The disruption of the Synechocystis open reading frame Deltaslr0090 encoding a gene with high homology to plant genes encoding 4-hydroxyphenylpyruvate dioxygenase results in an impairment of tocopherol biosynthesis without affecting levels of plastoquinone, carotenoids and chlorophyll as well as cell growth and photosynthesis. Our results indicate that in Synechocystis in contrast to the situation in higher plants the 4-hydroxyphenylpyruvate dioxygenase is not required for the synthesis of plastoquinone.