Ketocarotenoid formation in transgenic potato

• Published in: Journal of experimental botany 2006-11, Vol.57 (14), p.3639-3645
• Main Authors: Gerjets, Tanja, Sandmann, Gerhard
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Astaxanthin; Bacterial Proteins - genetics; beta-carotene; beta-carotene ketolase; Biological and medical sciences; Biosynthesis; Carotenoids; Carotenoids - biosynthesis; Carotenoids - chemistry; chemical constituents of plants; Cyanophyta; DNA; enzymes; Fundamental and applied biological sciences. Psychology; gene expression; genes; genetic transformation; Genetics and breeding of economic plants; ketocarotenoids; ketolase gene crtO; Leaves; Metabolism; molecular sequence data; oxidoreductases; Oxygenases - genetics; Pest resistance; photosynthesis; Photosynthesis - genetics; Plant Leaves - genetics; Plant Leaves - metabolism; Plant pathogens; Plant Tubers - genetics; Plant Tubers - metabolism; Plants; Plants, Genetically Modified - metabolism; Plasmids; potatoes; promoter regions; Research Papers; RNA; Solanum tuberosum; Solanum tuberosum - genetics; Synechocystis; Synechocystis - genetics; Transformation, Genetic; Transgenic plants; transgenic potato; tuber carotenoids; Tubers; Varietal selection. Specialized plant breeding, plant breeding aims; Xanthophylls - genetics; Xanthophylls - metabolism; zeaxanthin; zeaxanthin epoxidase; Zeaxanthins
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erl103

Potato has been genetically engineered for the production of commercially important ketocarotenoids including astaxanthin (3,3′-dihydroxy 4,4′-diketo-β-carotene). To support the formation of 3-hydroxylated and 4-ketolated β-carotene, a transgenic potato line accumulating zeaxanthin due to inactivated zeaxanthin epoxidase was co-transformed with the crtO β-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 ∼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.