TitleAlteration of flower color in Solanum lycopersicum through ectopic expression of a gene for capsanthin-capsorubin synthase from Lilium lancifolium
Publication TypeThesis
Year of Publication2015
AuthorsJeknic, S
UniversityOregon State University
CityCorvallis, Or.
Thesis TypeHonors College Thesis

Tomato flowers (Solanum lycopersicum) were used as a model system to investigate flower color modification by alteration of the carotenoid biosynthetic pathway, due to their ease of transformation and short time from seed to flowering. Tomato flowers are naturally bright yellow, primarily due to the accumulation of violaxanthin. Violaxanthin is a precursor of capsanthin-capsorubin synthase (ccs), which catalyzes the conversion of antheraxanthin and violaxanthin, two yellow xanthophylls, into capsanthin and capsorubin, two red κ-xanthophylls, respectively. A capsanthin-capsorubin synthase gene cloned from tiger lily (Lilium lancifolium) was expressed in tomatoes under the control of the promoter from a petunia chalcone synthase gene, fused to an enhancer sequence of the cauliflower mosaic virus 35S promoter. All transgenic lines produced flowers with a light orange pigmentation, as opposed to the natural yellow coloration. UHPLC analysis confirmed that the color change coincided with the accumulation of two novel carotenoids, capsanthin and a capsanthin-like carotenoid. A more pronounced color change likely could have been achieved using a stronger promoter or by down-regulating competing pathways. Nevertheless, these results indicate that alteration of the carotenoid biosynthetic pathway with a gene for capsanthin-capsorubin synthase is a possible strategy for producing novel red and orange hues in certain ornamental crops.