Specific genes of cytochrome P450 monooxygenases are implicated in biosynthesis of caffeic acid metabolites in rolC-transgenic culture of Eritrichium sericeum

Expression of rol agrobacterial oncogenes in plant cell cultures is known to result in activation of secondary metabolite biosynthesis. In the present work, we show that rolC can activate expression of key genes of secondary metabolism using the rolC-transgenic culture of Eritrichium sericeum producing caffeic acid metabolites (rosmarinic acid and rabdosiin) as an example. Increased content of rosmarinic acid in the rolC-transformed callus culture resulted from transcriptional activation of members of the CYP98 family of plant cytochrome P450-containing monooxygenase genes. The rolC gene expression led to increased transcript abundance of the CYP98A3 subfamily members, which are closely related homologs of CYP98A6 of Lithospermum erythrorhizon and are known to be key genes in rosmarinic acid biosynthesis. In contrast, expression of other CYP genes, such as CYP98A1 and CYP98A2, which are not implicated in rosmarinic acid biosynthesis, was not activated in the rolC-transformed calluses. These results are indicative of selective effect of rolC on transcription of particular genes implicated in secondary metabolism.