摘要
      河流在不同环境分区之间接收和运输抗性物质方面发挥着重要作用。然而，人们对水和沉积物之间的抗性和移动性的差异及其潜在机制仍知之甚少。本研究以中亚干旱地区的重要水源伊犁河为研究对象。基于宏基因组装盒和组装基因组（MAG）分析，研究了水和沉积物中抗性体、移动性体及其宿主的综合图谱。沉积物中抗性体和迁移体的相对丰度分别为28.0–67.8×/Gb和46.5–121.1×/Gb，显著高于水中的抗性体和移动体的相对丰富度（23.1–52.8×/Gb和25.3–67.7×/Gb）。从相对丰度来看，水和沉积物中的ARG主要类型是多药和大环内酯类林可酰胺类链脲菌素（MLS）抗性基因。转座子酶主导了移动体的相对丰度，其次是插入元件和整合酶。在水和沉积物中，抗性组和移动性组的相对丰度之间存在很强的相关性（r>0.6和p<0.01），表明移动性组在伊犁河抗性组的传播中发挥了重要作用。通过MAG分析，多药耐药基因的主要宿主在水中（α-变形菌和γ-变形菌）和沉积物（γ-变形杆菌）中不同。伊犁河水和泥沙之间存在着明显的抗性组和移动性组分。差异抗性组和迁移组的特异性占有分析表明，差异ARGs的发生频率和栖息地选择决定了水和沉积物的抗性。相比之下，栖息地是形成伊犁河流动性的主要驱动因素。
Abstract
Rivers play an important role in receiving and transporting the resistome among different environmental compartments. However, the difference in resistome and mobilome between the water and sediment and their underlying mechanisms were still poorly understood. In this study, the Ili River, an important water source in the arid area of Central Asia, was selected as the studied target. The comprehensive profile of resistome and mobilome and their host in water and sediment were studied based on metagenomic binning and assembled genome (MAG) analysis. The relative abundance of resistome and mobilome in sediment were 28.0 – 67.8 × /Gb and 46.5 – 121.1 × /Gb, respectively, which were significantly higher than those in water (23.1 – 52.8 ×/Gb and 25.3 – 67.7 ×/Gb). Multidrug and macrolides-lincosamides-streptogramin (MLS) resistance genes were the main ARG types in both water and sediment from relative abundance. Transposases dominated the relative abundance of mobilome, followed by insert elements and integrases. Strong correlations were found between the relative abundance of resistome and mobilome (r > 0.6 and p < 0.01) in both water and sediment, indicating the mobilome played an important role in the propagation of resistome in the Ili River. The main hosts for multidrug resistance genes via MAG analysis differed in water (Alphaproteobacteria and Gammaproteobacteria) and sediment (Gammaproteobacteria). Distinct compositions of resistome and mobilome existed between water and sediment in the Ili River. Specificity-occupancy analysis of the differential resistome and mobilome showed that occurrence frequencies and habitat selections of the differential ARGs shaped the resistome of water and sediment. In contrast, habitat was the main driver that shaped the mobilome in the Ili River.

https://www.sciencedirect.com/science/article/pii/S0147651322007266