关联，包括6个气象因子、5个土壤理化性质、5个共存有机污染物和2个共存重金属。随机森林分析表明，F/B主要受土壤有机质和共存多氯联苯的影响，而G+/G−主要受土壤总磷和水分含量的调节，这可能导致它们与ARG丰度的差异关系。此外，气象因素（>30%）在解释F/B和G+/G−结构中的贡献在所有特定地点因素中最高。通过通径分析表明，气象因素可能通过物理化学性质、微生物结构和共存有机污染物的直接正向或间接途径影响ARG丰度，我们认为气象因素是ARG增殖的潜在促进剂。总之，这些结果增加了我们对农业土壤作为ARGs热点的理解，并突出了气象因素作为土壤ARGs潜在推动者的作用，为我们科学调控ARGs污染，促进绿色农业发展提供了参考。
Abstract
Agricultural soils are important reservoirs for antibiotic resistance genes (ARGs), which is closely linked to soil microorganisms. Environmental factors and co-existed pollutants may function as promoters or inhibitors for ARG proliferation to influence the agriculture green development. However, research focusing on the interaction of potential environmental drivers and ARGs is still lacking in agricultural soils. Here, we explored the microbial profile in 241 soil samples in Yangtze River Delta, and analyzed the relationship of microbial structures, ARGs, and typical site-specific factors. We found that the abundance of most ARGs was negatively correlated with the ratio of fungi and bacteria (F/B), whereas positively correlated with the ratio of gram-positive and gram-negative microbes (G+/G−). The co-occurrence network revealed significant associations among 18 site-specific factors, including 6 meteorological factors, 5 soil physicochemical properties, 5 co-existed organic pollutants, and 2 co-existed heavy metals. Random forest analysis demonstrated that F/B was mainly influenced by soil organic matters and co-existed polychlorinated biphenyls, while G+/G− was predominately regulated by soil total phosphorus and moisture content, which possibly resulting in their difference relationship with ARG abundance. Besides, the contribution of meteorological factors (>30%) in the explanation for F/B and G+/G− structures was the highest among all the site-specific factors. Together with path analysis showing meteorological factors probably affecting the ARG abundance through direct positive ways or indirect paths via physicochemical properties, microbial structure, and co-existed organic pollutants, we considered meteorological factors as the potential promoters for ARG proliferation. Collectively, these results increase our understanding of agricultural soils as hotspots of ARGs, and highlight the underappreciated role of meteorological factors as potential promoters for soil ARGs, providing reference for us to regulate ARG pollution scientifically to improve the development of green agriculture.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722035719