JXB Advance Access published online on April 23, 2004
Journal of Experimental Botany, doi:10.1093/jxb/erh132
© 2004 by Oxford University Press
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Stavanger University College, School of Technology and Science, Box 8002 Ullandhaug, 4068 Stavanger, Norway
* To whom correspondence should be addressed. E-mail: cathrine.lillo{at}tn.his.no.
In higher plants, nitrate reductase (NR) is inactivated by the phosphorylation of a conserved Ser residue and binding of 14-3-3 proteins in the presence of divalent cations or polyamines. A transgenic Nicotiana plumbaginifolia line (S521) has been constructed where the regulatory, conserved Ser 521 of tobacco NR (corresponding to Ser 534 in Arabidopsis) was mutated into Asp. This mutation resulted in the complete abolition of activation/inactivation in response to light/dark transitions or other treatments known to regulate the activation state of NR. Analysis of the transgenic plants showed that, under certain conditions, when whole plants or cut tissues are exposed to high nitrate supply, post-translational regulation is necessary to avoid nitrite accumulation. Abolition of the post-translational regulation of NR also results in an increased flux of nitric oxide from the leaves and roots. In view of the results obtained from examining the different transgenic N. plumbaginifolia lines, compartmentation of nitrate into an active metabolic pool and a large storage pool appears to be an important factor for regulating nitrate reduction. The complex regulation of nitrate reduction is likely to have evolved not only to optimize nitrogen assimilation, but also to prevent and control the formation of toxic, and possibly regulatory, products of NR activities. Phos phorylation of NR has previously been found to influence the degradation of NR in spinach leaves and Arabidopsis cell cultures. However, experiments with whole plants of N. plumbaginifolia, Arabidopsis, or squash are in favour of NR degradation being the same in light and darkness and independent of phosphorylation at the regulatory Ser.
© 2004 Society for Experimental Biology
FOCUS PAPER
Mechanism and importance of post-translational regulation of nitrate reductase
2 Unité de Nutrition Azotée des Plantes INRA, F-78026 Versailles Cedex, France
Abstract 
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  R. Huanosto Magana, S. Adamowicz, and L. Pages Diel changes in nitrogen and carbon resource status and use for growth in young plants of tomato (Solanum lycopersicum) Ann. Bot., May 1, 2009; 103(7): 1025 - 1037. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Shen and S. C. Huber Polycations Globally Enhance Binding of 14-3-3{omega} to Target Proteins in Spinach Leaves Plant Cell Physiol., June 1, 2006; 47(6): 764 - 771. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 U. S. Lea, M.-T. Leydecker, I. Quillere, C. Meyer, and C. Lillo Posttranslational Regulation of Nitrate Reductase Strongly Affects the Levels of Free Amino Acids and Nitrate, whereas Transcriptional Regulation Has Only Minor Influence Plant Physiology, March 1, 2006; 140(3): 1085 - 1094. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. YANG and D. J. MIDMORE A Model for the Circadian Oscillations in Expression and Activity of Nitrate Reductase in Higher Plants Ann. Bot., November 1, 2005; 96(6): 1019 - 1026. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Chivasa, B. K. Ndimba, W. J. Simon, K. Lindsey, and A. R. Slabas Extracellular ATP Functions as an Endogenous External Metabolite Regulating Plant Cell Viability PLANT CELL, November 1, 2005; 17(11): 3019 - 3034. [Abstract] [Full Text] [PDF]
|
|