A novel zinc transporter essential for Arabidopsis zinc and iron-dependent growth

Abstract

Zinc (Zn), an essential micronutrient, is absorbed by plant roots and redistributed to leaves. This process must be finely regulated in order to avoid toxic Zn2+ overaccumulation, which can arise due to Zn2+ oversupply or Zn2+ hyperaccumulation induced by Fe2+ deficiency. Although several proteins in Arabidopsis thaliana are essential for retaining Zn in the root and partitioning it from roots to leaves, how Zn2+ homeostasis in leaves is maintained is largely unknown. In this study, we identified a novel Golgi-localized protein named ZINC NUTRIENT ESSENTIAL1 (AtZNE1,At3g08650) in Arabidopsis. AtZNE1 contains 14 putative transmembrane domains. AtZNE1 promoter has strong activity in the root and leaf. Its expression complemented the increased sensitivity of a yeast mutant to excess Zn2+. The disruption of AtZNE1 in the T-DNA insertion mutant atzne1 caused growth defect under excess-Zn or Fe deficit conditions, but had no effects on the total Zn and Fe contents. We propose that AtZNE1 plays a vital role in plant adaptation to excess Zn or Fe deficiency.