Arsenate reductase critical for arsenic tolerance (PubMed:25099865). Reduces arsenate to arsenite in the root, facilitating efflux of arsenic back into the soil to limit both its accumulation in the root and transport to the shoot (PubMed:25464340). Essential for arsenite efflux from the root, but not necessary for arsenate uptake (PubMed:25464340). [glutaredoxin]-dithiol + arsenate + glutathione + H(+) = arsenite + glutathionyl-S-S-[glutaredoxin] + H2O Inhibited by trobenzenesulphonic acid (TNBS). Expressed in root hairs, epidermal cells at the surface of the root and in the pericycle within the stele. Up-regulated by arsenate and down-regulated by arsenite. Reduced arsenate resistance and increased accumulation of arsenic in shoots and roots.