摘要 

    含有大量抗生素和抗生素抗性基因（ARG）的肥料被广泛用于农业土壤中，并可能导致ARGs在土壤环境中的进化和扩散。在本研究中，在华北平原（NCP）上取样了15年获得肥料或化肥的土壤，华北平原是中国集约化农业的主要地区之一。高通量定量PCR和测序技术用于评估长期施用肥料或化肥对ARG和微生物群落分布的影响。从所有土壤样品中共成功扩增出114个独特的ARG。施用粪肥显着增加了ARG的相对丰度和可检测数量，最多达0.23个拷贝/ 16S rRNA基因和81个独特的ARG。肥料施肥的土壤中ARGs的增加主要是由于肥料增加了本地土壤ARGs的含量。相反，化肥仅适度影响ARGs的多样性，对总ARGs的相对丰度没有显着影响。此外，粪肥的施用增加了与大多数类型的ARGs显着正相关的可移动遗传元件（MGEs）的丰度，表明通过MGEs进行水平基因转移可能在ARGs的传播中起重要作用。此外，肥料和化肥的施用显着影响了微生物群落结构，变异分区分析表明，微生物群落的变化是塑造抗生素抗药性的主要驱动力。两者合计，我们的结果提供深入了解肥料和化学施肥对集约型农业生态系统中ARG传播的长期影响。

    Manure, which contains large amounts of antibiotics and antibiotic resistance genes (ARGs), is widely used in agricultural soils and may lead to the evolution and dispersal of ARGs in the soil environment. In the present study, soils that received manure or chemical fertilizers for 15 years were sampled on the North China Plain (NCP), which is one of the primary areas of intensive agriculture in China. High-throughput quantitative PCR and sequencing technologies were employed to assess the effects of long-term manure or chemical fertilizer application on the distribution of ARGs and microbial communities. A total of 114 unique ARGs were successfully amplified from all soil samples. Manure application markedly increased the relative abundance and detectable numbers of ARGs, with up to 0.23 copies/16S rRNA gene and 81 unique ARGs. The increased abundance of ARGs in manure-fertilized soil was mainly due to the manure increasing the abundance of indigenous soil ARGs. In contrast, chemical fertilizers only moderately affected the diversity of ARGs and had no significant effect on the relative abundance of the total ARGs. In addition, manure application increased the abundance of mobile genetic elements (MGEs), which were significantly and positively correlated with most types of ARGs, indicating that horizontal gene transfer via MGEs may play an important role in the spread of ARGs. Furthermore, the application of manure and chemical fertilizers significantly affected microbial community structure, and variation partitioning analysis showed that microbial community shifts represented the major driver shaping the antibiotic resistome. Taken together, our results provide insight into the long-term effects of manure and chemical fertilization on the dissemination of ARGs in intensive agricultural ecosystems.

   https://www.frontiersin.org/articles/10.3389/fmicb.2020.00062/full