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Sammanfattning

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.

Nyckelord

F5H; lignin; MYB; secondary cell wall; transcription factor; xylem; Arabidopsis thaliana

Publicerad i

Plant Journal
2013, volym: 73, nummer: 1, sidor: 63-76
Utgivare: WILEY-BLACKWELL

SLU författare

UKÄ forskningsämne

Biokemi
Molekylärbiologi

Publikationens identifierare

  • DOI: https://doi.org/10.1111/tpj.12018

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/42795