Natural Resistance-Associated Macrophage Proteins (NRAMPs): Functional Significance of Metal Transport in Plants

In plants, there are several families of metal transporters that play an important role in metal uptake and sequestration, thus protecting the plant from stress due to heavy metals. Crop plants grown on heavy metal-contaminated agricultural land present an indirect hazard to the health of their consumers. Hence, it is very important to study the transporters associated with metal transport in plants. Natural resistance-associated macrophage protein (NRAMP) transporters are present in a wide range of organisms. This family of NRAMP transporters has been identified and functionally characterized in several plant species like Arabidopsis, rice, soya bean, etc. that is, in both monocot and dicot plants. In plants, several members of the NRAMP gene family have been identified and functionally characterized. They are involved in the transport of several divalent metal ions in the plant based on their localization. The presence of NRAMP transporter genes has also been computationally predicted in the genomes of all the plants studied so far. This chapter discusses the general properties, structure, function, and expression of NRAMP transporters in several plants based on existing literature. It mainly focuses on the functional significance of the NRAMP family of transporters in both monocot and dicot plants.