A Long and Winding Road

We review the current understanding of the transcriptional control of polyphenol biosynthesis, which has been facilitated by the rapid expansion of available genome sequences over the last 10 years, particularly for species derived from more basal lineages of the plant kingdom. Transcriptional control has been built on the activity of R2R3Myb transcription factors, whose activity in regulating early versions of phenylpropanoid metabolism may have facilitated the emergence of plants onto land by providing protection from UV irradiation, water-proofing of cell walls and strengthening functionalities. Throughout land-plant evolution, the regulatory modules that developed for controlling polyphenol metabolism have been co-opted for the control of other processes in selected plant species.