Transgenic tobacco plants expressing a P1B-ATPase gene from Populus tomentosa Carr. (PtoHMA5) demonstrate improved cadmium transport

Heavy metal ATPase (HMA) plays an important role in phytoremediation via long-distance transportation from root to shoot. In this report, we identified a heavy metal ATPase gene, PtoHMA5, from Populus tomentosa Carr. Its encoded peptide consists of 967 amino acids and has eight trans-membrane motifs inside. Tobacco plants were transformed with this gene via Agrobacterium tumefaciens-mediated method. After exposure to 50 mg/LCdCl2 for 10 d, the transgenic lines displayed higher cadmium accumulation in leaves than did the wild-type plants with an absolute increase of 25.04%, while the transfer coefficient increased by 16.01%-4325%. Physiological testing including assessment of relative electrolytic leakage (REL), malondialdehyde (MDA) content, and chlorophyll content revealed that the transgenic lines were seriously affected when compared with the wild-type plants. In summary, PtoHMA5 is really involved in cadmium transport from root to shoot but is not associated with the removal of cadmium toxicity. (C) 2018 Published by Elsevier B.V.