Interactions between antibiotic resistance genes and soil environmental factors: Coupling, antagonism, and synergism

Abstract

The soil environment is crucial for maintaining the stability of ecosystems and the health of organisms. Due to the extensive use of antibiotics, antibiotic resistance genes (ARGs) have become pervasive soil contaminants. ARGs can spread through horizontal gene transfer mediated by mobile genetic elements and vertical transfer mediated by microbial proliferation, driving the expansion of resistant microbiota and novel variants of ARGs. Although ARGs have multifaceted impacts on soil properties, the dynamics, site-specificity, ecological complexity and heterogeneity of the soil environment obscure the underlying interaction mechanisms. This review systematically analyzes the sources, transmission pathways and environmental drivers of ARGs, and interprets their complex interactions with soil parameters. Interdependent factors such as soil pH, organic matter, moisture and microbial communities bidirectionally regulate ARGs distribution via physicochemical modulation and microbial community restructuring. Heavy metals promote the proliferation of ARGs via co-selection and oxidative stress mechanisms, in contrast to the antagonistic effects of enzymatic degradation on ARGs. Niche differentiation underlies the varied impacts of soil biota (fauna/flora) and soil physicochemical properties on ARGs, highlighting environment-dependent synergistic-antagonistic interactions. Based on this, we propose a remediation framework to address ARGs pollution. Priority research directions include: (1) spatiotemporal dynamics of the feedback loop between ARGs and the environment; (2) quantitative modeling of the coupling effects of multiple factors; (3) precision mitigation strategies targeting niche-specific transmission hotspots.