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AtDUR3 encodes a new type of high-affinity urea/H+ symporter in Arabidopsis.

Liu, Lai-Hua and Ludewig, Uwe and Frommer, Wolf B. and von Wirén, Nicolaus (2003):
AtDUR3 encodes a new type of high-affinity urea/H+ symporter in Arabidopsis.
15, In: The Plant cell, (3), pp. 790-800, ISSN 1040-4651, [Article]

Abstract

Urea is the major nitrogen form supplied as fertilizer in agricultural plant production but also an important nitrogen metabolite in plants. We report the cloning and functional characterization of AtDUR3, a high-affinity urea transporter in plants. AtDUR3 contains 14 putative transmembrane-spanning domains and represents an individual member in Arabidopsis that belongs to a superfamily of sodium-solute symporters. Heterologous expression in urea uptake-defective yeast as well as two-electrode voltage clamp and uptake studies using (14)C-labeled urea in AtDUR3-expressing oocytes demonstrated that AtDUR3 mediates urea transport. In both heterologous systems, urea transport was stimulated at low pH. In oocytes, inward currents indicated that urea is cotransported with protons. By contrast, a supply of Na(+) ions could not stimulate urea transport. Transport of (14)C-labeled urea by AtDUR3 in oocytes exhibited saturation kinetics with a K(m) of approximately 3 micro M. AtDUR3 was expressed in shoots and roots and upregulated during early germination and under nitrogen deficiency in roots. We propose a role of AtDUR3 in urea uptake by plant cells at low external urea concentrations.

Item Type: Article
Erschienen: 2003
Creators: Liu, Lai-Hua and Ludewig, Uwe and Frommer, Wolf B. and von Wirén, Nicolaus
Title: AtDUR3 encodes a new type of high-affinity urea/H+ symporter in Arabidopsis.
Language: English
Abstract:

Urea is the major nitrogen form supplied as fertilizer in agricultural plant production but also an important nitrogen metabolite in plants. We report the cloning and functional characterization of AtDUR3, a high-affinity urea transporter in plants. AtDUR3 contains 14 putative transmembrane-spanning domains and represents an individual member in Arabidopsis that belongs to a superfamily of sodium-solute symporters. Heterologous expression in urea uptake-defective yeast as well as two-electrode voltage clamp and uptake studies using (14)C-labeled urea in AtDUR3-expressing oocytes demonstrated that AtDUR3 mediates urea transport. In both heterologous systems, urea transport was stimulated at low pH. In oocytes, inward currents indicated that urea is cotransported with protons. By contrast, a supply of Na(+) ions could not stimulate urea transport. Transport of (14)C-labeled urea by AtDUR3 in oocytes exhibited saturation kinetics with a K(m) of approximately 3 micro M. AtDUR3 was expressed in shoots and roots and upregulated during early germination and under nitrogen deficiency in roots. We propose a role of AtDUR3 in urea uptake by plant cells at low external urea concentrations.

Journal or Publication Title: The Plant cell
Volume: 15
Number: 3
Divisions: 10 Department of Biology > Plant Nutrition and Biomass
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10 Department of Biology
Date Deposited: 17 Mar 2010 15:45
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