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First published online April 9, 2008; 10.1104/pp.108.118612 Plant Physiology 147:897-911 (2008) © 2008 American Society of Plant Biologists OPEN ACCESS ARTICLE
Differential Regulation of the Expression of Two High-Affinity Sulfate Transporters, SULTR1.1 and SULTR1.2, in Arabidopsis1,[W],[OA]Biochimie et Physiologie Moléculaire des Plantes (H.R., J.-C.D., P.F., P.B.), and Polymorphismes d'Intérêt Agronomique (R.A.), Unité Mixte de Recherche, Montpellier SupAgro/CNRS/INRA, Université Montpellier II, 34060 Montpellier cedex 1, France; Department of Plant Molecular Biology, University of Lausanne, CH–1015 Lausanne, Switzerland (H.R., B.A.); and Heidelberg Institute of Plant Sciences, University of Heidelberg, 69120 Heidelberg, Germany (M.W., R.H.)
The molecular mechanisms regulating the initial uptake of inorganic sulfate in plants are still largely unknown. The current model for the regulation of sulfate uptake and assimilation attributes positive and negative regulatory roles to O-acetyl-serine (O-acetyl-Ser) and glutathione, respectively. This model seems to suffer from exceptions and it has not yet been clearly validated whether intracellular O-acetyl-Ser and glutathione levels have impacts on regulation. The transcript level of the two high-affinity sulfate transporters SULTR1.1 and SULTR1.2 responsible for sulfate uptake from the soil solution was compared to the intracellular contents of O-acetyl-Ser, glutathione, and sulfate in roots of plants submitted to a wide diversity of experimental conditions. SULTR1.1 and SULTR1.2 were differentially expressed and neither of the genes was regulated in accordance with the current model. The SULTR1.1 transcript level was mainly altered in response to the sulfur-related treatments. Split-root experiments show that the expression of SULTR1.1 is locally regulated in response to sulfate starvation. In contrast, accumulation of SULTR1.2 transcripts appeared to be mainly related to metabolic demand and is controlled by photoperiod. On the basis of the new molecular insights provided in this study, we suggest that the expression of the two transporters depends on different regulatory networks. We hypothesize that interplay between SULTR1.1 and SULTR1.2 transporters could be an important mechanism to regulate sulfate content in the roots.
1 This work was supported by grants from the French minister of agriculture (Institut National de la Recherche Agronomique-INRA and Centre International d'Etudes Supérieures en Sciences Agronomiques-Montpellier SupAgro), the French minister of research (Centre National de la Recherche Scientifique-CNRS), and a fellowship granted by the Tunisian government to H.R. 2 Present address: Department of Plant Molecular Biology, Biophore, University of Lausanne, CH–1015 Lausanne, Switzerland. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Hatem Rouached (hatem.rouached{at}unil.ch). [W] The online version of this article contains Web-only data. [OA] Open Access articles can be viewed online without a subscription. www.plantphysiol.org/cgi/doi/10.1104/pp.108.118612 * Corresponding author; e-mail hatem.rouached{at}unil.ch. Received March 3, 2008; accepted April 2, 2008; published April 9, 2008. This article has been cited by other articles:
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