Biosynthesis of plant cell walls

Abstract

The cell wall plays a major role in determining the expansion, growth and shape of plant cells, and thus of the plant itself. Additionally, cell wall breakdown products are used as developmental signals. Moreover, the cell wall is in the front line of defence, forming a signifi cant barrier to penetration by pathogens and pathogen vectors. There is great diversity in the polysaccharides of the cell wall which is composed of cellulose microfi brils, with the matrix polysaccharides, pectins and hemicelluloses binding non-covalently to the cellulose molecules, crosslinking them in an extensive network. Agronomically, a variety of industries are reliant on cell wall polysaccharides, particularly in the processing of foods. However, surprisingly little is known about their precise role(s) in planta. This is even more apparent considering that the polysaccharide composition of different cell types and organs differs, and changes over time, suggesting that the polysaccharides have a variety of specifi c roles. With the completion of genome sequencing projects in model and commercially-important plant species, signifi cant progress has been made in elucidating the proteins responsible for cell wall synthesis, leading to potential biotechnological applications. Key words: Arabidopsis thaliana, cell wall,