Wetland plant rhizospheres as selective hotspots for antibiotic resistance genes under microplastic influence

Wetland plant rhizospheres are active interfaces where pollutants, microbial hosts, and antibiotic resistance genes (ARGs) interact, but their role in environmental resistomes remains unclear. We collected paired rhizosphere and bulk soils associated with five wetland plant species from urban riverine wetlands and integrated 16S rRNA gene amplicon sequencing, metagenomic annotation, viral sequence profiles, and microplastic measurements. Rhizosphere soils contained higher total bacterial ARG abundance than bulk soils, consistent with selective enrichment of specific ARG subtypes. Enrichment varied among plants, with the Hemerocallis fulva rhizosphere showing the broadest enrichment and containing representative Rank I high-risk ARGs. MAG-based annotations suggested potential associations among ARG-carrying hosts, mobile genetic elements, and host-linked viruses, although these predictions do not demonstrate active transfer. Viral ARG enrichment was more species-specific and occurred mainly in H. fulva, suggesting plant-dependent virus-host associations. Total microplastic abundance was positively associated with bacterial ARG abundance in both compartments, whereas viral ARG abundance showed nonlinear relationships. Associations with selected polymer types, particle-size fractions, and soil variables (pH, TC, TN, TOC, and Cu) differed between bacterial and viral ARGs and between compartments. These findings reveal plant-specific rhizosphere ARG patterns associated with multiple microplastics and soil environmental variables.