A method for obtaining a transgenic plant that over-expresses a soluble isoform AGPPase enzyme. The method includes a step of transforming a plant with a vector comprising a polynucleotide of SEQ ID NO: 7 linked to a promoter that promotes expression of the polynucleotide in the plant whereby to form the transgenic plant. The transgenic plant has a reduced starch content and a higher resistance to salinity than the plant before the transforming step.