Distribution patterns and ecological risks of antibiotic resistance genes in the Yap Trench.

Antibiotic resistance genes (ARGs) are a global environmental concern, yet their vertical distribution in pristine marine ecosystems remains poorly understood. This study investigated the distribution of ARG distribution in both the water column and sediments of the Yap Trench, which reaches depths over 6500 m Results revealed significant variations in ARG diversity and abundance across depths and habitats. The deep-water (DW) zones exhibited the highest diversity (291-472 subtypes) and abundance (1.79 copies/cell), followed by upper-water (UW) zones (240-314 subtypes, 0.31 copies/cell), while sediments had the lowest diversity (72-236 subtypes) and abundance (0.03 copies/cell). The most prevalent resistance genes included those conferring resistance to multidrug, polymyxin, and beta-lactam in the Yap Trench. ARG distribution closely correlated with microbial hosts, including Pseudomonadota, Chloroflexota, Bacteroidota, and Planctomycetota. Risk assessment showed high-risk ARGs were most abundant in DW zones, with pathogenic groups capable of spreading multiple ARGs (e.g., macAB, mexDJKW, mdtE, muxC). This study provides a systematic understanding of the distribution patterns and potential risks of ARGs in the water column and sediments of pristine marine ecosystems, underscoring the penetration of antibiotic pollution into the deep ocean and offering new insights for marine pollution control strategies.