Chrysanthemums may appear fairly uninteresting compared to the many exotics of the plant world, but recent research proves they really are fascinating. As the world’s most important ornamental flower, it is thought that today’s modern varieties originated from white and yellow flowered plants. Crosses showed that white petal colour is dominant over yellow and it was originally thought that a single dominant gene inhibited carotenoid accumulation.
Recent research by Akemi Ohmiya et al. at the National Institute of Floricultural Sciences, Japan, has found that carotenoids are actually synthesised in white chrysanths although they are subsequently degraded into colourless compounds, resulting in white flower colour. The degradation is thought to be due to high expression of the CmCCD4a transcript found in white flowers, which is highly homologous to a carotenoid cleavage dioxygenase.
The paper Carotenoid cleavage dioxygenase (CmCCD4a) contributes to white colour fomration in chrysanthemum petals has been published in Plant Physiology 142:1193-1201.