Insights into the drivers of antibiotic resistance gene migration in soil-lettuce system with manure application from different sources

Abstract

The application of livestock manure serves as a significant source of ARGs in soils. To study the impact of manure application on the migration of ARGs in the soil-plant system, we set different application ratios (1 %, 3 %, 8 %) of chicken and cow manure for treatment. The study's results demonstrated that the application of organic fertilizers increased the quantity of resistance genes in soil, root, and leaf zones. This change was influenced by the type and proportion of the organic fertilizers used. ARGs and MGEs exhibited the highest absolute enrichment levels in leaf tissues (2.53 and 2.01 times, respectively) with the 3 % cow manure treatment. In contrast, chicken manure exhibited the highest enrichment levels after the 1 % addition (2.51 and 1.81 times, respectively). The applied manure exhibited a high degree of similarity in bacterial community composition with the soil-lettuce system, indicating that ARGs may spread through microorganisms in this system. This study demonstrated that the evolution of bacterial community structure plays a pivotal role in mediating and driving the migration of ARGs within manure-amended soil-plant ecosystems, providing a theoretical basis for understanding the transmission of ARGs in soils and plants due to agricultural production activities.