Metal-tolerant Rhizobacteria mediated phytostabilization of heavy metal-contaminated soil: A Review

Abstract

Heavy metal contamination from industrialization, mining, agriculture, and urbanization poses serious threats to ecosystems and human health. Toxic elements such as cadmium (Cd), lead (Pb), mercury (Hg), chromium (Cr), and nickel (Ni) persist in soils, accumulate in food chains, and disrupt ecological balance. Conventional remediation methods, including soil excavation and chemical treatments, are costly, unsustainable, and often damaging to soil quality. Phytoremediation, particularly phytostabilization, offers a promising alternative by using plants and their associated rhizobacteria to immobilize metals in the rhizosphere, reducing mobility and limiting groundwater contamination and food chain transfer. Metal-tolerant rhizobacteria enhance this process by producing siderophores, exopolysaccharides, biofilms, and phytohormones, which improve metal immobilization, plant tolerance, and soil fertility. They also suppress plant pathogens and aid nutrient uptake, further strengthening plant growth in contaminated soils. Despite these benefits, challenges such as poor biomass production, variable soil conditions, and uncertainties regarding long-term effectiveness restrict large-scale application. Future research should focus on optimizing plant-microbe partnerships and understanding their mechanisms under different environmental conditions. Rhizobacteria-assisted phytostabilization thus represents a sustainable, eco-friendly approach for managing heavy metal pollution while supporting soil restoration and agricultural productivity.