Cloning of GS1 gene encodes glutamine synthetase 1 and construction of transformation vector

Glutamine synthetase (EC 6.3.1.2) is an enzyme which assimilates ammonium into amino acids. Therefore, GS plays an essential role in the metabolism of nitrogen. In vascular plants, GS is devided into two groups: cytosol - located isoform (GS1) and plastid – located isoform (GS2). Surveys have shown that GS1 gene was used widely to generate transgenic plants. Effects on the growth characteristics of GS1 transgenic plants have been reported in many researches.