To characterize the distribution of antibiotic resistance genes(ARGs) in different types of agricultural soil in highly cultivated hilly areas, the abundance and diversity of ARGs in vegetable, orchard, and arable soils were analyzed in this study. The results showed that 70 ARGs and four mobile genetic elements(MGEs) were detected in all soil samples, with β-lactam cphA-01 being the most abundant genes in the agricultural soils. In vegetable and orchard soils, the main ARG subtypes were cphA-01 and cmx(A) genes, whereas the mexF and aacC genes were predominant in cropland soils. The relative abundance and diversity of soil ARGs showed that cropland<vegetable land<orchard, which was related to the nutrient conditions of different agricultural soils. Similarly, the relative abundance and diversity of MGEs were lowest in cropland, whereas their highest values were detected in vegetable and orchard soils, respectively. The significant positive correlation(P<0.05) between the abundance of soil MGEs and ARGs suggests that horizontal gene transfer may facilitate the spread of antibiotic resistance in the agricultural soils in highly cultivated hilly areas.
Keywords: agricultural land; antibiotic resistance genes(ARGs); high-throughput QPCR(HT-QPCR); highly cultivated hilly areas; mobile genetic elements(MGEs).