Department of Plant Sciences

Iron dynamics in plants results from complex mechanisms involving the integration of transporter activities, with the synthesis of chelating molecules. Under iron deficient conditions, two types of high affinity transport systems are activated, depending on the plant family considered. In non grass plants, Fe(III)-chelate reduction is followed by Fe(II) uptake, whereas in grasses, Fe(III) chelated to secreted phytosiderophores is taken up by roots. Long distance allocation of iron between organs and tissues, as well as its subcellular compartimentation and remobilization, also involve various chelation and reduction activities, associated to transporters and to soluble proteins storing and buffering this metal. This iron trafficking at the whole plant, cellular, and sub-cellular levels, is a highly regulated process starting to be characterized at a molecular level. To maintain iron homeostasis is an important determinant to build up prosthetic groups such as heme and Fe-S clusters, and to assemble them into apoproteins. Such processes require complex protein machineries which are mitochondria and plastids located. An essential, and plant specific, role of these iron dynamics is evidenced by the strong iron requirement for the photosynthetic reaction to take place.