Transcriptional Regulation of Lignin and Cellulose Biosynthesis in Brachypodium distachyon

The cell wall is a complex composite of polysaccharides, proteins, and lignin, with lignin and cellulose representing two of the most abundant bio-organic compounds on Earth. Much of what is currently understood about the transcriptional regulation of cell wall biosynthesis is from the study of Arabidopsis thaliana xylem vessels and fibers, yet this understanding may not be generalizable across land plants. The cell walls of grasses, including domesticated cereals that provide the majority of human calories and the perennials under development as biofuel energy crops, differ significantly in morphology and composition from the eudicot A. thaliana. We are taking a reverse genetics approach to understand the transcriptional regulation of secondary cell wall biosynthesis using the grass model system Brachypodium distachyon. In order to confirm transcription factor targets, we have silenced and confirmed candidate cellulose and lignin associated genes using artificial microRNAs. Using a yeast one-hybrid assay, we identified interactions between cis-regulatory regions of those genes and a collection of transcription factor proteins. In doing so, we seek to resolve the regulatory networks leading to cellulose and lignin synthesis.