The invention relates to methods for the transgenic expression of nucleic acid sequences predominantly in starch-comprising tissues of plants, preferably in fruits, roots, seeds or tubers, wherein the nucleic acid sequence is expressed under the control of a promoter of a starch synthase 3. Furthermore in accordance with the invention are transgenic expression cassettes and vectors comprising a promoter of a starch synthase 3, and the use thereof for the production of foodstuffs, feedstuffs, seed, pharmaceuticals or fine chemicals.