IAR4 mutation enhances cadmium toxicity by disturbing auxin homeostasis in Arabidopsis thaliana.

Cadmium (Cd) is highly toxic to plants, but the targets and modes of toxicity remain unclear. We isolated a Cd-hypersensitive mutant of Arabidopsis thaliana, Cd-induced short root 2 (cdsr2), in the background of the phytochelatin synthase-defective mutant cad1-3. Both cdsr2 and cdsr2 cad1-3 displayed shorter roots and were more sensitive to Cd than their respective wild type.