Oranje Boven (Orange on top) Is there mutual exclusion between anthocyanins and carotenoids in petunia flowers?

The goal of the ‘Orange on Top’ project was to find out more about carotenoid biosynthesis in flowers of ornamental plants, specifically in petunia. In nature, petunia is white, or colored pink, red, and purple by anthocyanin pigments, and no species exist with carotenoids in the flowers. However, yellow colors are popular, and commercial hybrids exists with yellow carotenoids in the flower. The composition of yellow in was always very similar in composition, and only varied by concentration and patterns. It turned out to be dependent on the presence of a new transcriptional regulator, which we further characterized.