Membrane Transporter Families of Metal Microelements make Plants GrowBetter and Healthier

Appropriate supplies of metal microelements, such as Fe, Mn, Cu, Zn, Mo, are essential for plant normal growth and development. Plants can also uptake toxic metals, such as Cd, Pb, Hg, when they are exposed to contaminated soils. In response to external fluctuations of these metal element supplies, plants have developed an active and complex network of membrane transport system for optimizing the nutrient uptake, translocation and compartmentalization to maintain their cellular homeostasis. The application of powerful genetic and molecular techniques has contributed a lot to the identification and characterization of gene families that are involved in membrane transport of metal elements. In this review, we summarized recent advances in the functional analysis of transporters involved in the essential metal microelements as well as the toxic metals, including ZIPs, MTPs, HMAs, NRAMPs and YSLs, in both dicot Arabidopsis and monocot rice together with other plants especially the metal hyper-accumulating plants. Well understanding of this complicated but effective membrane transport system provides us a foundation for the development of novel strategies to increase the acquisition and distribution of beneficial elements for crop production as well as the efflux and sequestration of toxic elements for human health.