Ecotoxicology and Environmental Safety (Sep 2022)
Metagenomic binning and assembled genome analysis revealed the distinct composition of resistome and mobilome in the Ili River
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.
