Iron and zinc homeostasis in plants: a matter of trade-offs

Abstract

Iron and zinc are essential micronutrients in plants, which have evolved homeostatic mechanisms to ensure a proper balance between these two transition metals. However, zinc excess causes toxicity symptoms linked to secondary iron deficiency in shoots of Arabidopsis. Stanton et al. (2023) show that these symptoms are attenuated in a btsl1/btsl2 (BRUTUS-LIKE E3 ligase) double mutant, which is defective for negative regulation of the iron deficiency response believed to protect the plant against the deleterious effect of iron overload. These findings suggest that a trade-off exists between ensuring proper iron nutrition and protecting against zinc excess in Arabidopsis.