Modified expression of ZmMYB167 in Brachypodium distachyon and Zea mays leads to increased cell wall lignin and phenolic content

Rakesh Bhatia, Sue Dalton, Luned Roberts, Odin Moron-Garcia, Rosario Iacono, Ondrej Kosik, Joe Gallagher, Maurice Bosch

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)
167 Downloads (Pure)

Abstract

One of the challenges to enable targeted modification of lignocellulosic biomass from grasses for improved biofuel and biochemical production lies within our limited understanding of the transcriptional control of secondary cell wall biosynthesis. Here, we investigated the role of the maize MYB transcription factor ZmMYB167 in secondary cell wall biosynthesis and how modified ZmMYB167
expression in two distinct grass model species affects plant biomass and growth phenotypes. Heterologous expression of ZmMYB167 in the C3 model system Brachypodium led to mild dwarf phenotypes, increased lignin (~7% to 13%) and S-lignin monomer (~11% to 16%) content, elevated concentrations of cell wall-bound p-coumaric acid (~15% to 24%) and reduced biomass sugar release
(~20%) compared to controls. Overexpression of ZmMYB167 in the C4 model system Zea mays increased lignin (~4% to 13%), p-coumaric acid (~8% to 52%) and ferulic acid (~13% to 38%) content but did not affect plant growth and development nor biomass recalcitrance. Taken together, modifying ZmMYB167
expression represents a target to alter lignin and phenolic content in grasses. The ZmMYB167 expression-induced discrepancies in plant phenotypic and biomass properties between the two grass model systems highlight the challenges and opportunities for MYB transcription factor-based genetic
engineering approaches of grass biomass.
Original languageEnglish
Article number8800
JournalScientific Reports
Volume9
Issue number1
Early online date19 Jun 2019
DOIs
Publication statusPublished - 01 Dec 2019

Keywords

  • Amino Acid Sequence
  • Brachypodium/genetics
  • Cell Wall/metabolism
  • Gene Expression Regulation, Plant
  • Lignin/metabolism
  • Phenols/metabolism
  • Phenotype
  • Plant Proteins/chemistry
  • Plants, Genetically Modified
  • Propanols/metabolism
  • Solubility
  • Sugars/metabolism
  • Zea mays/genetics

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