Transcriptional Regulators of Suberin Biosynthesis in Arabidopsis thaliana

The root endodermis of Arabidopsis thaliana contains suberin, a cell wall-associated hydrophobic polymer that helps control the movement of water and solutes into the stele. Unfortunately, there are gaps in our knowledge on the regulation of suberin biosynthesis. This study demonstrates that transcription factors MYB41, MYB53, MYB92, and MYB93 can activate the transcription of suberin biosynthesis genes through their promoter upstream regions. Fragments of the promoter upstream region for FAR4, a suberin biosynthetic enzyme, were important for specific expression in the root endodermis. However, no evidence of direct binding by MYB53, MYB92, and MYB93 to these FAR4 promoter upstream region fragments was found via Y1H assay. The promoter upstream region of the transcription factor WRKY56 was found to be transcriptionally activated by MYB41, MYB53, MYB92, and MYB93. While, WRKY56 has limited impact on root suberin deposition under non-stress conditions, bioinformatic evidence suggests that WRKY56 has a role under stress conditions.