Figure 10.

Proposed modification strategies of flavonoids, carotenoids and chlorophyll metabolic pathways in tepals of Chinese narcissus to acquire functional color pigments. (A) Reconstruction of flavonoids metabolic pathway to acquire functional anthocyanin pigments (cyanidin, delphinidin, and pelargonodin); (B) Modification of expression of some critical genes in carotenoids metabolic pathway to acquire sufficient functional carotenoids pigments; (C) Restriction of gene expression in chlorophyll breakdown and heme formation sub-pathways meanwhile increase gene expression in ALA formation, Proto IX formation and chlorophyll formation sub-pathways may produce flower with green tepal. The specific suggestions for modifications of each pathway are listed at the bottom of each section. Black filled arrows indicate the substance metabolism directions; red “X” means the decrease or deletion of the expression of negative gene(s) or sub-pathways in order to remodel the main pathway.