Proteomic Perspective of Cadmium Tolerance in Strain KDM3 and Its Bioremediation Potential in Rice Ecosystem

In this study, a multi-metal-tolerant natural bacterial isolate strain KDM3 from an industrial effluent in Mumbai, India, showed high cadmium (Cd) tolerance. grew in the presence of more than 100 ppm (880 μM) Cd (LD = 100 ppm) and accumulated Cd intracellularly. Following Cd exposure, a comparative proteome analysis revealed molecular mechanisms underlying Cd tolerance. Among a total of 69 differentially expressed proteins (DEPs) in Cd-exposed cells, induction of operon proteins and L-cysteine/L-cystine shuttle protein FliY was observed, while Dps and superoxide dismutase proteins were overexpressed, indicating upregulation of a robust oxidative stress defense. ENTRA1, a membrane transporter showing homology to heavy metal transporter, was also induced . In addition, the protein disaggregation chaperone ClpB, trigger factor, and protease HslU were also overexpressed. Notably, 46 proteins from the major functional category of energy metabolism were found to be downregulated. Furthermore, the addition of to Cd-spiked soil resulted in a significant reduction in the Cd content [roots (11%), shoot (50%), and grains (46%)] of the rice plants. Cd bioaccumulation of improved plant growth and grain yield. We conclude that , a highly Cd-tolerant bacterium, is an ideal candidate for bioremediation of Cd-contaminated agricultural soils.