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

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. Lastly, 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.
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2]
  1. Univ. of Cambridge, Cambridge (United Kingdom). Dept. of Biochemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Biosciences Div.
  2. Univ. of Cambridge, Cambridge (United Kingdom). Dept. of Biochemistry.
Publication Date:
Grant/Contract Number:
AC02-05CH11231; BB/G016240/1; 251132; BB/K005537/1
Accepted Manuscript
Journal Name:
The Plant Journal
Additional Journal Information:
Journal Volume: 83; Journal Issue: 3; Journal ID: ISSN 0960-7412
Society for Experimental Biology
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; Xylan; IRX10L; IRX9L; IRX14; GUX3; primary wall; Arabidopsis thaliana
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1407271