The physiological and molecular mechanisms of zinc uptake, transport, and hyperaccumulation in plants: A review

Zinc (Zn) is an essential plant element, but it is toxic to plants in excess. Plants have complicated Zn transport and regulation systems to maintain a proper intracellular concentration of zinc. Some genes have been indentified in plants encoding proteins with putative roles in Zn transport, such as ZIP (Zinc-regulated transporters, Iron-regulated transporter-like Protein), Nramp (Natural resistance-associated macrophage proteins), PIB-type heavy metal associated domain containing ATPases, cation diffusion facilitator (CDF), and Mg2+/H+ exchanger (MHX). The quantitative trail loci (QTL) analysis is being used to find the loci controlling Zn accumulation in heavy metal hyperaccumulator Thlaspi caerulescens or Arabidopsis halleri. Some QTLs associated with plant mortality and leaf bronzing are detected in Zn deficient rice plants.