Cytosolic glutamine synthetase Gln1;2 is the main isozyme contributing to GS1 activity and can be up-regulated to relieve ammonium toxicity
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Cytosolic glutamine synthetase Gln1;2 is the main isozyme contributing to GS1 activity and can be up-regulated to relieve ammonium toxicity. / Guan, Miao; de Bang, Thomas Christian; Pedersen, Carsten; Schjørring, Jan Kofod.
In: Plant Physiology, Vol. 171, No. 3, 2016, p. 1921-1933.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Cytosolic glutamine synthetase Gln1;2 is the main isozyme contributing to GS1 activity and can be up-regulated to relieve ammonium toxicity
AU - Guan, Miao
AU - de Bang, Thomas Christian
AU - Pedersen, Carsten
AU - Schjørring, Jan Kofod
N1 - © 2016 American Society of Plant Biologists. All Rights Reserved.
PY - 2016
Y1 - 2016
N2 - Cytosolic GS1 (Gln synthetase) is central for ammonium assimilation in plants. High ammonium treatment enhanced the expression of the GS1 isogene Gln-1;2 encoding a low-affinity high-capacity GS1 protein in Arabidopsis (Arabidopsis thaliana) shoots. Under the same conditions, the expression of the high-affinity low-capacity isoform Gln-1;1 was reduced. The expression of Gln-1;3 did not respond to ammonium treatment while Gln-1;4 and Gln-1;5 isogenes in all cases were expressed at a very low level. Gln-2 was highly expressed in shoots but only at a very low level in roots. To investigate the specific functions of the two isogenes Gln-1;1 and Gln-1;2 in shoots for ammonium detoxification, single and double knock-out mutants were grown under standard N supply or with high ammonium provision. Phenotypes of the single mutant gln1;1 were similar to the wild type, while growth of the gln1;2 single mutant and the gln1;1:gln1;2 double mutant was significantly impaired irrespective of N regime. GS1 activity was significantly reduced in both gln1;2 and gln1;1:gln1;2 Along with this, the ammonium content increased while that of Gln decreased, showing that Gln-1;2 was essential for ammonium assimilation and amino acid synthesis. We conclude that Gln-1;2 is the main isozyme contributing to shoot GS1 activity in vegetative growth stages and can be up-regulated to relieve ammonium toxicity. This reveals, to our knowledge, a novel shoot function of Gln-1;2 in Arabidopsis shoots.
AB - Cytosolic GS1 (Gln synthetase) is central for ammonium assimilation in plants. High ammonium treatment enhanced the expression of the GS1 isogene Gln-1;2 encoding a low-affinity high-capacity GS1 protein in Arabidopsis (Arabidopsis thaliana) shoots. Under the same conditions, the expression of the high-affinity low-capacity isoform Gln-1;1 was reduced. The expression of Gln-1;3 did not respond to ammonium treatment while Gln-1;4 and Gln-1;5 isogenes in all cases were expressed at a very low level. Gln-2 was highly expressed in shoots but only at a very low level in roots. To investigate the specific functions of the two isogenes Gln-1;1 and Gln-1;2 in shoots for ammonium detoxification, single and double knock-out mutants were grown under standard N supply or with high ammonium provision. Phenotypes of the single mutant gln1;1 were similar to the wild type, while growth of the gln1;2 single mutant and the gln1;1:gln1;2 double mutant was significantly impaired irrespective of N regime. GS1 activity was significantly reduced in both gln1;2 and gln1;1:gln1;2 Along with this, the ammonium content increased while that of Gln decreased, showing that Gln-1;2 was essential for ammonium assimilation and amino acid synthesis. We conclude that Gln-1;2 is the main isozyme contributing to shoot GS1 activity in vegetative growth stages and can be up-regulated to relieve ammonium toxicity. This reveals, to our knowledge, a novel shoot function of Gln-1;2 in Arabidopsis shoots.
KW - Journal Article
U2 - 10.1104/pp.16.01195
DO - 10.1104/pp.16.01195
M3 - Journal article
C2 - 27231101
VL - 171
SP - 1921
EP - 1933
JO - Plant Physiology
JF - Plant Physiology
SN - 0032-0889
IS - 3
ER -
ID: 169134237