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Synthesis of glucuronoxylan in higher and lower plants

is there conservation of the enzymatic machinery?

Hörnblad, Emma (2012). Synthesis of glucuronoxylan in higher and lower plants. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2012:8
ISBN 978-91-576-7692-4
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[Doctoral thesis]

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Abstract

The hemicellulose glucuronoxylan (GX) is the second most abundant polysaccharide
after cellulose in the secondary cell walls of angiosperms and contributes significantly
to the properties of wood as raw materials. Despite this, very little is known about the
biosynthesis of hemicellulose. The thesis is based on studies performed in
Physcomitrella patens, Arabidopsis thaliana, and Populus plants with the aim to
increase the understanding of glucuronoxylan synthesis, and with main focus on the
role of the IRX10 gene family.

A number of genes have proven to be involved in GX biosynthesis in Arabidopsis,
namely IRREGULAR XYLEM (IRX) 9, IRX14, IRX8, FRAGILE FIBER (FRA) 8 and
PARVUS. This thesis presents two new genes, IRX10 and its close homolog IRX10-
LIKE (L), which can now be added to the group of presumed GX biosynthesis genes. In
addition, identification and characterisation of three homologs (IRX9-L, IRX14-L and
F8H) of previously identified GX synthesis genes is described.

Complementation experiments and morphological studies confirmed redundancy
between the IRX9 and IRX9-L, IRX14 and IRX14-L, and the FRA8 and F8H pairs of
genes in Arabidopsis. A bioinformatics based approach has led to the identification of
four putative homologs in Populus trichocarpa (PtGT47A-1, PtGT47A-2, PtGT47D-1,
and PtGT47D-4) of AtIRX10, and one putative homolog from Physcomitrella
(PpGT47D). Experiments further confirmed functional conservation between the
Arabidopsis (IRX10) and Populus GT47A proteins, and partial functional conservation
between the Populus GT47D, the Physcomitrella GT47D and Arabidopsis IRX10
proteins.

The work supports the existence of an Arabidopsis GX backbone biosynthesis
complex in which AtIRX10 and AtIRX10-L form an essential component together with
AtIRX9 and AtIRX14. It also suggests that parts of the GX biosynthesis machinery are
conserved across embryophytes. Finally, work presented in this thesis indicates that the
IRX10 gene family has gone through a subfunctionalisation event during the evolution.

Authors/Creators:Hörnblad, Emma
Title:Synthesis of glucuronoxylan in higher and lower plants
Subtitle:is there conservation of the enzymatic machinery?
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :2012
Depositing date:27 January 2015
Volume:2012:8
Number of Pages:71
Papers/manuscripts:
NumberReferences
IWu, A.M., Rihouey, C., Seveno, M., Hörnblad, E., Singh, S.K., Matsunaga, T., Ishii, T., Lerouge, P. & Marchant, A. (2009). The Arabidopsis IRX10 and IRX10-LIKE glycosyltransferases are critical for glucuronoxylan biosynthesis during secondary cell wall formation. Plant Journal 57, 718-731.
IIWu A.M., Hornblad E, Voxeur A, Gerber L, Rihouey C, Lerouge P, Marchant A(2010). Analysis of the Arabidopsis IRX9/IRX9-L and IRX14/IRX14-L pairs of glycosyltransferase genes reveals critical contributions to biosynthesis of the hemicellulose glucuronoxylan. Plant Physiol, 153:542–554.
IIIEmma Hörnblad, Ai-Min Wu, András Gorzas, Lorenz Gerber, and Alan Marchant. The Populus GT47A-1 gene encodes a functional ortholog of the Arabidopsis IRX10 and IRX10-Like proteins supporting a partial conservation for glucuronoxylan biosynthesis between woody and herbaceous plants. (Manuscript)
IVHornblad, E., Ulfstedt, M., Ronne, H. and Marchant, A. (2013). Partial functional conservation of IRX10 homologs in Physcomitrella patens and Arabidopsis thaliana indicates an evolutionary step contributing to vascular formation in land plants. BMC Plant Biol. 13, 3.
Place of Publication:Umeå
Publisher:Institutionen för skoglig genetik och växtfysiologi, Sveriges lantbruksuniversitet
ISBN for printed version:978-91-576-7692-4
ISBN for electronic version:-
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F30 Plant genetics and breeding
F Plant production > F60 Plant physiology and biochemistry
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 404 Agricultural Biotechnology > Plant Biotechnology
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 404 Agricultural Biotechnology > Genetics and Breeding
Agrovoc terms:cell walls, hemicellulose, populus, arabidopsis thaliana, xylem, glycosyltransferases, lignification
Keywords:Glucuronoxylan, Wood formation, Secondary cell wall, Arabidopsis, Populus, Physcomitrella
URN:NBN:urn:nbn:se:slu:epsilon-e-2336
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-2336
ID Code:11815
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Genetics and Plant Physiology
External funders:FORMAS
Deposited By: PhD Emma Hörnblad
Deposited On:29 Jan 2015 10:18
Metadata Last Modified:27 Mar 2015 11:14

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