Effects of predatory mite biocontrols on the dispersal of antibiotic resistomes and virulence factors in tea garden soils

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BACKGROUND: Biocontrols can be used to manage pests while supporting soil health. However, the effects of the biocontrols such as predatory mites on antibiotic resistance in bacterial communities remains largely unknown. Here, we examined long-term field experiments in tea garden soils, combined with global datasets and soil microcosm experiments, to explore the effects and underlying mechanisms of predatory mite treatment on the abundance of antibiotic resistance genes (ARGs) and virulence factor genes (VFGs). RESULTS: Predatory mite treatment may intensify the predation pressure exerted by bacterial predators on bacterial communities through trophic cascades. This led to genome streamlining and alterations in microdiversity and functions within the bacterial communities. In this process, members of the phylum Actinobacteriota, especially the family Pseudonocardiaceae, demonstrated greater adaptability, with their relative abundance increasing from 25.0 to 41.8%, due to their higher nucleotide diversity and growth rates compared to other bacterial taxa. These taxa served as the primary hosts for ARGs and VFGs, which were also identified in global datasets, playing a key role in promoting the abundance of ARGs and VFGs in soil ecosystems. The possibility of trophic cascade effects of predatory mites on the dispersal of ARGs and VFGs were further validated through soil microcosm experiments. CONCLUSIONS: These findings advance our understanding of bacterial evolutionary trajectories under biocontrols, which is crucial for slowing the spread of antibiotic resistance and promoting sustainable agriculture. Video Abstract.