Journal of Biological Chemistry
Volume 278, Issue 48, 28 November 2003, Pages 47644-47653
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Membrane Transport, Structure, Function, and Biogenesis
Expression Profiles of Arabidopsis thaliana in Mineral Deficiencies Reveal Novel Transporters Involved in Metal Homeostasis*

https://doi.org/10.1074/jbc.M309338200Get rights and content
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Plants directly assimilate minerals from the environment and thus are key for acquisition of metals by all subsequent consumers. Limited bio-availability of copper, zinc and iron in soil decreases both the agronomic productivity and the nutrient quality of crops. Understanding the molecular mechanisms underlying metal homeostasis in plants is a prerequisite to optimizing plant yield and metal nutrient content. To absorb and maintain a balance of potentially toxic metal ions, plants utilize poorly understood mechanisms involving a large number of membrane transporters and metalbinding proteins with overlapping substrate specificities and complex regulation. To better understand the function and the integrated regulation, we analyzed in Arabidopsis the expression patterns in roots and in leaves of 53 genes coding for known or potential metal transporters, in response to copper, zinc, and iron deficiencies in Arabidopsis. Comparative analysis of gene expression profiles revealed specific transcriptional regulation by metals of the genes contrasting with the known wide substrate specificities of the encoded transporters. Our analysis suggested novel transport roles for several gene products and we used functional complementation of yeast mutants to correlate specific regulation by metals with transport activity. We demonstrate that two ZIP genes, ZIP2 and ZIP4, are involved in copper transport. We also present evidence that AtOPT3, a member of the oligopeptide transporter gene family with significant similarities to the maize iron-phytosiderophore transporter YS1, is regulated by metals and heterologous expression AtOPT3 can rescue yeast mutants deficient in metal transport.

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Supported in part by the Centre National de la Recherche Scientifique and by an Organization for Economic Cooperation and Development fellowship “Cooperative Research Programme: Biological Resource Management For Sustainable Agricultural Systems.”

*

This work was supported by a grant from the Hellmann Family fund, a Faculty Research Grant (University of California, Berkeley), by the Syngenta Agricultural Discovery Institute, and by the International Copper Association. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains Supplemental Table S1.

Current address: Agronomy and Range Science, One Shields Ave., University of California, Davis, CA 95616-8515.