Plants have evolved the inherent recalcitrance with chemical and structural complexity of their cell walls to resist deconstruction by pathogens. Although considerable progress has been made in understanding the basic organization and functions of plant cell wall components, due to the highly complex and dynamic nature of the plant cell wall, the variation in ultrastructural topochemistry and the establishment of its relationship with biomass conversion remain poorly understood. The plant cell wall is a layered construction composed mainly of cellulose microfibrils embedded in an amorphous matrix of hemicelluloses and lignin, thus both hemicelluloses and lignin have been considered to act as barrier elements during biomass deconstruction.<br/>Due to the higher spatial resolution (&lt;1nm) and specificity when combined with chemical staining and immunolabeling approaches, transmission electron microscopy (TEM) was employed to investigate the interrelation between cell wall topochemistry and cellulose accessibility. A comparative study was conducted to determine which component contributes to the major barrier in cellulase attack by localization of cellulase on both transverse and tangential wood sections after successive removal of hemicelluloses and lignin respectively. Highest cellulose accessibility and enzymatic hydrolysis efficiency were realized on sections with moderate hemicelluloses removal, suggesting that the increase of cellulose accessibility primarily occurs when exposing cellulose surface by getting rid of the hemicelluloses coating on it. The results not only contribute to improving the efficiency of biomass conversion, but will also help us to understand the assembly of the plant cell wall.<br/>Keywords: Plant cell wall, Topochemistry, Immunolabeling, Cellulose accessibility

In situ analysis of interrelation between topochemistry and cellulose accessibility in poplar cell walls

251st National Meeting (2016)

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