One Poplar 5-Enolpyruvylshikimate 3-Phosphate (EPSP) Synthase Moonlight as Transcriptional Repressor to Regulate Lignin Biosynthesis

The Science

Understand how lignin biosynthesis is regulated in poplar.

The Impact

• EPSP synthase shown to co-function as a transcriptional repressor.
• PtrEPSP-TF overexpressing poplars had increased lignin deposition, accumulation of lignin-related metabolites, and expression of lignin-related genes.
• PtrEPSP-TF directly represses the expression of PtrhAT. PtrhAT then directly represses the expression of PtrMYB021. Consequently, PtrEPSP-TF positively regulates PtrMYB021 expression and lignin biosynthesis in poplar.

Summary

• Used GWAS to define the linkage of PtrEPSP-TF and lignin biosynthesis.
• Validated linkage by assessing PtrEPSP-TF overexpressing poplars for lignin deposition, secondary metabolism, and gene expression levels.
• Investigated underlying molecular mechanism by protoplast-based assays.

Principal Investigator(s)

Xie Ming
Oak Ridge National Laboratory

References

Xie, M. et al. “A 5-enolpyruvylshikimate 3-phosphate synthase functions as a transcriptional repressor in Populus.” The Plant Cell 30(7), 1645–1660 (2018). [DOI:10.1105/tpc.18.00168]