In situ analysis of cell wall polysaccharides in stems of Miscanthus species

Plant cell walls are important cellular components underpinning growth and development and, in addition, can be important sources of biomass and renewable energy. Miscanthus species are fast growing plants with high
biomass yield. Miscanthus x giganteus is the sterile hybrid between Miscanthussinensis and Miscanthus sacchariflorus, with a faster and taller growth than its parents. A range of monoclonal antibodies have been used
in immunofluorescence in situ analyses to study the occurrence and interactions of non-cellulosic polysaccharides in Miscanthus species. In this study, it was observed that heteroxylans and mixed-linkage-glucans (MLGs) were
abundant in the cell walls of stems of Miscanthus species and that their distributions varied in relation to the vascular cells and interfascicular parenchyma. There were also clear differences in polysaccharide patterning
between the three species. Detection of pectic-homogalacturonan (HG) epitopes was restricted to the intercellular spaces of parenchyma regions and, notably, the high methyl ester LM20 HG epitope was specifically abundant in the pith parenchyma cell walls of M. x giganteus in comparison to its parents. It has been reported that some cell wall polymer probes cannot access polymers, because they may be masked by other polymers. It was found in this study that xyloglucan and pectic-galactan were masked by xylan and/or MLG in certain cell wall regions. The heterogeneity of Miscanthus cell wall structures and molecular architectures found in this study are an important basis for understanding Miscanthus cell wall properties and will also inform potential strategies for the efficient deconstruction of Miscanthus biomass.