Transgenic tobacco plants expressing ectopically wheat H+-pyrophosphatase (H+-PPase) gene TaVP1 show enhanced accumulation and tolerance to cadmium

Cadmium (Cd) is considered an extremely significant pollutant due to its high toxicity to many organisms. Plants have evolved several mechanisms to cope with Cd, the most important of which is vacuolar sequestration. Cadmium can be directly transported into vacuoles by cations/H+ exchangers, such as CAXs, which are energized by the pH gradient established by proton pumps. A cDNA (TaVP1) encoding wheat vacuolar H+-pyrophosphatase (V-H-PPase) was ectopically expressed in transgenic tobacco to evaluate whether this proton pump expression would enhance Cd tolerance and accumulation in planta. When TaVP1-expressing plants were exposed to various concentrations of Cd, they were found to be more tolerant to Cd compared to wild type plants. Cadmium accumulation in the plant biomass in transgenic plants was higher than that in wild type plants. To the best of our knowledge, this is the first report on the potential for enhancing proton pump expression as a strategy to improve Cd tolerance and accumulation in plants.