3.A.10.1.21
Pyrophosphate-energized vacuolar membrane proton pump 1 (BnVP1) of 763 aas and about 15 - 17 TMSs., possibly in a 5 + 6 + 5 TMS arrangement.  Plants have developed defense mechanisms against cadmium (Cd) stress, with vacuolar compartmentalization of Cd²⁺ being a crucial process in Cd detoxification. The transport of Cd into vacuoles by these cation / H⁺ antiporters is powered by the pH gradient created by proton pumps (Zhu et al. 2024).  BnVP1 expression was significantly higher in ramie roots than in shoots. Cd treatments markedly induced BnVP1 expression in both roots and leaves of ramie seedlings, with a more pronounced effect in roots. Additionally, BnVP1 expression was significantly upregulated by the plant hormone methyl jasmonate (MeJA). Heterologous expression of BnVP1 in transgenic Arabidopsis significantly enhanced V-PPase activity in the roots. The growth performance, root elongation, and total chlorophyll content of transgenic plants with high tonoplast H⁺-PPase (V-PPase) activity were superior to those of wild-type plants. Overexpression of BnVP1 reduced membrane lipid peroxidation and ion leakage, and significantly increased Cd accumulation in the roots of transgenic Arabidopsis seedlings (Zhu et al. 2024). BnVP1 confers cadmium tolerance in Arabidopsis thaliana.