Öhman, David
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
Research article2013Peer reviewedOpen access
Öhman, David; Kumar, Manoj; Gerber, Lorenz; Gorzsas, Andras; Sundberg, Björn
The transcription factor MYB103 was previously identified as a member of the transcriptional network regulating secondary wall biosynthesis in xylem tissues of Arabidopsis, and was proposed to act on cellulose biosynthesis. It is a direct transcriptional target of the transcription factor SECONDARY WALL ASSOCIATED NAC DOMAIN PROTEIN 1 (SND1), and 35S-driven dominant repression or over-expression of MYB103 modifies secondary wall thickness. We identified two myb103 T-DNA insertion mutants and chemically characterized their lignocellulose by pyrolysis/GC/MS, 2D NMR, FT-IR microspectroscopy and wet chemistry. The mutants developed normally but exhibited a 70-75% decrease in syringyl (S) lignin. The level of guaiacyl (G) lignin was co-ordinately increased, so that total Klason lignin was not affected. The transcript abundance of FERULATE-5-HYDROXYLASE (F5H), the key gene in biosynthesis of S lignin, was strongly decreased in the myb103 mutants, and the metabolomes of the myb103 mutant and an F5H null mutant were very similar. Other than modification of the lignin S to G ratio, there were only very minor changes in the composition of secondary cell-wall polymers in the inflorescence stem. In conclusion, we demonstrate that F5H expression and hence biosynthesis of S lignin are dependent on MYB103.
F5H; lignin; MYB; secondary cell wall; transcription factor; xylem; Arabidopsis thaliana
Plant Journal
2013, volume: 73, number: 1, pages: 63-76
Publisher: WILEY-BLACKWELL
Biochemistry
Molecular Biology
https://res.slu.se/id/publ/42795