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Analysis of glutamate homeostasis by overexpression of Fd-GOGAT gene in Arabidopsis thaliana.
- Source :
-
Amino acids [Amino Acids] 2010 Mar; Vol. 38 (3), pp. 943-50. Date of Electronic Publication: 2009 May 26. - Publication Year :
- 2010
-
Abstract
- Glutamate plays a central role in nitrogen flow and serves as a nitrogen donor for the production of amino acids. In plants, some amino acids work as buffers: during photorespiration, ammonium derived from the conversion of glycine to serine is promptly reassimilated into glutamate by the glutamine synthetase (GS-2)/ferredoxin-dependent glutamate synthase (Fd-GOGAT) cycle. The glutamate concentration is relatively stable compared with those of other amino acids under environmental changes. The few studies dealing with glutamate homeostasis have but all used knockouts or mutants of these enzymes. Here, we generated Fd-GOGAT (GLU1)-overexpressing Arabidopsis plants to analyze changes in the amino acid pool caused by glutamate overproduction under different ammonium conditions controlled by CO(2) concentration, light intensity and nitrate concentration. Under photorespiratory conditions with sufficient ammonium supply, aspartate increased and glutamine and glycine decreased, but glutamate barely changed. Under non-photorespiratory conditions, however, glutamate and most other amino acids increased. These results suggest that the synthesized glutamate is promptly converted into other amino acids, especially aspartate. In addition, ammonium supply by photorespiration does not limit glutamate biosynthesis, but glutamine and glycine are important. This study will contribute to the understanding of glutamate homeostasis in plants.
- Subjects :
- Amino Acid Oxidoreductases biosynthesis
Amino Acid Oxidoreductases metabolism
Amino Acids metabolism
Arabidopsis genetics
Arabidopsis radiation effects
Arabidopsis Proteins biosynthesis
Arabidopsis Proteins metabolism
Carbon metabolism
Carbon Dioxide administration & dosage
Cell Respiration genetics
Light
Nitrates administration & dosage
Nitrogen metabolism
Plant Components, Aerial genetics
Plant Components, Aerial metabolism
Plant Components, Aerial radiation effects
Plant Leaves genetics
Plant Leaves metabolism
Plant Leaves radiation effects
Plants, Genetically Modified
RNA, Messenger metabolism
Reverse Transcriptase Polymerase Chain Reaction
Seedlings genetics
Seedlings metabolism
Seedlings radiation effects
Amino Acid Oxidoreductases genetics
Arabidopsis metabolism
Arabidopsis Proteins genetics
Gene Expression
Glutamic Acid metabolism
Homeostasis radiation effects
Subjects
Details
- Language :
- English
- ISSN :
- 1438-2199
- Volume :
- 38
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Amino acids
- Publication Type :
- Academic Journal
- Accession number :
- 19468822
- Full Text :
- https://doi.org/10.1007/s00726-009-0303-2