Glycan microarrays of cell wall polysaccharides in functional genomics – WALLARRAY-II

The project “WallArray” was submitted to the ANR call for proposals entitled “Genomics” in April, 2008. In this framework, the project was funded for a feasibility study over one year. The obtained results confirm the objectives initially proposed by the five partners involved in the project. The new project is based on the main results of the feasibility study, and develops new technical solutions and new propositions to achieve the objectives. The submission of the project WallArray 2 to the call for proposals “Genomics, Plant Biotechnologies” thus joins in the continuity of the previous project. It brings together the same consortium of research teams from the public institutes of CEA, CNRS and INRA, from the universities of Grenoble and Toulouse, and from the private company Genoptics. They develop researches in the fields of physico-chemistry, chemistry, structural biology, and plant biology.

Cell walls are natural composite structures, mostly made of high molecular weight polymers (polysaccharides and lignins) and proteins interacting with these polymers. Cell walls are dynamic structures involved in cell division, expansion, differentiation and adhesion governing plant morphology. They are also the sources of oligosaccharide signals for molecular recognition to control developmental processes and even the outcome of plant-microorganism interactions. In recent years, significant headway in genomics, proteomics, glycomics and bioinformatics increased our knowledge of cell wall-related genes and proteins, in particular those related to the modification and interaction with polysaccharides. The function of only few of them was experimentally proven. Therefore, structural and functional aspects concerning the interplay of the cell wall glycome (defined as a set of carbohydrate structures present in the cell wall) and the cell wall proteome (set of proteins) are of great interest to understand cell wall dynamics and signalling.
The aim of the project is to develop carbohydrate microarrays of plant cell wall polysaccharides as innovative tools for screening cell wall carbohydrate-binding proteins (CBPs) and assessing their specificity. The functional and structural data obtained by the consortium will be integrated into existing database freely opened to the scientific community (glyco3d). Also, the data will be integrated to design softwares for the prediction of protein and carbohydrate structures. These studies should ultimately lead to more predictive capabilities in protein/carbohydrate interactions. The project brings together a diverse set of established novel technologies which were implemented during the feasibility study: from the generation of glycan libraries and their linking to a surface, to the production of carbohydrate binding proteins and the analysis of carbohydrate-protein binding by surface plasmon resonance imaging.
Understanding the carbohydrate-protein interactions at the plant cell surfaces complements data of the glycome and the proteome, and represents an essential step in the post-genomic area. On the other hand, plant cell walls represent the most abundant components of biomass. The carbohydrate-containing materials (cellulose, pectins) have been exploited by industries for food and non-food uses throughout centuries. With the recognition of the carbohydrates as carriers of biological properties, glyco-biotechnology companies have emerged. The carbohydrate microarrays will be a useful tool for discovering new polysaccharides acting enzymes, elaborating new materials, and engineering new plants.