Does argricultural polluted branches contribute to the spread of antibiotic resistance genes in a multi-branch riverine network?

The Jialing River is the second longest and largest basin area tributary of the YangtZe River in China. Most of the areas that the river flows through are agricultural or rural area, which makes the Jialing River an ideal system for gaining insight into how agricultural activities influence the ARGs distribution in the river network. Therefore, a rural section of the Jialing River influenced by intensive agricultural activities was selected. Surface water samples were collected from the upstream, midstream, and downstream of the agricultural area. Sampling was also performed on six branches which are located in the midstream area, and receive wastewater from feedlots, and domestic sewage from scattered rural communities. Recent studies demonstrated that high-throughput quantitative PCR (HT-qPCR) provides a efficient and unbiased strategy for detecting ARGs and MEGs in both cultured or noncultured resistant bacteria in environmental samples . Here, HT-qPCR with 296 validated primer sets which target all major classes of ARGs and MEGs, and 16S rRNA gene-based Miseq sequencing were employed to addressed three key questions: (i) Whether or How agricultural activities influence the spatial distribution, abundance, and composition of ARGs in the river network? (ii) Are the microbial communities correlated with the diversity of ARGs? (iii) Which chemical or biological parameters are correlated with the distribution of ARGs?