ARABIDOPSIS-THALIANA AS A MODEL SYSTEM TO STUDY SYNTHESIS, STRUCTURE,AND FUNCTION OF THE PLANT-CELL WALL

The cell wall of higher plants has been studied in numerous species us ing methods of carbohydrate chemistry, biochemistry and cell biology p ortraying the wall as a dynamic structure composed of highly complex p olysaccharides and structural proteins encoded by multi-gene families. The recent discovery of proteins involved in cell wall loosening has provided opportunities to elucidate the mechanism of extension growth. Genetic tools have rarely been used to analyze the function of these proteins in vivo, or to identify genes involved in the synthesis of ce ll wall polysaccharides. It has recently been demonstrated that mutant s with changes in cell wall composition can be isolated in Arabidopsis thaliana opening possibilities to clone genes involved in the synthes is or modification of cell wall material via map-based approaches. The number of Arabidopsis mutants in cell wall synthesis is very limited, suggesting that novel screening procedures are required to come close r to the goal of saturating cell wall biosynthetic pathways. The avail ability of large numbers of expressed sequence tags in combination wit h collections of T-DNA and transposon-tagged Arabidopsis lines offers a considerable potential for the genetic characterization of cell wall -related genes which can be identified via database searches. The rece nt identification of Arabidopsis genes involved in the synthesis of ce ll wall precursors, and the discovery of plant homologs to bacterial c ellulose synthases offer numerous and exciting possibilities for the g enetic dissection of cell wall synthesis in higher plants using Arabid opsis thaliana as a model system. (C) Elsevier, Paris.