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ARS Home » Research » Publications at this Location » Publication #113896
Title: OVER-EXPRESSION OF CYTOSOLIC GLUTAMINE SYNTHETASE INCREASES PHOTOSYNTHESIS AND GROWTH AT LOW NITROGEN CONCENTRATIONS

Author
item FUENTES, SARA - AVENIDA UNIVERSIDA MEXICO
item ALLEN, DAMIAN
item Ortiz Lopez, Adriana
item HERNANDEZ, GEORGINA - AVENIDA UNIVERSIDA MEXICO

Submitted to: Plant Physiology Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 7/19/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Increasing global nitrogen pollution from agricultural fertilizer is one of the major threats to human health and the environment. Manipulation of crop nitrogen metabolism could help alleviate this threat by reducing nitrogen use while maintaining productivity. Glutamine synthetase (GS) catalyzes the critical incorporation of inorganic ammonium into the amino acid glutamine. Tobacco (Nicotiana tabacum) plants overexpressing cytosolic GS, driven by the constitutive CaMV 35S promoter, had a 5-7 fold higher leaf GS activity than controls. There was no effect of GS over-expression on photosynthesis or growth under optimum nitrogen fertilization conditions. However, under nitrogen starvation the GS transgenics grew ca. 70 percent larger 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 percent by nitrogen deprivation. Therefore we demonstrate that manipulation of GS activity has the potential to maintain crop photosynthetic productivity while reducing nitrogen fertilization and the concomitant pollution.