摘要

    已有文献证明使用有机肥料可以促进土壤生态系统中抗生素抗性基因（ARG）的传播。但是，很少讨论土壤动物在这一过程中的作用，这妨碍了我们预测ARGs的命运和控制其生长的能力。在这里，我们使用高通量定量聚合酶链反应（HT-qPCR），研究了长期（5年，8年和10年）施肥处理（对照，无机肥料和混合肥料）对土壤肥力的影响。 ARG在土壤，线虫和earth之间的转移。我们在线虫和earth中发现了ARG的独特命运，前者的ARG富集水平高于后者。施肥影响土壤中ARGs的数量和含量，施肥持续时间改变了ARGs的组成。在快速期望最大化微生物源追踪分析的支持下，土壤，线虫和earth肠道中共有的ARGs证明了ARGs在此短土壤食物链中的营养转移潜力。施肥持续时间减少了ARGs的转移，这主要归因于worm肠道菌群中ARGs的减少。这项研究确定了ARGs在土壤线虫-of食物链中的转移是在土壤生态系统中更广泛地传播ARGs的潜在机制。

    Applying organic fertilizers has been well documented to facilitate the dissemination of antibiotic resistance genes (ARGs) in soil ecosystems. However, the role of soil fauna in this process has been seldom addressed, which hampers our ability to predict the fate of and to manage the spread of ARGs. Here, using high-throughput quantitative polymerase chain reaction (HT-qPCR), we examined the effect of long-term (5-, 8-, and 10-year) fertilization treatments (control, inorganic fertilizers, and mixed fertilizers) on the transfer of ARGs between soil, nematodes, and earthworms. We found distinct fates for ARGs in the nematodes and earthworms, with the former having higher enriched levels of ARGs than the latter. Fertilization impacted the number and abundance of ARGs in soil, and fertilization duration altered the composition of ARGs. Shared ARGs among soil, nematodes, and earthworm guts supported by a fast expectation-maximization microbial source tracking analysis demonstrated the trophic transfer potential of ARGs through this short soil food chain. The transfer of ARGs was reduced by fertilization duration, which was mainly ascribed to the reduction of ARGs in the earthworm gut microbiota. This study identified the transfer of ARGs in the soil-nematode-earthworm food chain as a potential mechanism for a wider dissemination of ARGs in the soil ecosystem.

    https://pubs.acs.org/doi/abs/10.1021/acs.est.0c03893