Biogeographical pattern of persistent organic pollutant-transformation genes and their hosts across global inland...

Persistent organic pollutants (POPs) remain widespread in inland waters despite decades of regulation, yet the global distribution and ecological controls of microbial POP transformation potential remain largely unresolved. Here, we analyzed 1593 metagenomic samples from inland waters across six continents to investigate the biogeography, microbial hosts, and environmental drivers of POP transformation genes (POPTGs). We identified four major POP categories, with polychlorinated POP transformation genes dominating both water and sediment habitats. Sediments harbored significantly higher POPTG richness and abundance than water columns, highlighting their role as global reservoirs of POP transformation capacity. Unexpectedly, POPTG diversity displayed hump-shaped latitudinal pattern. Proteobacteria were the dominant POPTG carriers, and widespread host taxa generally possessed broader transformation repertoires. Nearly half of POPTG-carrying species were shared between habitats, while frequent associations with mobile genetic elements suggested potential horizontal dissemination of transformation traits. Structural equation modeling revealed that host diversity, anthropogenic pressure, and mean annual temperature collectively explained 38% of POPTG abundance variation, with host diversity exerting the strongest effect. Our findings establish a global framework linking microbial ecology with POP transformation potential and provide insights into predicting natural attenuation and remediation capacity of inland waters under environmental change.