Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Gene expression, cellular localisation and function of glutamine synthetase isozymes in wheat (Triticum aestivum L.)
AU - Bernard, Stéphanie M
AU - Møller, Anders Laurell Blom
AU - Dionisio, Giuseppe
AU - Kichey, Thomas
AU - Jahn, Thomas P
AU - Dubois, Frederic
AU - Baudo, Marcela
AU - Lopes, Marta S
AU - Tercé-Laforgue, Thérèse
AU - Foyer, Christine H
AU - Parry, Martin A J
AU - Forde, Brian G
AU - Araus, Jose Luis
AU - Hirel, Bertrand
AU - Schjoerring, Jan K
AU - Habash, Dimah Z
PY - 2008
Y1 - 2008
N2 - We present the first cloning and study of glutamine synthetase (GS) genes in wheat (Triticum aestivum L.). Based on sequence analysis, phylogenetic studies and mapping data, ten GS sequences were classified into four sub-families: GS2 (a, b and c), GS1 (a, b and c), GSr (1 and 2) and GSe (1 and 2). Phylogenetic analysis showed that the wheat GS sub-families together with the GS genes from other monocotyledonous species form four distinct clades. Immunolocalisation studies in leaves, stems and rachis in plants at flowering showed GS protein to be present in parenchyma, phloem companion and perifascicular sheath cells. In situ localisation confirmed that GS1 transcripts were present in the perifascicular sheath cells whilst those for GSr were confined to the vascular cells. Studies of the expression and protein profiles showed that all GS sub-families were differentially expressed in the leaves, peduncle, glumes and roots. Expression of GS genes in leaves was developmentally regulated, with both GS2 and GS1 assimilating or recycling ammonia in leaves during the period of grain development and filling. During leaf senescence the cytosolic isozymes, GS1 and GSr, were the predominant forms, suggesting major roles in assimilating ammonia during the critical phases of remobilisation of nitrogen to the grain. A preliminary analysis of three different wheat genotypes showed that the ratio of leaf GS2 protein to GS1 protein was variable. Use of this genetic variation should inform future efforts to modulate this enzyme for pre-breeding efforts to improve nitrogen use in wheat.
AB - We present the first cloning and study of glutamine synthetase (GS) genes in wheat (Triticum aestivum L.). Based on sequence analysis, phylogenetic studies and mapping data, ten GS sequences were classified into four sub-families: GS2 (a, b and c), GS1 (a, b and c), GSr (1 and 2) and GSe (1 and 2). Phylogenetic analysis showed that the wheat GS sub-families together with the GS genes from other monocotyledonous species form four distinct clades. Immunolocalisation studies in leaves, stems and rachis in plants at flowering showed GS protein to be present in parenchyma, phloem companion and perifascicular sheath cells. In situ localisation confirmed that GS1 transcripts were present in the perifascicular sheath cells whilst those for GSr were confined to the vascular cells. Studies of the expression and protein profiles showed that all GS sub-families were differentially expressed in the leaves, peduncle, glumes and roots. Expression of GS genes in leaves was developmentally regulated, with both GS2 and GS1 assimilating or recycling ammonia in leaves during the period of grain development and filling. During leaf senescence the cytosolic isozymes, GS1 and GSr, were the predominant forms, suggesting major roles in assimilating ammonia during the critical phases of remobilisation of nitrogen to the grain. A preliminary analysis of three different wheat genotypes showed that the ratio of leaf GS2 protein to GS1 protein was variable. Use of this genetic variation should inform future efforts to modulate this enzyme for pre-breeding efforts to improve nitrogen use in wheat.
KW - Glutamine synthetase
KW - Wheat
KW - Senescence
KW - Nitrogen
KW - Gene expression
KW - In situ hybridisation
KW - Immunolocalisation
UR - http://www.scopus.com/inward/record.url?scp=42149149802&partnerID=8YFLogxK
U2 - 10.1007/s11103-008-9303-y
DO - 10.1007/s11103-008-9303-y
M3 - Journal article
C2 - 18288574
VL - 67
SP - 89
EP - 105
JO - Plant Molecular Biology
JF - Plant Molecular Biology
SN - 0167-4412
IS - 1-2
ER -