title: MYB103 is required for FERULATE-5-HYDROXYLASE expression and syringyl lignin biosynthesis in Arabidopsis stems.
abstract: 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.
authors.affiliation: Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-90183, Umeå, Sweden.
authors.forename: David
authors.initials: D
authors.lastname: Öhman
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie, 9052, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Universiteit Gent, 9052, Gent, Belgium.
authors.forename: Brecht
authors.initials: B
authors.lastname: Demedts
authors.affiliation: Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-90183, Umeå, Sweden.
authors.forename: Manoj
authors.initials: M
authors.lastname: Kumar
authors.affiliation: Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-90183, Umeå, Sweden.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Gerber
authors.affiliation: Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-90183, Umeå, Sweden.
authors.forename: András
authors.initials: A
authors.lastname: Gorzsás
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie, 9052, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Universiteit Gent, 9052, Gent, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: Goeminne
authors.affiliation: Department of Chemistry, Umeå University, SE-90187, Umeå, Sweden.
authors.forename: Mattias
authors.initials: M
authors.lastname: Hedenström
authors.affiliation: Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
authors.forename: Brian
authors.initials: B
authors.lastname: Ellis
authors.affiliation: Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie, 9052, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Universiteit Gent, 9052, Gent, Belgium.
authors.forename: Wout
authors.initials: W
authors.lastname: Boerjan
authors.affiliation: Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-90183, Umeå, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Sundberg
mesh_terms: D017360:Arabidopsis / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000096:biosynthesis* / Q000502:physiology*; D002473:Cell Wall / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D008031:Lignin / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D018547:Plant Stems / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; C119922:MYB103 protein, Arabidopsis; C517318:SND1 protein, Arabidopsis; D014157:Transcription Factors; D002482:Cellulose; D008031:Lignin; D003577:Cytochrome P-450 Enzyme System; C097486:CYP84A1 protein, Arabidopsis