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Three cytosolic glutamine synthetase isoforms localized in different-order veins act together for N remobilization and seed filling in Arabidopsis
Glutamine synthetase (GS) is central for ammonium assimilation and consists of cytosolic (GS1) and chloroplastic (GS2) isoenzymes. During plant ageing, GS2 protein decreases due to chloroplast degradation, and GS1 activity increases to support glutamine biosynthesis and N remobilization from senesci...
Autores principales: | , , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6093384/ https://www.ncbi.nlm.nih.gov/pubmed/29873769 http://dx.doi.org/10.1093/jxb/ery217 |
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author | Moison, Michael Marmagne, Anne Dinant, Sylvie Soulay, Fabienne Azzopardi, Marianne Lothier, Jérémy Citerne, Sylvie Morin, Halima Legay, Nicolas Chardon, Fabien Avice, Jean-Christophe Reisdorf-Cren, Michèle Masclaux-Daubresse, Céline |
author_facet | Moison, Michael Marmagne, Anne Dinant, Sylvie Soulay, Fabienne Azzopardi, Marianne Lothier, Jérémy Citerne, Sylvie Morin, Halima Legay, Nicolas Chardon, Fabien Avice, Jean-Christophe Reisdorf-Cren, Michèle Masclaux-Daubresse, Céline |
author_sort | Moison, Michael |
collection | PubMed |
description | Glutamine synthetase (GS) is central for ammonium assimilation and consists of cytosolic (GS1) and chloroplastic (GS2) isoenzymes. During plant ageing, GS2 protein decreases due to chloroplast degradation, and GS1 activity increases to support glutamine biosynthesis and N remobilization from senescing leaves. The role of the different Arabidopsis GS1 isoforms in nitrogen remobilization was examined using (15)N tracing experiments. Only the gln1;1-gln1;2-gln1;3 triple-mutation affecting the three GLN1;1, GLN1;2, and GLN1;3 genes significantly reduced N remobilization, total seed yield, individual seed weight, harvest index, and vegetative biomass. The triple-mutant accumulated a large amount of ammonium that could not be assimilated by GS1. Alternative ammonium assimilation through asparagine biosynthesis was increased and was related to higher ASN2 asparagine synthetase transcript levels. The GS2 transcript, protein, and activity levels were also increased to compensate for the lack of GS1-related glutamine biosynthesis. Localization of the different GLN1 genes showed that they were all expressed in the phloem companion cells but in veins of different order. Our results demonstrate that glutamine biosynthesis for N-remobilization occurs in veins of all orders (major and minor) in leaves, it is mainly catalysed by the three major GS1 isoforms (GLN1;1, GLN1;2, and GLN1;3), and it is alternatively supported by AS2 in the veins and GS2 in the mesophyll cells. |
format | Online Article Text |
id | pubmed-6093384 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-60933842018-08-22 Three cytosolic glutamine synthetase isoforms localized in different-order veins act together for N remobilization and seed filling in Arabidopsis Moison, Michael Marmagne, Anne Dinant, Sylvie Soulay, Fabienne Azzopardi, Marianne Lothier, Jérémy Citerne, Sylvie Morin, Halima Legay, Nicolas Chardon, Fabien Avice, Jean-Christophe Reisdorf-Cren, Michèle Masclaux-Daubresse, Céline J Exp Bot Research Papers Glutamine synthetase (GS) is central for ammonium assimilation and consists of cytosolic (GS1) and chloroplastic (GS2) isoenzymes. During plant ageing, GS2 protein decreases due to chloroplast degradation, and GS1 activity increases to support glutamine biosynthesis and N remobilization from senescing leaves. The role of the different Arabidopsis GS1 isoforms in nitrogen remobilization was examined using (15)N tracing experiments. Only the gln1;1-gln1;2-gln1;3 triple-mutation affecting the three GLN1;1, GLN1;2, and GLN1;3 genes significantly reduced N remobilization, total seed yield, individual seed weight, harvest index, and vegetative biomass. The triple-mutant accumulated a large amount of ammonium that could not be assimilated by GS1. Alternative ammonium assimilation through asparagine biosynthesis was increased and was related to higher ASN2 asparagine synthetase transcript levels. The GS2 transcript, protein, and activity levels were also increased to compensate for the lack of GS1-related glutamine biosynthesis. Localization of the different GLN1 genes showed that they were all expressed in the phloem companion cells but in veins of different order. Our results demonstrate that glutamine biosynthesis for N-remobilization occurs in veins of all orders (major and minor) in leaves, it is mainly catalysed by the three major GS1 isoforms (GLN1;1, GLN1;2, and GLN1;3), and it is alternatively supported by AS2 in the veins and GS2 in the mesophyll cells. Oxford University Press 2018-08-17 2018-06-05 /pmc/articles/PMC6093384/ /pubmed/29873769 http://dx.doi.org/10.1093/jxb/ery217 Text en © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. http://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Papers Moison, Michael Marmagne, Anne Dinant, Sylvie Soulay, Fabienne Azzopardi, Marianne Lothier, Jérémy Citerne, Sylvie Morin, Halima Legay, Nicolas Chardon, Fabien Avice, Jean-Christophe Reisdorf-Cren, Michèle Masclaux-Daubresse, Céline Three cytosolic glutamine synthetase isoforms localized in different-order veins act together for N remobilization and seed filling in Arabidopsis |
title | Three cytosolic glutamine synthetase isoforms localized in different-order veins act together for N remobilization and seed filling in Arabidopsis |
title_full | Three cytosolic glutamine synthetase isoforms localized in different-order veins act together for N remobilization and seed filling in Arabidopsis |
title_fullStr | Three cytosolic glutamine synthetase isoforms localized in different-order veins act together for N remobilization and seed filling in Arabidopsis |
title_full_unstemmed | Three cytosolic glutamine synthetase isoforms localized in different-order veins act together for N remobilization and seed filling in Arabidopsis |
title_short | Three cytosolic glutamine synthetase isoforms localized in different-order veins act together for N remobilization and seed filling in Arabidopsis |
title_sort | three cytosolic glutamine synthetase isoforms localized in different-order veins act together for n remobilization and seed filling in arabidopsis |
topic | Research Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6093384/ https://www.ncbi.nlm.nih.gov/pubmed/29873769 http://dx.doi.org/10.1093/jxb/ery217 |
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