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Function of MAP20 and MYB103 in cellulose and lignin formation of xylem secondary cell walls

Öhman, David (2014). Function of MAP20 and MYB103 in cellulose and lignin formation of xylem secondary cell walls. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2014:4
ISBN 978-91-576-7956-7
eISBN 978-91-576-7957-4
[Doctoral thesis]

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Abstract

Lignocellulose from trees and other crops will have tremendous impact on the next generation of sustainable biofuels and biomaterials. To take advantage of modern breeding tools, it is therefore important to understand the genetic and molecular regulation underlying secondary cell wall formation. Here, functional analysis was performed on two genes specifically involved in secondary cell wall formation, using Arabidopsis and Populus as model species.

PttMAP20 was earlier identified as a wood-specific microtubule-associated protein in hybrid aspen, but not functionally assessed [Rajangam et al. (2008). Plant Physiology, pp. 1283–1294]. In this thesis, AtMAP20 was found to be generally expressed in secondary wall forming cell types in Arabidopsis, including xylem cells, and its binding to microtubules was confirmed. A domain-mapping study showed that its central TPX2 domain, together with the N- and/or C-terminal domain, is required for complete microtubule binding. Overexpression of AtMAP20 induced shorter roots and right-handed twisting, mimicking treatment with the microtubule-stabilizing drug taxol. Loss-of-function map20 mutants had longer etiolated hypocotyls and altered cell wall chemistry. This phenotype was interpreted as resulting from mechanical weakening in the secondary walls of their spiral protoxylem vessels. In line with this, overexpression of PttMAP20 in hybrid aspen affected cellulose microfibril angle. Taken together, MAP20 is a novel microtubule-stabilizing protein, specifically active during secondary cell wall formation and important for the patterning of cellulose microfibrils.

MYB103 is a xylem-specific transcription factor, previously demonstrated to be directly activated by the secondary wall NAC master switches SND1/NST1 and VND6/VND7 [Zhong et al. (2008). Plant Cell, pp. 2763–2782]. This thesis demonstrates that loss-of-function Arabidopsis myb103 mutants have reduced levels of syringyl lignin in their basal stems. This was compensated for by an increase in guaiacyl lignin, resulting in a modified syringyl to guaiacyl ratio. The altered lignin composition, characterized by Py/GC-MS, FT-IR microspectroscopy and 2D NMR, was caused by a suppression of F5H, a key gene in syringyl lignin biosynthesis. Thus, it is concluded that MYB103 is required for F5H expression.

Taken together, this thesis presents novel knowledge on function of genes important for secondary cell wall formation and, hence, wood formation. These findings have the potential to improve wood characteristics to benefit forest growers and industries.

Authors/Creators:Öhman, David
Title:Function of MAP20 and MYB103 in cellulose and lignin formation of xylem secondary cell walls
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :23 May 2014
Volume:2014:4
Number of Pages:105
Papers/manuscripts:
NumberReferences
I.Manoj Kumar, Sergey Miroshnichenko, David Öhman, Ines Ezcurra, Björn Sundberg and Edouard Pesquet. MAP20, a Novel Plant Specific Stabilizing Microtubule Associated Protein (Manuscript).
II.David Öhman, Sergey Miroshnichenko, Delphine Menard, Manoj Kumar, Lorenz Gerber, András Gorzsás, Edouard Pesquet and Björn Sundberg. AtMAP20 is specifically expressed in cell types with secondary walls and involved in cell wall composition and structure (Manuscript).
III.David Öhman*, Brecht Demedts*, Manoj Kumar, Lorenz Gerber, András Gorzsás, Geert Goeminne, Mattias Hedenström, Brian Ellis, Wout Boerjan and Björn Sundberg (2013). MYB103 is required for FERULATE-5-HYDROXYLASE expression and syringyl lignin biosynthesis in Arabidopsis stems. The Plant Journal 73, 63–76.
IV.Lorenz Gerber, David Öhman, Viet Mai Hoang, Thai Bui, Manoj Kumar, Philippe Ranocha, Deborah Goffner and Björn Sundberg. High-throughput microanalysis of large ligno-cellulosic sample sets by Pyrolysis-Gas Chromatography/Mass Spectrometry (Submitted to New Phytologist).
Place of Publication:Umeå
Publisher:Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-7956-7
ISBN for electronic version:978-91-576-7957-4
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F60 Plant physiology and biochemistry
F Plant production > F62 Plant physiology - Growth and development
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Biochemistry and Molecular Biology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Cell Biology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Botany
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Bioinformatics and Systems Biology (methods development to be 10203)
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Wood Science
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 404 Agricultural Biotechnology > Plant Biotechnology
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 405 Other Agricultural Sciences > Renewable Bioenergy Research
Agrovoc terms:populus, arabidopsis thaliana, microtubules, cell walls, wood formation, genes, transcription factors, xylem, lignins, lignocellulose
Keywords:MAP20, MYB103, microtubule-associated protein (MAP), transcription factor, secondary cell wall, xylem, lignin, cellulose, Arabidopsis thaliana, Populus
URN:NBN:urn:nbn:se:slu:epsilon-e-1916
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-1916
ID Code:11211
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Genetics and Plant Physiology
External funders:FORMAS
Deposited By: Dr David Öhman
Deposited On:22 May 2014 06:06
Metadata Last Modified:02 Dec 2014 11:06

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