Journal
FRONTIERS IN PLANT SCIENCE
Volume 12, Issue -, Pages -Publisher
FRONTIERS MEDIA SA
DOI: 10.3389/fpls.2021.737690
Keywords
xylan (hemicellulose); glucuronoxylan; atomic force micorscopy (AFM); secondary cell wall (SCW); cell wall mechanical properties; irregular xylan mutants (irx); cellulose deposition; cellulose arrangement
Categories
Funding
- NSF [NSF CBET 1336622]
- EU [841703]
- US Department of Energy, Office of Science, Office of Biological and Environmental Research [DE-SC0019072]
- Great Lakes Bioenergy Research Center [DE-SC0018409]
- U.S. Department of Energy (DOE) [DE-SC0019072] Funding Source: U.S. Department of Energy (DOE)
- Marie Curie Actions (MSCA) [841703] Funding Source: Marie Curie Actions (MSCA)
Ask authors/readers for more resources
Plant biomass, particularly the secondary cell wall (SCW) formation of cell types in eudicot plants, involves a well-understood molecular interaction between glucuronoxylan (GX) and cellulose. This study characterizes cellulose microfibril organization in GX mutants, revealing the critical role of normal GX composition in cellulose bundle formation and overall cellulose organization within SCWs. Visualized through scanning electron microscopy and atomic force microscopy, findings suggest significant perturbations in cellulose network and nanomechanical properties, impacting enzymatic hydrolysis.
Plant biomass represents an abundant and increasingly important natural resource and it mainly consists of a number of cell types that have undergone extensive secondary cell wall (SCW) formation. These cell types are abundant in the stems of Arabidopsis, a well-studied model system for hardwood, the wood of eudicot plants. The main constituents of hardwood include cellulose, lignin, and xylan, the latter in the form of glucuronoxylan (GX). The binding of GX to cellulose in the eudicot SCW represents one of the best-understood molecular interactions within plant cell walls. The evenly spaced acetylation and 4-O-methyl glucuronic acid (MeGlcA) substitutions of the xylan polymer backbone facilitates binding in a linear two-fold screw conformation to the hydrophilic side of cellulose and signifies a high level of molecular specificity. However, the wider implications of GX-cellulose interactions for cellulose network formation and SCW architecture have remained less explored. In this study, we seek to expand our knowledge on this by characterizing the cellulose microfibril organization in three well-characterized GX mutants. The selected mutants display a range of GX deficiency from mild to severe, with findings indicating even the weakest mutant having significant perturbations of the cellulose network, as visualized by both scanning electron microscopy (SEM) and atomic force microscopy (AFM). We show by image analysis that microfibril width is increased by as much as three times in the severe mutants compared to the wild type and that the degree of directional dispersion of the fibrils is approximately doubled in all the three mutants. Further, we find that these changes correlate with both altered nanomechanical properties of the SCW, as observed by AFM, and with increases in enzymatic hydrolysis. Results from this study indicate the critical role that normal GX composition has on cellulose bundle formation and cellulose organization as a whole within the SCWs.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available