DELLA proteins enhance cadmium tolerance by coordinating redox protection and cadmium partitioning in Arabidopsis.

Cadmium (Cd) toxicity requires plants to coordinate growth restraint with cellular protection, but the upstream regulatory mechanism remains unclear. Here, we identify the gibberellin (GA)-DELLA module as a positive regulator of Cd tolerance in Arabidopsis thaliana. Cd exposure reduced endogenous GA levels, shifted GA metabolic gene expression toward a low-GA state, and increased DELLA protein abundance; exogenous GA₃ attenuated this increase. Genetic and pharmacological analyses showed that elevated DELLA activity improved growth under Cd stress, whereas loss of DELLA function increased sensitivity. Mechanistically, DELLA activity strengthened redox protection and restricted root-to-shoot Cd translocation, as indicated by lower reactive oxygen species and lipid peroxidation, higher antioxidant capacity, better maintenance of photosynthetic performance, and enhanced expression of genes associated with Cd chelation and vacuolar sequestration. These results support a model in which a Cd-induced low-GA state promotes DELLA-dependent protection by coordinating oxidative defense with Cd retention in roots.