Plants rely on the biosynthesis of L-Phenylalanine as building block for the synthesis of
proteins but also as precursor for a tremendous range of plant-derived compounds
essential for its grown, development and defense. Polymerization of secondary cell wall
in trees involves the massive biosynthesis, among others, of the Phe-derived compound
lignin. Thus, these plants require an accurate metabolic coordination between Phe and
lignin biosynthesis to ensure its normal development. We have here identified that the
pine arogenate dehydratase, whose enzyme activity limits the biosynthesis of Phe in
plants, is transcriptionally regulated through direct interaction with PpMyb8. We have
also shown that this transcription factor is directly involve in secondary cell wall
biogenesis and cell death processes. Together these results indicate that a single
transcription factor coordinates lignin accumulation and the proper biosynthesis of its
essential precursor L-Phe.