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An unusual xylan in Arabidopsis primary cell walls is synthesised by GUX3, IRX9L, IRX10L and IRX14.


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Authors

Mortimer, Jenny C 
Faria-Blanc, Nuno 
Yu, Xiaolan 
Sorieul, Mathias 

Abstract

Xylan is a crucial component of many plant primary and secondary cell walls. However, the structure and function of xylan in the dicotyledon primary cell wall is not well understood. Here, we characterized a xylan that is specific to tissues enriched in Arabidopsis primary cell walls. Unlike previously described xylans, this xylan carries a pentose linked 1-2 to the α-1,2-d-glucuronic acid (GlcA) side chains on the β-1,4-Xyl backbone. The frequent and precisely regular spacing of GlcA substitutions every six xylosyl residues along the backbone is also unlike that previously observed in secondary cell wall xylan. Molecular genetics, in vitro assays, and expression data suggest that IRX9L, IRX10L and IRX14 are required for xylan backbone synthesis in primary cell wall synthesising tissues. IRX9 and IRX10 are not involved in the primary cell wall xylan synthesis but are functionally exchangeable with IRX9L and IRX10L. GUX3 is the only glucuronyltransferase required for the addition of the GlcA decorations on the xylan. The differences in xylan structure in primary versus secondary cell walls might reflect the different roles in cross-linking and interaction with other cell wall components.

Description

Keywords

Arabidopsis thaliana, GUX3, IRX10L, IRX14, IRX9L, Xylan, primary wall, Arabidopsis, Arabidopsis Proteins, Cell Wall, Glycosyltransferases, Pentosyltransferases, Xylans

Journal Title

Plant J

Conference Name

Journal ISSN

0960-7412
1365-313X

Volume Title

83

Publisher

Wiley
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/G016240/1)
Biotechnology and Biological Sciences Research Council (BB/K005537/1)
European Commission (251132)
The work presented in this paper was supported by grants from the BBSRC: BB/G016240/1 BBSRC Sustainable Energy Centre Cell Wall Sugars Programme (BSBEC) and grant BB/K005537/1. JCM’s work at the Joint BioEnergy Institute was supported by the Office of Science, Office of Biological and Environmental Research, of the U.S. Department of Energy under Contract No. DE -AC02-05CH11231. NFB was supported by a PhD studentship from the Portuguese Foundation for Science and Technology. AN was supported by a summer studentship award from the Biochemical Society. The authors are grateful to the European Community’s Seventh Framework Programme SUNLIBB (FP7/2007-2013) under the grant agreement no 251132.