Plant Physiol. Drug Metab Dispos
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on September 22, 2006; 10.1104/pp.106.087510

This Article
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrow All Versions of this Article:
142/3/1075    most recent
pp.106.087510v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Krouk, G.
Right arrow Articles by Gojon, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Krouk, G.
Right arrow Articles by Gojon, A.
Agricola
Right arrow Articles by Krouk, G.
Right arrow Articles by Gojon, A.

Received July 27, 2006
Accepted September 8, 2006

Regulation of the High-affinity NO3- Uptake System by a NRT1.1-mediated "NO3--demand" Signalling in Arabidopsis

Gabriel Krouk , Pascal Tillard , and Alain Gojon *

Biochimie et Physiologie Moléculaire des Plantes, UMR 5004, Agro-M/CNRS/INRA/UM2, Place Viala, 34060 Montpellier Cedex 1, France

* Corresponding author; email: gojon{at}ensam.inra.fr.

The NRT2.1 gene of Arabidopsis thaliana encodes a major component of the root high-affinity NO3- transport system (HATS) that plays a crucial role in NO3- uptake by the plant. Although NRT2.1 was known to be induced by NO3- and feedback-repressed by reduced N metabolites, NRT2.1 is surprisingly up-regulated when NO3- concentration decreases to a low level (<0.5 mM) in media containing a high concentration of NH4+ or glutamine (≥1 mM). The NRT3.1 gene, encoding another key component of the HATS, displays the same response pattern. This revealed that both NRT2.1 and NRT3.1 are co-ordinately down-regulated by high external NO3- availability, through a mechanism independent from that involving N metabolites. We show here that repression of both genes by high NO3- is specifically mediated by the NRT1.1 NO3- transporter. This mechanism warrants that either NRT1.1 or NRT2.1 is active in taking up NO3- in presence of a reduced N source. Under low NO3-/high NH4+ provision, the NRT1.1-mediated repression of NRT2.1/NRT3.1 is relieved, which allows reactivation of the HATS. The analysis of atnrt2.1 mutants showed that this constitutes a crucial adaptive response against NH4+ toxicity, since NO3- taken up by the HATS in this situation prevents the detrimental effects of pure NH4+ nutrition. It is thus hypothesized that the NRT1.1-mediated regulation of NRT2.1/NRT3.1 is a mechanism aiming to satisfy a specific "NO3- demand" of the plant, in relation with the various specific roles that NO3- plays, in addition of being a N source. A new model is proposed for regulation of the HATS, involving both feed-back repression by N metabolites and NRT1.1-mediated repression by high NO3-.




This article has been cited by other articles:


Home page
 Plant Physiol.Home page
S. Kant, Y.-M. Bi, E. Weretilnyk, S. Barak, and S. J. Rothstein
The Arabidopsis Halophytic Relative Thellungiella halophila Tolerates Nitrogen-Limiting Conditions by Maintaining Growth, Nitrogen Uptake, and Assimilation
Plant Physiology, July 1, 2008; 147(3): 1168 - 1180.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
J. Wirth, F. Chopin, V. Santoni, G. Viennois, P. Tillard, A. Krapp, L. Lejay, F. Daniel-Vedele, and A. Gojon
Regulation of Root Nitrate Uptake at the NRT2.1 Protein Level in Arabidopsis thaliana
J. Biol. Chem., August 10, 2007; 282(32): 23541 - 23552.
[Abstract] [Full Text] [PDF]

Home page
 J Exp BotHome page
A. J. Miller, X. Fan, M. Orsel, S. J. Smith, and D. M. Wells
Nitrate transport and signalling
J. Exp. Bot., July 1, 2007; 58(9): 2297 - 2306.
[Abstract] [Full Text] [PDF]

Home page
 J Exp BotHome page
E. Fernandez and A. Galvan
Inorganic nitrogen assimilation in Chlamydomonas
J. Exp. Bot., July 1, 2007; 58(9): 2279 - 2287.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2006 by the American Society of Plant Biologists