A method for the preparation of a eukaryotic organism, for example selected from plants, animals and fungi, showing constitutive, inducible and/or organ specific expression of a specifically modified TPS gene, which comprises the steps of providing a TPS gene; designing a suitable modification to the TPS gene by aligning the gene with the corresponding gene of yeast and establishing which part of the gene extends beyond the 5′ terminus of the yeast gene; deleting or inactivating a part of the N-terminal region of the TPS gene extending beyond the 5′ terminus of the yeast gene, in order to achieve an increased trehalose-6-phosphate synthase activity; cloning the thus modified gene into an expression vector under the control of a constitutive, inducible and/or organ-specific promoter; transforming a plant cell or tissue with the thus obtained expression vector; and regenerating a complete plant from the transformed plant cell or tissue.