OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 18/11/3252    most recent tpc.106.042689v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Martin, A. Articles by Hirel, B. Search for Related Content PubMed PubMed Citation Articles by Martin, A. Articles by Hirel, B. Agricola Articles by Martin, A. Articles by Hirel, B.

Two Cytosolic Glutamine Synthetase Isoforms of Maize Are Specifically Involved in the Control of Grain Production^[W],[OA]

^a Unité de Nutrition Azotée des Plantes UR511, Institut National de la Recherche Agronomique, F-78026 Versailles Cedex, France
^b School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, United Kingdom
^c Laboratoire d'Androgenèse et Biotechnologie, Université de Picardie Jules Verne, Ilot des Poulies, F-80039 Amiens Cedex, France
^d Biogemma, Campus Universitaire des Cézaux, F-63170 Aubière, France
^e Unité Mixte de Recherche de Génétique Végétale, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Université de Paris-Sud, Institut National Agronomique Louis Grignon, F-91190 Gif sur Yvette Cedex, France
^f Departamento Biología Vegetal y Ecología, Universidad del País Vasco, 48080 Bilbao, Spain
^g Crop Performance and Improvement Division, Rothamsted Research, Harpenden, AL5 2JQ, United Kingdom
^h Department of Biological Sciences, Lancaster University, Lancaster, LA1 4YQ, United Kingdom
ⁱ Biodynamics Research Team, Riken Plant Science Center, Tsurumi, Yokohama 230-0045, Japan

² To whom correspondence should be addressed. E-mail hirel{at}versailles.inra.fr; fax 33-1-30-83-30-96.

The roles of two cytosolic maize glutamine synthetase isoenzymes (GS1), products of the Gln1-3 and Gln1-4 genes, were investigated by examining the impact of knockout mutations on kernel yield. In the gln1-3 and gln1-4 single mutants and the gln1-3 gln1-4 double mutant, GS mRNA expression was impaired, resulting in reduced GS1 protein and activity. The gln1-4 phenotype displayed reduced kernel size and gln1-3 reduced kernel number, with both phenotypes displayed in gln1-3 gln1-4. However, at maturity, shoot biomass production was not modified in either the single mutants or double mutants, suggesting a specific impact on grain production in both mutants. Asn increased in the leaves of the mutants during grain filling, indicating that it probably accumulates to circumvent ammonium buildup resulting from lower GS1 activity. Phloem sap analysis revealed that unlike Gln, Asn is not efficiently transported to developing kernels, apparently causing reduced kernel production. When Gln1-3 was overexpressed constitutively in leaves, kernel number increased by 30%, providing further evidence that GS1-3 plays a major role in kernel yield. Cytoimmunochemistry and in situ hybridization revealed that GS1-3 is present in mesophyll cells, whereas GS1-4 is specifically localized in the bundle sheath cells. The two GS1 isoenzymes play nonredundant roles with respect to their tissue-specific localization.

This article has been cited by other articles:

				J. R. Howarth, S. Parmar, J. Jones, C. E. Shepherd, D.-I. Corol, A. M. Galster, N. D. Hawkins, S. J. Miller, J. M. Baker, P. J. Verrier, et al. Co-ordinated expression of amino acid metabolism in response to N and S deficiency during wheat grain filling J. Exp. Bot., October 1, 2008; 59(13): 3675 - 3689. [Abstract] [Full Text] [PDF]

				M. Cossegal, P. Chambrier, S. Mbelo, S. Balzergue, M.-L. Martin-Magniette, A. Moing, C. Deborde, V. Guyon, P. Perez, and P. Rogowsky Transcriptional and Metabolic Adjustments in ADP-Glucose Pyrophosphorylase-Deficient bt2 Maize Kernels Plant Physiology, April 1, 2008; 146(4): 1553 - 1570. [Abstract] [Full Text] [PDF]

				M. Tabuchi, T. Abiko, and T. Yamaya Assimilation of ammonium ions and reutilization of nitrogen in rice (Oryza sativa L.) J. Exp. Bot., July 1, 2007; 58(9): 2319 - 2327. [Abstract] [Full Text] [PDF]

				F. M. Canovas, C. Avila, F. R. Canton, R. A. Canas, and F. de la Torre Ammonium assimilation and amino acid metabolism in conifers J. Exp. Bot., July 1, 2007; 58(9): 2307 - 2318. [Abstract] [Full Text] [PDF]

				B. Hirel, J. Le Gouis, B. Ney, and A. Gallais The challenge of improving nitrogen use efficiency in crop plants: towards a more central role for genetic variability and quantitative genetics within integrated approaches J. Exp. Bot., July 1, 2007; 58(9): 2369 - 2387. [Abstract] [Full Text] [PDF]

				B. G. Forde and P. J. Lea Glutamate in plants: metabolism, regulation, and signalling J. Exp. Bot., July 1, 2007; 58(9): 2339 - 2358. [Abstract] [Full Text] [PDF]

				J. Burstin, P. Marget, M. Huart, A. Moessner, B. Mangin, C. Duchene, B. Desprez, N. Munier-Jolain, and G. Duc Developmental Genes Have Pleiotropic Effects on Plant Morphology and Source Capacity, Eventually Impacting on Seed Protein Content and Productivity in Pea Plant Physiology, June 1, 2007; 144(2): 768 - 781. [Abstract] [Full Text] [PDF]