title: Ketocarotenoid formation in transgenic potato.
abstract: Potato has been genetically engineered for the production of commercially important ketocarotenoids including astaxanthin (3,3'-dihydroxy 4,4'-diketo-beta-carotene). To support the formation of 3-hydroxylated and 4-ketolated beta-carotene, a transgenic potato line accumulating zeaxanthin due to inactivated zeaxanthin epoxidase was co-transformed with the crtO beta-carotene ketolase gene from the cyanobacterium Synechocystis under a constitutive promoter. Plants were generated which exhibited expression of this gene, resulting in an accumulation of echinenone, 3'-hydroxyechinenone, and 4-ketozeaxanthin in leaves, as well as 3'-hydroxyechinenone, 4-ketozeaxanthin together with astaxanthin in the tuber. The amount of ketocarotenoids formed represent approximately 10-12% of total carotenoids in leaves and tubers. Negative effects on photosynthesis due to the presence of the ketocarotenoids in leaves could be excluded by the determination of variable fluorescence.
authors.affiliation: Molecular Biosciences 213, J.W. Goethe Universität, PO Box 111932, D-60054 Frankfurt/M., Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Gerjets
authors.forename: Gerhard
authors.initials: G
authors.lastname: Sandmann
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D002338:Carotenoids / Q000096:biosynthesis* / Q000737:chemistry; D010105:Oxygenases / Q000235:genetics; D010788:Photosynthesis / Q000235:genetics; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D035281:Plant Tubers / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism*; D011198:Solanum tuberosum / Q000235:genetics*; D046939:Synechocystis / Q000235:genetics; D014170:Transformation, Genetic; D024341:Xanthophylls / Q000235:genetics / Q000378:metabolism; D065146:Zeaxanthins
chemical_list: D001426:Bacterial Proteins; D024341:Xanthophylls; D065146:Zeaxanthins; D002338:Carotenoids; D010105:Oxygenases; C093259:beta-carotene ketolase