摘要

      虽然农业土壤和产品中抗生素抗性基因 (ARG) 的存在已经得到证实，但它们在不同植物部位的分布以及农业实践的贡献，包括再生水灌溉，尚未得到充分解决。为此，我们分析了土壤、根、叶和果实中 7 个 ARG（sul1、blaTEM、blaCTX-M-32、mecA、qnrS1、tetM、blaOXA-58）以及整合酶基因 intl1 的水平。使用与培养无关的定量实时 PCR 方法，使用未受污染的地下水或受处理废水影响的渠道灌溉的商业番茄田。在叶子和果实中发现了 ARG 和 intl1 序列，其水平代表根或土壤中发现的水平的 1% 到 10%。 intl1 序列的相对丰度与 tetM、blaTEM 和 sul1 水平相关，表明这些 ARG 具有高水平迁移潜力。高通量 16S rDNA 测序揭示了样本类型（土壤加根与叶加果实）和采样区之间的微生物组差异，以及假单胞菌科的流行与不同 ARG 水平之间的相关性，尤其是在果实和叶子中。我们得出结论，植物部分（包括水果）中的微生物组组成和 ARGs 水平可能受到农业实践的影响。

      While the presence of antibiotic resistance genes (ARGs) in agricultural soils and products has been firmly established, their distribution among the different plant parts and the contribution of agricultural practices, including irrigation with reclaimed water, have not been adequately addressed yet. To this end, we analyzed the levels of seven ARGs (sul1, blaTEM, blaCTX-M-32, mecA, qnrS1, tetM, blaOXA-58), plus the integrase gene intl1, in soils, roots, leaves, and fruits from two commercial tomato fields irrigated with either unpolluted groundwater or from a channel impacted by treated wastewater, using culture-independent, quantitative real-time PCR methods. ARGs and intl1 sequences were found in leaves and fruits at levels representing from 1 to 10% of those found in roots or soil. The relative abundance of intl1 sequences correlated with tetM, blaTEM, and sul1 levels, suggesting a high horizontal mobility potential for these ARGs. High-throughput 16S rDNA sequencing revealed microbiome differences both between sample types (soil plus roots versus leaves plus fruits) and sampling zones, and a correlation between the prevalence of Pseudomonadaceae and the levels of different ARGs, particularly in fruits and leaves. We concluded that both microbiome composition and ARGs levels in plants parts, including fruits, were likely influenced by agricultural practices.

https://www.sciencedirect.com/science/article/abs/pii/S0048969718341640