scholarly journals Cytosolic Glutamine Synthetase Gln1;2 Is the Main Isozyme Contributing to GS1 Activity and Can Be Up-Regulated to Relieve Ammonium Toxicity

2016 ◽  
Vol 171 (3) ◽  
pp. 1921-1933 ◽  
Author(s):  
Miao Guan ◽  
Thomas C. de Bang ◽  
Carsten Pedersen ◽  
Jan K. Schjoerring
Keyword(s):  
Glutamine Synthetase ◽  
Ammonium Toxicity ◽  
Cytosolic Glutamine Synthetase

scholarly journals How do three cytosolic glutamine synthetase isozymes of wheat perform N assimilation and translocation?

2019 ◽  
Author(s):  
Yihao Wei ◽  
Xiaochun Wang ◽  
Zhiyong Zhang ◽  
Shuping Xiong ◽  
Yiming Zhang ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Assimilation ◽  
Root Tip ◽  
Kinetic Properties ◽  
Meristematic Zone ◽  
Ammonium Toxicity ◽  
Vascular Tissues ◽  
High Affinity ◽  
N Assimilation ◽  
Cytosolic Glutamine Synthetase

AbstractTo understand how the three cytosolic glutamine synthetase (GS1) isozymes of wheat (Triticum aestivum L., TaGS1) perform nitrogen assimilation and translocation, we studied the kinetic properties of TaGS1 isozymes, the effects of nitrogen on the expression and localization of TaGS1 isozymes with specific antibodies, and the nitrogen metabolism. The results showed TaGS1;1, the dominant TaGS1 isozyme, had a high affinity for substrates, and was widely localized in the mesophyll cells, root pericycle and root tip meristematic zone, suggesting it was the primary isozyme for N assimilation. TaGS1;2, with a high affinity for Glu, was activated by Gln, and was mainly localized in the around vascular tissues, indicating that TaGS1;2 catalyzed Gln synthesis in low Glu concentration, then the Gln returned to activate TaGS1;2, which may lead to the rapid accumulation of Gln around the vascular tissues. TaGS1;3 had low affinity for substrates but the highest Vmax among TaGS1, was mainly localized in the root tip meristematic zone; exogenous NH4+ could promote TaGS1;3 expressing, indicating that TaGS1;3 could rapidly assimilate NH4+ to relieve NH4+ toxicity. In conclusion, TaGS1;1, TaGS1;2 and TaGS1;3 have different role in N assimilation, Gln translocation and relieving ammonium toxicity, respectively, and synergistically perform nitrogen assimilation and translocation.HighlightThree cytosolic glutamine synthase isozymes of wheat have different role and synergistically perform nitrogen assimilation and translocation.

scholarly journals Biochemical Background and Compartmentalized Functions of Cytosolic Glutamine Synthetase for Active Ammonium Assimilation in Rice Roots

2004 ◽  
Vol 45 (11) ◽  
pp. 1640-1647 ◽  
Author(s):  
Keiki Ishiyama ◽  
Eri Inoue ◽  
Mayumi Tabuchi ◽  
Tomoyuki Yamaya ◽  
Hideki Takahashi
Keyword(s):  
Glutamine Synthetase ◽  
Ammonium Assimilation ◽  
Rice Roots ◽  
Cytosolic Glutamine Synthetase
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