The invention relates to a method for expressing a desired protein or polypeptide in a plant, in which the protein or polypeptide is expressed as a fusion with at least one starch binding domain. The plant is preferably a plant that contains or produces starch or starch granules in at least one of its parts, such as potato, sweet potato, cassava, pea, taro, sago, yam, banana and/or cereals such as rice, maize, wheat and barley. The protein or polypeptide can be an enzyme, in particular an enzyme that can convert, modify, alter, degrade or otherwise influence starch (granules); or can be a receptor or a structural protein. The invention further relates to the fusions thus obtained, to genetic constructs that encode the above fusions and to plants transformed with said constructs. The method of the invention can in particular be used to provide modified starches and/or to provide complexes of starch (granules) and the above fusions. In another embodiment, one or more starch binding domains are expressed in a plant, to provide a plant producing modified starches.