Iron solutions: acquisition strategies and signaling pathways in plants

Iron is an essential nutrient for plants and crucial for a variety of cellular functions. In most soils, iron is present in large quantities, but mainly in forms that are not available to plants. Mobilization of iron by plants is achieved by different strategies, either by secretion of plant-borne chelators or by reductive and proton-promoted processes. These reactions, and subsequent uptake of Fe via specific transporters, are increased when the Fe requirements of the plant are not being met. When iron is taken up in excess of cellular needs, toxic oxygen radicals can form. Therefore, plants must tightly regulate iron levels within the cell. This article presents recent progress towards an integrative picture of how iron is sensed and acquired.