Distribution and relationship of heavy metals, microbial communities and antibiotic resistance genes in the riparian soils of Daye Lake, China.

Abstract

Heavy metals pose ecological and resistome risks to aquatic systems. To comprehensively assess the health status of aquatic ecosystems, it is necessary to quantify the ecological risks of heavy metals in riparian soils and their associations with microbial communities and antibiotic resistance genes (ARGs), yet related evidence was scarce. This study evaluated the potential ecological risk of heavy metal-contaminated riparian soils of Daye Lake, revealed the distribution of bacterial communities and ARGs by high-throughput sequencing techniques, and explored the association between heavy metals and bacterial communities and ARGs. The results showed that As, Cd, Cu, Pb, and Se were the primary polluting metals in the riparian soils of Daye Lake. Microbial community analysis presented that Proteobacteria (31.5%), Actinobacteria (30.3%), and Acidobacteria (14.1%) appeared to be the top three prevalent phylums, and seven pathogenic genera were identified based on VFDB. Correlation analysis showed that 17 bacterial communities among the top 50 bacterial genera had significant negative associations with heavy metals (r < -0.5; P < 0.05), and 10 bacterial communities had significant positive associations with heavy metals (r > 0.5; P < 0.05), indicating that heavy metals could exert co-selection forces on the microbial community. ARGs analysis presented that vancomycin, multidrug, and aminoglycoside resistance genes were the dominant ARGs. The co-occurrence of ARGs, virulence factor genes (VFGs), and mobile genetic elements (MGEs) (r > 0.8; P < 0.05) suggested high transmission risk of ARGs in environments. The significant correlations of heavy metals and ARGs (P < 0.05), co-occurrence of the resistance genes (MRGs) and ARGs (r > 0.8; P < 0.05), and significant associations between the geochemical enrichment of heavy metals and ARGs (P < 0.05) consistently indicated important impacts of heavy metals on environmental resistome risks. This research firstly revealed the associations between heavy metals and microbial communities and ARGs in riparian soils, which offers valuable insights into risk prevention and pollution control of heavy metals in the environment.