Iron-Requiring Enzymes in the Spotlight of Oxygen

Iron (Fe) is a cofactor required for a variety of essential redox reactions in plant metabolism. Thus, plants have developed a complex network of interacting pathways to withstand Fe deficiency, including metabolic reprogramming. This opinion aims at revisiting such reprogramming by focusing on: (i) the functional relation- ships of Fe-requiring enzymes (FeREs) with respect to oxygen; and (ii) the progression of FeREs engagement, occurring under Fe deficiency stress. In particular, we consideredsuch progression ofFeREsengagement asstrainresponsesofincreas- ing severity during the stress phases of alarm, resistance, and exhaustion. This approachcancontributetoreconcilethevarietyofexperimentalresultsobtainedso far from different plant species and/or different Fe supplies.