Cross-Talk between Iron Deficiency Response and Defense Establishment in Plants

Plants are at risk of attack by various pathogenic organisms. During pathogenesis, microorganisms produce molecules with conserved structures that are recognized by plants that then initiate a defense response. Plants also experience iron deficiency. To address problems caused by iron deficiency, plants use two strategies focused on iron absorption from the rhizosphere. Strategy I is based on rhizosphere acidification and iron reduction, whereas Strategy II is based on iron chelation. Pathogenic defense and iron uptake are not isolated phenomena: the antimicrobial phenols are produced by the plant during defense, chelate and solubilize iron; therefore, the production and secretion of these molecules also increase in response to iron deficiency. In contrast, phytohormone jasmonic acid and salicylic acid that induce pathogen-resistant genes also modulate the expression of genes related to iron uptake. Iron deficiency also induces the expression of defense-related genes. Therefore, in the present review, we address the cross-talk that exists between the defense mechanisms of both Systemic Resistance and Systemic Acquired Resistance pathways and the response to iron deficiency in plants, with particular emphasis on the regulation genetic expression.