Abstract: Cadmium (Cd²⁺) contamination in agricultural soils poses a critical threat to global food security and plant productivity. This study examined Cd²⁺ contamination in soils irrigated with municipal wastewater near an open disposal site in Raiganj, Uttar Dinajpur, West Bengal, and isolated eleven Cd²⁺-resistant bacterial strains from the rhizosphere of Amaranthus viridis L. Among these, strain AF2 exhibited superior multi-metal resistance and was selected for detailed characterization. 16S rRNA gene sequencing identified AF2 as Pseudomonas aeruginosa, with 100% sequence identity to strains BQ26 and NCTC 13628. Growth kinetics in Cd²⁺-amended LB medium revealed concentration-dependent growth delays, while biofilm formation was stimulated at low Cd²⁺ levels (up to 1 mM) but inhibited at higher concentrations. SEM-EDAX analysis confirmed Cd²⁺ bioadsorption via multiple binding sites on the cell wall. AF2 also exhibited diverse plant growth-promoting (PGP) traits, including IAA production, ACC deaminase activity, nitrogen fixation, siderophore production, phosphate solubilization, and Zn solubilization, as well as ammonia and HCN production. In vitro application of AF2 significantly enhanced germination (1.1 to 8-fold), root growth (1.5 to 3.3-fold), fresh weight (1.3 to 1.8-fold), dry weight (1.4 to 2.2-fold), and root-to-shoot ratio of A. viridis seedlings under Cd²⁺ stress. These findings highlight AF2 as a potent bioremediation agent and biofertilizer, capable of mitigating heavy metal toxicity while improving crop yields in contaminated agroecosystems.

Keywords: Heavy metal, Cadmium toxicity, Plant growth promotion, bioremediation, Pseudomonas aeruginosa strain AF2, Amaranthus viridis L., IAA, siderophore, ACC deaminase.

Downloads: | DOI: 10.17148/IARJSET.2026.13160