Molecular mechanisms of zinc uptake and translocation in rice

Abstract

Zinc (Zn) is an essential micronutrient for plants and humans, involved in protein, nucleic acid, carbohydrate, and lipid metabolism. In addition, Zn is critical to the control of gene transcription and the coordination of other biological processes. Zn deficiency is one of the most serious problems in plant and human nutrition. Like other plants, rice plant acquires Zn from soil and transports it to vegetative tissue as well as seed through a number of transporters which are strictly regulated. Several members of the Zn-regulated transporters and iron (Fe)-regulated transporter-like protein (ZIP) gene family have been characterized and shown to be involved in metal uptake and transport in rice. The most characterized members of this family in rice are OsZIP1, OsZIP3, OsZIP4, OsZIP5, and OsZIP8, however little is known about the expression of these genes through different growth stages of rice. Here we discuss the molecular mechanisms of Zn transport in rice as an essential advance for understanding and manipulating the Zn absorption and translocation in rice. OsZIP1 and OsZIP3 seems important for Zn uptake from soil, OsZIP4, OsZIP5 and OsZIP8 for root to shoot translocation, while OsZIP4 and OsZIP8 seems particularly important for Zn transport to seed.