Slope gradient and slope position shape soil microbial communities and antibiotic resistance gene structure in gently sloping arable land

Soil is an important reservoir of ARGs and gently sloping arable land is one of the most important land resources for crop production and food security. The effects of slope gradient and slope position as important variables affecting gently sloping arable soils on ARGs are not well understood. In this study, metagenomics was used to investigate the diversity and abundance of ARGs and bacterial communities in soils of five different slope gradients and two slope positions. High diversity of ARGs (20 ARG types containing 659 subtypes) were identified in all slopes, with multidrug resistance and antibiotic efflux being the predominant resistance class and mechanism respectively, suggesting . 17 bacterial genera were identified as potential ARGs hosts, and 5 soil chemical properties were significantly correlated with soil bacteria communities. SEM analysis further reveals that the main driving factor of ARGs is soil physicochemical properties, while bacterial diversity has a negative effect on ARGs abundance. Our results deepen the understanding of the differences in the distribution structure of ARGs in gentle slope cultivated soil, and emphasize that the types and distribution of ARGs may vary with slope gradient and position.