Constitutive overexpression of barley 4-hydroxyphenylpyruvate dioxygenase in tobacco results in elevation of the vitamin E content in seeds but not in leaves

With the aim to enhance the plant vitamin E content, the barley gene encoding 4-hydroxyphenylpyruvate dioxygenase was overexpressed in tobacco plants under control of the 35S promoter. Transgenic lines have a higher capacity for homogentisate biosynthesis as evident by a more than 10-fold higher resistance towards the bleaching herbicide sulcotrione. Seeds from transgenic lines have an up to two-fold enhanced level of vitamin E without a change in the ratio of gamma-tocopherol and gamma-tocotrienol. While the vitamin E content is not affected in leaves, the level of plastoquinone is enhanced in leaves of transgenic lines during leaf senescence. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.