Suppression of xylan endotransglycosylase PtxtXyn10A affects cellulose microfibril angle in secondary wall in aspen wood
2015 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 205, no 2, 666-681 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2015. Vol. 205, no 2, 666-681 p.
endotransglycosylase, growth stresses, hybrid aspen, Populus, secondary cell wall, wood formation, xylan, xylanase
IdentifiersURN: urn:nbn:se:kth:diva-160058DOI: 10.1111/nph.13099ISI: 000346584600024ScopusID: 2-s2.0-84919632563OAI: oai:DiVA.org:kth-160058DiVA: diva2:792958
FunderSwedish Research Council FormasSwedish Research CouncilVINNOVAKnut and Alice Wallenberg FoundationSwedish Foundation for Strategic Research
QC 201503052015-03-052015-02-132015-03-05Bibliographically approved