Identification and Characterization of Petal Color Change from Pink to Yellow in Chrysanthemum morifolium ‘Pink Candy’ and Its Bud Variant

Abstract

Chrysanthemum, one of the most popular ornamental plants in the world, is renowned for its brilliant colors and multifarious flower types. Thousands of gorgeous chrysanthemum cultivars exist thanks to both traditional breeding techniques and its characteristic bud sporting. In this study, we identified a pink-to-yellow flower color-changed bud sport of the edible chrysanthemum cultivar ‘Pink Candy’. The bud variant and its parent plant bloomed at the same time, but with yellow- and pink-colored flowers, respectively. However, the two flower types exhibited strikingly different combinations and concentrations of primary and secondary metabolites, aromatic compounds, and pigments. Additionally, the expression patterns of key pigment biosynthesis genes, such as CmPAL (phenylalanine ammonia lyase), CmDFR (dihydroflavonol 4-reductase), CmF3H (flavanone 3′-hydroxylase), CmNXS (neoxanthin synthase) and CmCCD4 (carotenoid cleavage dioxygenase 4) were distinct between both flower types, helping to explain the color transformation of the mutant to some extent. Taken together, our results suggest a mechanism explaining the transformation of pink flowers to yellow flowers in the mutant bud sport. These results provide the foundation for the production of a novel chrysanthemum cultivar.