Increased nutritive value of transgenic potato by expressing a nonallergenic seed albumin gene from Amaranthus hypochondriacus

Improvement of nutritive value of crop plants, in particular the amino acid composition, has been a major long-term goal of plant breeding programs. T oward this end, we reported earlier the cloning of the seed albumin gene Am A1 from Amaranthus hypochondriacus, The AmA1 protein is nonallergenic in na ture and is rich in ail essential amino acids, and the composition correspo nds well with the World Health Organization standards for optimal human nut rition. In an attempt to improve the nutritional value of potato, the AmA1 coding sequence was successfully introduced and expressed in tuber-specific and constitutive manner. There was a striking increase in the growth and p roduction of tubers in transgenic populations and also of the total protein content with an increase in most essential amino acids. The expressed prot ein was localized in the cytoplasm as well as in the vacuole of transgenic tubers. Thus we have been able to use a seed albumin gene with a well-balan ced amino acid composition as a donor protein to develop a transgenic crop plant. The results document, in addition to successful nutritional improvem ent of potato tubers, the feasibility of genetically modifying other crop p lants with novel seed protein composition.