7-02: Cell Wall Glycan Dynamics During Primary to Secondary Wall Development in Poplar Stems

Plant biomass is considered as the major resource for renewable bioenergy. Cell walls are the principal component of plant biomass. Thus, understanding plant cell wall structure and biosynthesis is an important aspect of bioenergy research.  Poplar is one of the main target crops for bioenergy needs. Cell walls in poplar are significantly dynamic in their composition and structure varying considerably in different organs and cells. Further, cell walls in this plant also vary depending on developmental stages of organs. Hence, like any other plant cell walls, studying poplar plant cell walls, is challenging and requires efficient tools. A comprehensive suite of cell wall glycan-directed monoclonal antibodies are currently used as an excellent tools to study plant cell walls. Various studies have already employed these mAbs to study Poplar cell walls. Using two complementary techniques that employ these mAbs both in vitro and in vivo, here we report the variation in cell wall glycome in poplar stem internodes while transitioning from early developmental stage that harbor mostly primary walls to a mature developmental stage harboring mostly secondary walls. The broad range of mAbs used in this study allowed us to monitor changes occurring in most cell wall glycans.  The study revealed changes in extractability, composition and structure of cell wall polysaccharides especially hemicellulosic and pectic components in walls isolated from very young through mature internodes of poplar stem. Integrating the glycome data obtained here with currently available genome/transcriptome database can be instrumental in delineating the wall biosynthesis during polar stem development.