Over-expression of cytosolic glutamine synthetase increases photosynthesis and growth at low nitrogen concentrations
Nitrogen, which is a major limiting nutrient for plant growth, is assimilated as ammonium by the concerted action of glutamine synthetase (GS) and glutamate synthase (GOGAT). GS catalyses the critical incorporation of inorganic ammonium into the amino acid glutamine. Two types of GS isozymes, locate...
| Veröffentlicht in: | Journal of experimental botany. - 1985. - 52(2001), 358 vom: 31. Mai, Seite 1071-81 |
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| Weitere Verfasser: | , , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2001
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| Zugriff auf das übergeordnete Werk: | Journal of experimental botany |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Glutamate-Ammonia Ligase EC 6.3.1.2 Nitrogen N762921K75 |
| Zusammenfassung: | Nitrogen, which is a major limiting nutrient for plant growth, is assimilated as ammonium by the concerted action of glutamine synthetase (GS) and glutamate synthase (GOGAT). GS catalyses the critical incorporation of inorganic ammonium into the amino acid glutamine. Two types of GS isozymes, located in the cytosol (GS1) and in the chloroplast (GS2) have been identified in plants. Tobacco (Nicotiana tabacum) transformants, over-expressing GS1 driven by the constitutive CaMV 35S promoter were analysed. GS in leaves of GS-5 and GS-8 plants was up-regulated, at the level of RNA and proteins. These transgenic plants had six times higher leaf GS activity than controls. Under optimum nitrogen fertilization conditions there was no effect of GS over-expression on photosynthesis or growth. However, under nitrogen starvation the GS transgenics had c. 70% higher shoot and c. 100% greater root dry weight as well as 50% more leaf area than low nitrogen controls. This was achieved by the maintenance of photosynthesis at rates indistinguishable from plants under high nitrogen, while photosynthesis in control plants was inhibited by 40-50% by nitrogen deprivation. It was demonstrated that manipulation of GS activity has the potential to maintain crop photosynthetic productivity while reducing nitrogen fertilization and the concomitant pollution |
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| Beschreibung: | Date Completed 30.08.2001 Date Revised 13.12.2023 published: Print Citation Status MEDLINE |
| ISSN: | 1460-2431 |