R2R3 MYB proteins constitute one of the largest plant transcription factor clades and regulate diverse plant-specific processes. Several R2R3 MYB proteins act as regulators of secondary cell wall (SCW) biosynthesis in Arabidopsis thaliana (At), a dicotyledenous plant. | Comparative genomic analysis of the R2R3 MYB secondary cell wall regulators of Arabidopsis poplar rice maize and switchgrass