Abstract:

Flavonoids/anthocyanins, carotenoids and betalains are the main chemical substances for the coloration of flower petals. Among them, flavonoids/anthocyanins are the most widespread pigments determining the coloration of flower petals in most plants; whereas carotenoids play an important role in the color rendering of yellow to orange red petals in some specific plants. Betalains specially exists in some Caryophyllaceaes, including betaxanthins and betacyanins. At present, the molecular networks of their biosynthesis have been elucidated, and mainly controlled by a series of structural genes. Some regulators related to the pigment synthesis have been also identified in many plants. Moreover, the molecular breeding based on exogenous gene expression or endogenous gene editing have been successfully applied in the coloration improvements of some ornamental plants. In this review, the molecular basis, regulatory mechanism and molecular breeding application for the synthesis of three types of pigments in plants are systematically summarized. It is conducive for us to improve our understanding of the pigments synthesis-related regulatory network in plants, and expected to provide an theoretical support for future molecular breeding of flower colorations in ornamental plants.

Key words: flower coloration, flavonoids, carotenoids, betalains, molecular mechanism