摘要

       抗生素耐药性的日益流行是对公共健康的全球威胁。土壤中的抗生素抗性基因（ARGs）已被证明能够进入食物链。减缓抗生素耐药性从土壤向作物传播的策略对于食品安全和人类健康非常重要。生物炭土壤改良剂是一种广泛使用的提高土壤肥力的方法。然而，生物炭对减轻土壤和有机生产的生食蔬菜的抗生素耐药性的影响在很大程度上是未知的。为了深入了解这种影响，进行了在用生物炭改良的土壤中种植芸苔的盆栽实验，并通过 HT-qPCR 对抗生素抗性基因 (ARG) 进行了表征，针对几乎所有主要类别的 ARG 和 10 个移动遗传元件 (MGE)基因。在土壤和叶际样品中共鉴定出 131 个 ARG 和 9 个 MGE。生物炭添加后，非种植土壤中ARGs的丰度显着降低。相比之下，根际和叶际的 ARGs 没有显着减少，表明蔬菜种植影响了生物炭改良土壤中的抗生素抗性。为了理解这种影响，对土壤和叶际内的细菌系统发育结构进行了分析，发现它们与其各自的抗性组相关，表明种植可以通过改变微生物群落组成来影响生物炭对土壤抗生素抗性组的影响。结构方程模型进一步表明，较高的细菌多样性对应于较低的 ARGs 含量。这些结果表明，仅生物炭改良剂不足以减轻种植土壤和作物中的 ARGs 水平，相反，维持或增加土壤微生物多样性可能更有助于减轻 ARG 的传播和积累。

       The increasing prevalence of antibiotic resistance is a global threat to public health. Antibiotic resistance genes (ARGs) in soil have been demonstrated to be able to enter food chain. Strategies to mitigate the spread of antibiotic resistance from soil to crops are of great importance for food safety and human health. Soil amendment with biochar is a widely used approach to improve soil fertility. However, the impact of biochar on mitigating antibiotic resistance of soil and organically produced vegetables that are eaten raw is largely unknown. To gain insights into this impact, pot experiments planting Brassica chinensis L. in soil amended with biochar were conducted and antibiotic resistance genes (ARGs) were characterized by HT-qPCR targeting almost all major classes of ARGs and 10 mobile genetic elements (MGEs) marker genes. A total of 131 ARGs and 9 MGEs in soil and phyllosphere samples were identified. After biochar amendment, the abundance of ARGs was significantly decreased in non-planted soil. By comparison, no significant decrease of ARGs was found in rhizosphere and phyllosphere, indicating that vegetable planting affected antibiotic resistome in biochar-amended soil. To understand this effect, bacterial phylogeny structures within soil and phyllosphere were analyzed and found to correlate with their respective resistome, indicating that planting can influence the effect of biochar on soil antibiotic resistome by altering microbial community compositions. Structure equation models further revealed that a higher bacterial diversity corresponded to a decreased ARGs content. These results suggested that biochar amendment alone was not sufficient enough to alleviate ARGs level in planted soil and crops, instead, maintaining or increasing soil microbial diversity is potentially more useful in mitigating ARG spread and accumulation.

https://www.sciencedirect.com/science/article/abs/pii/S0038071718300154