Monoclonal antibodies against diverse xyloglucan structures as probes for plant cell wall chemistry and ultrastructure

Abstract

The plant cell wall is a complex extracytoplasmic organelle whose structure and dynamics are poorly understood at the molecular scale. Traditional biochemical methods have documented plasticity in the cell wall properties during development and in response to stress, but are limited to characterizing bulk features. Alternatively, the structural discriminating power of monoclonal antibodies can be utilized to simultaneously probe the abundances and locations of molecular structures in muro at sub‐organellar resolution, and to examine cell wall components in vitro. We have generated more than 30 distinct monoclonal antibodies with a diverse range of specificities against xyloglucan, an abundant and structurally heterogenous class of carbohydrate polymer found in the plant cell walls. The binding specificities of these antibodies have been exhaustively characterized by ELISA‐based methods. The knowledge of the binding specificities allows structural interpretation of the immunolocalization patterns generated using these antibodies. Moreover, we have demonstrated the utility of these antibodies in structural classification of xyloglucans as well as in probing the biophysical properties of partially reconstituted plant cell walls, thus sheding light on the structure‐function relationships of this polysaccharide. This work is funded by NSF (DBI‐0421683) and DOE (DE‐FG02‐96ER20220).