Arabidopsis Biological Resource Center

Ploidy: 2

Phenotype: Vacuolar H+/Ca2+ transporter; play a central role in Ca2+ and metal sequestration into the vacuole, localized in the tonoplast; predominately expressed in leaves. Altered plant development: alterations in lateral root growth (seedlings display 11% reduction in primary root length when grown on normal medium, number of lateral roots is reduced by 25%, length of the lateral roots is reduced by almost 50%); alterations in apical dominance (reduced branching, reduced length of the secondary inflorescences); delayed flowering; reduced plant height; eventually plants grow and produce seeds normally. Enhanced growth under Mn2+ and Mg2+ stress conditions; perturbed hormone sensitivities (roots are resistant to auxin but are tolerant to 1-aminocycloproprane-1-carboxylic acid (an ethylene precursor), abscisic acid, and benzyladenine; sensitive to gibberellic acid and epibrassinolide); modestly sensitive to exogenous Ca2+; exhibit a 50% reduction in tonoplast Ca2+/H+ antiport activity, a 40% reduction in tonoplast V-type H+-translocating ATPase activity, a 36% increase in tonoplast Ca2+-ATPase activity; high capacity transporter responsible for maintaining low cytosolic-free Ca2+ concentrations in plant cells by catalyzing pH gradient-energized vacuolar Ca2+ accumulation.