Iron transport and signaling in plants.

Cellular and whole organism iron homeostasis must be balanced to supply enough iron for metabolism and to avoid excessive, toxic levels. To perform iron uptake from the environment, iron distribution to various organs and tissues, and iron intracellular compartmentalization, various membranes must be crossed by this metal. The uptake and transport of iron under physiological conditions require particular processes such as chelation or reduction because ferric iron has a very low solubility. The molecular actors involved in iron acquisition from the soil have recently been characterized. A few candidates belonging to various gene families are hypothesized to play major roles in iron distribution throughout the plant. All these transport activities are tightly regulated at transcriptional and posttranslational levels, according to the iron status of the plant. These coordinated regulations result from an integration of local and long-distance transduction pathways.