The Molecular Genetics of Zinc Uptake and Utilization Efficiency in Crop Plants

Abstract

Zinc (Zn) is an essential micronutrient for plant growth and development, and its deficiency in plants has been widely reported in many regions of the world. About 50% of soil used for agriculture contain a low level of plant-available Zn, which reduces not only yield but also nutritional quality of grains and derivatives. Under these conditions, the Zn utilization efficiency (ZnUE) of plants is essential for food crops and human health. Zn uptake and ZnUE by plants is complex, as each step, including root and foliar uptake, assimilation, translocation, and remobilization are governed by multiple interacting environmental and genetic factors. Zinc transportation from roots to shoots occurs through the xylem and is then easily retranslocated by phloem. The Zn uptake into cells and its permeability into and out of intracellular organelles require some of the specific chemicals generally known as transporter proteins. These proteins possess a quality to span the cell membranes that facilitate the movement of Zn. A number of metal transporters have been identified in plants, including the P1B-ATPase family, zinc-regulated transporter (ZRT), iron-regulated transporter (IRT)-like protein (ZIP), natural resistance-associated macrophage protein (NRAMP) family, and cation diffusion facilitator (CDF or MTP) family. This manuscript critically reviews about Zn transport pathway, molecular genetic driving the Zn uptake, and Zn utilization efficiency in several crop plants.