Overexpression of SbMyb60 impacts phenylpropanoid biosynthesis and alters secondary cell wall composition in Sorghum bicolor

Erin D. Scully, Tammy Gries, Gautam Sarath, Nathan A. Palmer, Lisa Baird, Michelle J. Serapiglia, Bruce S. Dien, Akwasi A. Boateng, Zhengxiang Ge, Deanna L. Funnell-Harris, Paul Twigg, Thomas E. Clemente, Scott E. Sattler

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

The phenylpropanoid biosynthetic pathway that generates lignin subunits represents a significant target for altering the abundance and composition of lignin. The global regulators of phenylpropanoid metabolism may include MYB transcription factors, whose expression levels have been correlated with changes in secondary cell wall composition and the levels of several other aromatic compounds, including anthocyanins and flavonoids. While transcription factors correlated with downregulation of the phenylpropanoid biosynthesis pathway have been identified in several grass species, few transcription factors linked to activation of this pathway have been identified in C4 grasses, some of which are being developed as dedicated bioenergy feedstocks. In this study we investigated the role of SbMyb60 in lignin biosynthesis in sorghum (Sorghum bicolor), which is a drought-tolerant, high-yielding biomass crop. Ectopic expression of this transcription factor in sorghum was associated with higher expression levels of genes involved in monolignol biosynthesis, and led to higher abundances of syringyl lignin, significant compositional changes to the lignin polymer and increased lignin concentration in biomass. Moreover, transgenic plants constitutively overexpressing SbMyb60 also displayed ectopic lignification in leaf midribs and elevated concentrations of soluble phenolic compounds in biomass. Results indicate that overexpression of SbMyb60 is associated with activation of monolignol biosynthesis in sorghum. SbMyb60 represents a target for modification of plant cell wall composition, with the potential to improve biomass for renewable uses.

Original languageEnglish (US)
Pages (from-to)378-395
Number of pages18
JournalPlant Journal
Volume85
Issue number3
DOIs
StatePublished - Feb 1 2016

Keywords

  • C4 grass
  • bioenergy
  • lignin
  • monocot
  • monolignol
  • transgenic

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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    Scully, E. D., Gries, T., Sarath, G., Palmer, N. A., Baird, L., Serapiglia, M. J., Dien, B. S., Boateng, A. A., Ge, Z., Funnell-Harris, D. L., Twigg, P., Clemente, T. E., & Sattler, S. E. (2016). Overexpression of SbMyb60 impacts phenylpropanoid biosynthesis and alters secondary cell wall composition in Sorghum bicolor. Plant Journal, 85(3), 378-395. https://doi.org/10.1111/tpj.13112