Plant cell walls are complex structures whose composition and architecture are important to various cellular activities. Plant cell elongation requires a high level of rearrangement of the cell wall polymers to enable cell expansion. However, the cell wall polysaccharides dynamics during plant cell elongation is poorly understood. This PhD project aims to elucidate the cell wall compositional and structural change during cell elongation by using Comprehensive Microarray Polymer Profiling (CoMPP), microscopic techniques and molecular modifications of cell wall polysaccharide.
Developing cotton fibre, pea and Arabidopsis thaliana were selected as research models to investigate different types of cell elongation, developmental elongation and tropism elongation. A set of comprehensive analysis covering 4 cotton species and 11 time points suggests that non-cellulosic polysaccharides contribute to dynamics of primary cell wall during cotton fibre developmental elongation. Extensin arabinosyl side chain length is modified during cotton fibre development and the content of extensins is indicative to fibre quality. In tropism elongation research, we detected content change of -1, 4-galactan in auxin induced elongation on pea stem and a possible physiological correlation between galactan and extensins. To further characterize the role of -1,4-galactan in elongation we used Virus-Induced Gene Silencing (VIGS) technology to downregulate the PsGALS2B gene - a pea orthologue of Arabidopsis GT92 galactosyltransferase involved in -1,4-galactan synthesis. The silenced plants showed severe defects in elongation ubiquitously. Both developmental and tropism elongation research point out that -1, 4-galactan plays important role in plant cell elongation