Suppression of xylan endotransglycosylase PtxtXyn10A affects cellulose microfibril angle in secondary wall in aspen wood

Marta Derba-Maceluch, Tatsuya Awano, Junko Takahashi, Jessica Lucenius, Christine Ratke, Inkeri Kontro, Marta Busse-Wicher, Ondrej Kosik, Ryo Tanaka, Anders Winzell, Asa Kallas, Joanna Lesniewska, Fredrik Berthold, Peter Immerzeel, Tuula T. Teeri, Ines Ezcurra, Paul Dupree, Ritva Serimaa, Ewa J. Mellerowicz*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Certain xylanases from family GH10 are highly expressed during secondary wall deposition, but their function is unknown. We carried out functional analyses of the secondary-wall specific PtxtXyn10A in hybrid aspen (Populus tremulaxtremuloides).PtxtXyn10A function was analysed by expression studies, overexpression in Arabidopsis protoplasts and by downregulation in aspen.PtxtXyn10A overexpression in Arabidopsis protoplasts resulted in increased xylan endotransglycosylation rather than hydrolysis. In aspen, the enzyme was found to be proteolytically processed to a 68kDa peptide and residing in cell walls. Its downregulation resulted in a corresponding decrease in xylan endotransglycosylase activity and no change in xylanase activity. This did not alter xylan molecular weight or its branching pattern but affected the cellulose-microfibril angle in wood fibres, increased primary growth (stem elongation, leaf formation and enlargement) and reduced the tendency to form tension wood. Transcriptomes of transgenic plants showed downregulation of tension wood related genes and changes in stress-responsive genes. The data indicate that PtxtXyn10A acts as a xylan endotransglycosylase and its main function is to release tensional stresses arising during secondary wall deposition. Furthermore, they suggest that regulation of stresses in secondary walls plays a vital role in plant development.

Original languageEnglish
Pages (from-to)666-681
Number of pages16
JournalNEW PHYTOLOGIST
Volume205
Issue number2
DOIs
Publication statusPublished - Jan 2015
MoE publication typeA1 Journal article-refereed

Keywords

  • endotransglycosylase
  • growth stresses
  • hybrid aspen
  • Populus
  • secondary cell wall
  • wood formation
  • xylan
  • xylanase
  • PLANT-CELL-WALL
  • CARBOHYDRATE-ACTIVE ENZYMES
  • ARABIDOPSIS-THALIANA
  • BARLEY-ALEURONE
  • ARABINOGALACTAN PROTEINS
  • POLYSACCHARIDE ANALYSIS
  • SCHIZOPHYLLUM-COMMUNE
  • CORTICAL MICROTUBULES
  • GLUCURONOYL ESTERASE
  • GEL-ELECTROPHORESIS

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