Influences on tocopherol biosynthesis in the cyanobacterium Synechocystis sp PCC 6803

To elucidate influences on the tocopherol biosynthesis in cyanobacteria, wild type and mutant cells of a putative methyltransferase in tocopherol and plastoquinone biosynthesis of Synechocystis sp. PCC 6803 were grown under different conditions. The vitamin E content of cells grown under different tight regimes, photomixotrophic or photoautotrophic conditions and varying carbon dioxide supplies were compared by HPLC measurements. The tocopherol levels in wild type cells increased under higher tight conditions and tow carbon dioxide supply. Photomixotrophic growth led to tower vitamin E amounts in the cells compared to those grown photoautotrophically. We were able to segregate a homozygous Delta sll0418 mutant under photoautotrophic conditions. In contrast to former suggestions in the literature the deletion of this gene is not lethal under photomixotrophic conditions and the influence on tocopherol and plastoquinone amounts is diminutive. The methyltransferase encoded by the gene sll0418 is not essential either for tocopherol or plastoquinone synthesis. (c) 2005 Elsevier GmbH. All rights reserved.