Arabidopsis IRT2 gene encodes a root‐periphery iron transporter

• Published in: The Plant journal : for cell and molecular biology 2001-04, Vol.26 (2), p.181-189
• Main Authors: Vert, Grégory, Briat, Jean‐François, Curie, Catherine
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis thaliana; Artificial Gene Fusion; Biological and medical sciences; Blotting, Northern; Cadmium; Cadmium - pharmacology; Carrier Proteins; Carrier Proteins - classification; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cation Transport Proteins; Cloning, Molecular; DNA Primers; DNA, Complementary; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant; Glutamate-Ammonia Ligase; Glutamate-Ammonia Ligase - genetics; Iron; Iron - metabolism; iron transporter; iron uptake; IRT; IRT1 gene; IRT2 gene; Life Sciences; Molecular Sequence Data; Plant physiology and development; Plant Proteins; Plant Roots; Plant Roots - cytology; Plant Roots - metabolism; Plants, Genetically Modified; Promoter Regions, Genetic; root; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; transport; Vegetal Biology; Water and solutes. Absorption, translocation and permeability; Zinc; Zinc - metabolism
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1046/j.1365-313x.2001.01018.x

Summary Iron uptake from the soil is a tightly controlled process in plant roots, involving specialized transporters. One such transporter, IRT1, was identified in Arabidopsis thaliana and shown to function as a broad‐range metal ion transporter in yeast. Here we report the cloning and characterization of the IRT2 cDNA, a member of the ZIP family of metal transporters, highly similar to IRT1 at the amino‐acid level. IRT2 expression in yeast suppresses the growth defect of iron and zinc transport yeast mutants and enhances iron uptake and accumulation. However, unlike IRT1, IRT2 does not transport manganese or cadmium in yeast. IRT2 expression is detected only in roots of A. thaliana plants, and is upregulated by iron deficiency. By fusing the IRT2 promoter to the uidA reporter gene, we show that the IRT2 promoter is mainly active in the external cell layers of the root subapical zone, and therefore provide the first tissue localization of a plant metal transporter. Altogether, these data support a role for the IRT2 transporter in iron and zinc uptake from the soil in response to iron‐limited conditions.