Rhizosphere Microbiome-Root Exudate Synergy in Pteris vittata: Coordinated Arsenic Speciation and Multielement Metabolic Coupling Drive Hyperaccumulation Efficiency.

Abstract

Rhizosphere microorganisms play a pivotal role in enhancing the arsenic (As) remediation efficiency of Pteris vittata. However, the interactions among rhizosphere microorganisms, root exudates, and As, as well as their influence on As uptake by Pteris vittata at different As concentrations, remain poorly understood. This study systematically elucidates the molecular-ecological mechanisms through which Pteris vittata facilitates arsenic (As) remediation within a multidimensional interaction network. It was found that the rhizosphere microbial community was dominated by Proteobacteria, Acidobacteriota, and Ascomycota, with 44 bacterial and 10 fungal genera identified as genetically conserved core microorganisms. Microbial-mediated arsenic (As) methylation and reduction processes, coupled with metabolic pathways such as carbon fixation, sulfur oxidation, and phosphorus mineralization, contribute to the formation of an "As-multielement cycling" synergy. This synergy drives As speciation transformation and enhances plant uptake. Root exudates, such as L-phenylalanine and citric acid, enhance arsenic (As) activation and detoxification by selectively recruiting functional microbes, including Sphingomonas carrying arsC. The resulting metabolite profiles exhibit soil-specific response patterns. High As stress shifted microbial community assembly from stochastic to deterministic processes while maintaining remediation efficiency through enhanced fungal network stability (increased average connectivity). These findings reveal the dual "genetic conservation-environmental adaptation" regulatory strategy of Pteris vittata, providing both theoretical and practical foundations for designing targeted rhizosphere microecological technologies to enhance the phytoremediation of arsenic (As)-contaminated soils.