A novel gene SpCTP3 from the hyperaccumulator Sedum plumbizincicola redistributes cadmium and increases its accumulation in transgenic Populus × canescens

Abstract

A cadmium (Cd) tolerance protein (SpCTP3) involved in the Sedum plumbizincicola response to Cd stress was identified. However, the mechanism underlying the Cd detoxification and accumulation mediated by SpCTP3 in plants remains unclear. We compared wild-type (WT) and SpCTP3-overexpressing transgenic poplars in terms of Cd accumulation, physiological indices, and the expression profiles of transporter genes following with 100 μmol/L CdCl2. Compared with the WT, significantly more Cd accumulated in the above-ground and below-ground parts of the SpCTP3-overexpressing lines after 100 μmol/L CdCl2 treatment. The Cd flow rate was significantly higher in the transgenic roots than in the WT roots. The overexpression of SpCTP3 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 Cd2+ transport and detoxification were expressed at higher levels in the transgenic poplars than in the WT plants. Our results suggest that overexpressing SpCTP3 in transgenic poplar plants promotes Cd accumulation, modulates Cd distribution and ROS homeostasis, and decreases Cd toxicity via organic acids. In conclusion, genetically modifying plants to overexpress SpCTP3 may be a viable strategy for improving the phytoremediation of Cd-polluted soil.

Exogenous strigolactone improves the cadmium accumulation in Solanum nigrum var. humile

“…humile is a Cd‐hyperaccumlator plant 23 . The Cd ions are separated and immobilized in the cytoplasm of hyperaccumulator plants in the form of relatively stable metal chelates/complexes, whereas exogenous strigolactone may promote the change of the chemical form of Cd, and the specific mechanism of this needs to be further investigated 39 . In addition, exogenous strigolactone decreased the TF of S. nigrum var.…”

Overexpression of ApHIPP26 from the Hyperaccumulator Arabis paniculata Confers Enhanced Cadmium Tolerance and Accumulation to Arabidopsis thaliana

“…According to professional evaluation and analysis, many star plants applied in phytoremediation have been found, and molecular mechanisms and useful candidate genes for the absorption and accumulation of heavy metals have been explored in these plants. In the Populus×canescens line, the CTP3 gene from Sedum plumbizincicola X. H. Guo was overexpressed and increased cadmium tolerance and accumulation, altering the distribution of Cd in leaf tissues [35]. Moreover, RNAi and overexpression techniques proved that SpHMA3 positively regulated Cd accumulation by compartmentalization in Sedum plumbizincicola [36].…”

Genome-wide identification of bHLH gene family and its response to cadmium stress in Populus × canescens

“…P. canescens seedlings, derived from micropropagation ( Li et al, 2023 ), were cultured hydroponically at 25 °C under a photoperiod of 16 h light and 8 h dark within an artificial climate chamber. After acclimatization in half-strength Hoagland nutrient medium for one month, seedlings were treated with 10 µM CdCl 2 to induce Cd stress for 168 h. A concentration of 10 µM CdCl 2 was sufficient to elicit a transcription factor response in P. cansecens without causing harm.…”