Fig. 7. The proposed role of Fe homeostasis in plant defense responses. Pathogen attack elicits the targeted Fe redistribution to the apoplast, which leads to Fe deficiency in the cytosol of attacked cells. The accumulated apoplastic Fe mediates the oxidative burst, which further stimulates Fe efflux and intracellular Fe deficiency. H2O2 and Fe deficiency induce expression of defense-related genes while suppressing the expression of Fe storage-related genes.