"Yellow Jimba": Suppression of carotenoid cleavage dioxygenase (CmCCD4a) expression turns white chrysanthemum petals yellow

Abstract

'Jimba' is the most popular white-flowered chrysanthemum cultivar in Japan. A yellow-flowered cultivar with the same growth properties as 'Jimba' will benefit growers because both forms could be produced under the same conditions. Many breeders have therefore tried to produce a "Yellow Jimba" by mutation breeding but have not yet succeeded. Previously, we showed that color mutation from white to yellow in the petals of ray florets is caused by the loss of a carotenoid cleavage dioxygenase gene, CmCCD4a. Here we introduced two separate CmCCD4a RNAi constructs into 'Jimba' by Agrobacterium-medtated transformation. The double-transformation effectively suppressed CmCCD4a expression in petals, which became yellow. The yellowest transformants contained 102 μg·g-1 FW carotenoids in the petals, and the expression level of CmCCD4a was 0.4% of the wildtype level. Although the transformed plants were significantly smaller than the wild type, flower size was unchanged. We consider that CmCCD4a could become a powerful tool for petal color manipulation from white to yellow. JSHS © 2009.