Advancing Cadmium Remediation via Rhizosphere Engineering: From Microbial Mechanisms to Field Deployment

Cadmium (Cd) contamination of agricultural soils threatens food security and ecosystem health worldwide, yet conventional cleanup methods remain costly and ecologically damaging. Phytoremediation offers a sustainable in situ alternative, but low metal bioavailability, insufficient plant biomass, and inconsistent microbial performance limit field deployment. This review provides a framework that links molecular plant-microbe interactions to practical rhizosphere engineering for Cd management. We compare how functional traits of plant growth-promoting rhizobacteria (PGPR), arbuscular mycorrhizal fungi (AMF), and endophytes influence Cd mobilization versus immobilization, pH tolerance, and persistence. Their functions overlap and depend on plant species, Cd concentration, soil properties, and microbial strain; nevertheless, the evidence points to general tendencies: PGPR often drive short-term Cd mobilization with limited persistence, AMF commonly promote more durable immobilization through hyphal sequestration, and endophytes frequently modulate internal metal transport. We also evaluate synthetic consortia, multi-omics-guided microbiome design, and soil amendments. Field outcomes are appraised against explicit criteria (trial duration, replication across sites, use of historically contaminated soils, and reporting of Cd removal rate, translocation factor, available soil Cd, biomass, and soil health indicators), which also underpin the proposed standardized validation protocols. Matching microbial traits to site-specific goals, alongside food-safety, cost, and regulatory considerations, can help move phytoremediation toward scalable deployment work provides environmental managers and policymakers with a comprehensive roadmap for sustainable Cd remediation in agricultural landscapes.