Molecular characterization of EgMYB1, a putative transcriptional repressor of the lignin biosynthetic pathway

EgMYB1, a transcription factor of the large plant R2R3 MYB family was cloned from a Eucalyptus xylem cDNA library. EgMYB1 is preferentially expressed in the secondary xylem of stems and roots of Eucalyptus trees, and the corresponding protein is localized in the nucleus. EgMYB1 binds specifically the MBSIIG sites located in the promoters of lignin biosynthetic genes, and represses the transcription of these genes in planta. These results suggest that EgMYB1, a new member of subgroup 4, is a negative regulator of the lignin branch pathway and represents a new tool for controlling lignin profiles in plants.