Plant Oxidative Stress Mediates the Synergistic Transformation of Benzotriazole Ultraviolet Stabilizers in Rhizosphere Soil: Insights from Dual Exposure Pathways

Abstract

Benzotriazole ultraviolet stabilizers (BUVs) are widespread emerging contaminants in soil. However, their transformation in the rhizosphere and the regulatory effects of plant oxidative stress on rhizosphere remediation remain unclear. The objective of this study was to investigate these effects using molecular simulations and rhizosphere and foliar exposure experiments. The removal efficiency of the four BUVs was 15–46% higher in the rhizosphere of Helianthus annuus than under natural soil degradation. The plant rhizosphere promoted BUV desorption from soil and induced hydroxylation as a specific transformation pathway. Direct rhizosphere exposure triggered oxidative stress and accelerated reactive oxygen species (ROS) accumulation in soil. Rhizosphere ROS contributed approximately 31.2%–42.7% to BUV transformation. Foliar exposure experiments suggested that plant oxidative stress is an important contributor to rhizosphere ROS generation. Under BUV stress, plant oxidative stress regulated the composition of dissolved organic matter (DOM) and the selective enrichment of bacteria, including Acidobacteriota, Actinomycota, and Bacteroidota. Multivariate correlation network analysis suggested that foliar exposure resulted in more complex interactions among rhizosphere microenvironmental characteristics than did direct rhizosphere exposure. This study provides insights into BUV transformation in the rhizosphere and establishes a framework for plant signal-guided rhizosphere remediation strategies.