Flower color evolution within the Cichorieae (Asteraceae): the Flavonoid-3’5’-Hydroxylase

The blue flower color within the Cichorieae (Asteraceae) is thought to be determined by the presence of anthocyanins. The anthocyanin biosynthetic pathway is quite well studied. Two enzymes, flavonoid 3’ hydroxylase and flavonoid 3’, 5’ hydroxylase, determine the hydroxylation pattern of the anthocyaninswhich exhibit three classes: cyanidins (mainly in charge of redish/pink flowers), delphinidins (in charge of bluish flowers), and pelargonidins (one possibility to exhibit orange flower color). We here investigate flower color evolution in two closely related species of two different genera of the Cichorieae featuring yellow (Catananchelutea L.; Lactucaserriola L.) and bluish (Catananchecaerulea L., Lactucaperennis L.) flowers.Whereas, the yellow flowering species C. lutea and L. serrioladid notexpress F3’5’H it was possible to partially sequence the F3’5’H mRNA in C. caerulea and L. perennis. The q-RT PCR expression pattern revealed F3’5’Hto be expressed in different levels at different times and developmental stages during flower development of C. caerulea and L. perennis.The expression is preceding the petal coloration in the flowers. A phylogenetic analysis revealed high similarity of the bluish Cichorieae F3’5’H with other AsteraceaeF3’Hs and F3’5’H pinpointing to a neofunctionalization of this enzyme, to enable the Asteraceae to produce delphinidins again. In addition, the flavonoid composition was analyzed via LC-MS and HPLC. All four species contain caffeic acid, p-coumaric acid and 3’ hydroxylated flavonoids like quercetin derivatives. Delphinidin, Pelargonidin and Cyanidin were found in C. caerulea, while L. perennis only featured Pelargonidin and Cyanidin which was also found in much lower concentrations in L. serriola. Missing anthocyaninsin C. lutea might be indicative for an inactivation of the DFRenzyme(dihydroflavonol 4-reductase) in this species which might be yellow flowered due to carotinoids. Investigating enzyme activities will be the next step to reveal flower color evolution within the Cichorieae