Reductive soil disinfestation and hydrothermal biochar regulate antibiotic resistance mechanisms by reshaping soil...

The health risk posed by antibiotic resistance genes (ARGs) in agricultural soils has become a growing concern. However, a systematic understanding of how microbial life history strategies, functional traits, and community interactions jointly shape ARG dynamics remains lacking. This knowledge gap not only constrains our ability to elucidate the evolutionary mechanisms underlying microbial resistance but also hampers the precise prediction and effective management of soil ARG risks. Here, we established distinct soil habitats through diverse soil managements, including control (CK), reductive soil disinfestation (RSD), and RSD combined with hydrothermal biochar application (HCR), to investigate how microbial traits and interactions shape ARG resistance mechanisms using metagenomic analyses. Our results showed that RSD and HCR treatments significantly reduced the overall abundance and ecological risk of ARGs compared to CK. In CK soils, microbial communities characterized by intensive interactions, high metabolic activity, and rapid growth efficiency promoted the enrichment of ARGs conferring resistance via antibiotic target alteration, protection, or replacement. In contrast, RSD/HCR treatments favored slow-growing, functionally complex, and competition-dominated communities, which were enriched in ARGs associated with antibiotic efflux mechanisms. Moreover, ARGs exhibited pronounced co-occurrence patterns with antimicrobial biosynthetic gene clusters in highly competitive environments. Collectively, this study reveals the selective responses of ARG resistance mechanisms to distinct microbial ecological strategies and provides new insights for the precise management of environmental antibiotic resistance risks.