Light-dependent switch from formation of poly-cis carotenes to all-trans carotenoids in the Scenedesmus mutant C-6D
- Cite this article as:
- Sandmann, G. Arch. Microbiol. (1991) 155: 229. doi:10.1007/BF00252205
- 81 Downloads
The Scenedesmus obliquus mutant C-6D forms untypical poly-cis carotenes and lacks cyclic carotenoids when grown heterotrophically in the dark. After transfer to light, a very fast formation of usual all-trans carotenoids is observed leading to a phenotype very similar to the wild-type. Carotene analysis and quantitative kinetics of carotenoid changes after illumination in the presence of inhibitors which inhibit the three enzymes involved in carotene conversion showed isomerization of poly-cis carotenes, especially pro-ξ-carotene, to all-trans isomers. This result and consequently photoisomerization of pro-ξ-carotene in solution demonstrated that photoisomerization is the light-dependent mechanism leading to all-trans carotenoids in illuminated cultures. Now the different phenotypes of Scenedesmus C-6D can be explained by a single mutation of phytoene desaturase when photoisomerization of poly-cis carotenes is considered.
Key wordsAcyclic poly-cis carotenes Carotene biosynthesis Light-dependent xanthophyll formation Photoisomerization Pigment mutant C-6D of Scenedesmus obliquus