A novel gene from the hyperaccumulator redistributes cadmium and increases its accumulation in transgenic .

A cadmium (Cd) tolerance protein () involved in the response to Cd stress was identified. However, the mechanism underlying the Cd detoxification and accumulation mediated by in plants remains unclear. We compared wild-type (WT) and -overexpressing transgenic poplars in terms of Cd accumulation, physiological indices, and the expression profiles of transporter genes following with 100 μmol/L CdCl. Compared with the WT, significantly more Cd accumulated in the above-ground and below-ground parts of the -overexpressing lines after 100 μmol/L CdCl treatment. The Cd flow rate was significantly higher in the transgenic roots than in the WT roots. The overexpression of resulted in the subcellular redistribution of Cd, with decreased and increased Cd proportions in the cell wall and the soluble fraction, respectively, in the roots and leaves. Additionally, the accumulation of Cd increased the reactive oxygen species (ROS) content. The activities of three antioxidant enzymes (peroxidase, catalase, and superoxide dismutase) increased significantly in response to Cd stress. The observed increase in the titratable acid content in the cytoplasm might lead to the enhanced chelation of Cd. The genes encoding several transporters related to Cd transport and detoxification were expressed at higher levels in the transgenic poplars than in the WT plants. Our results suggest that overexpressing in transgenic poplar plants promotes Cd accumulation, modulates Cd distribution and ROS homeostasis, and decreases Cd toxicity organic acids. In conclusion, genetically modifying plants to overexpress may be a viable strategy for improving the phytoremediation of Cd-polluted soil.