ABSTRACT
All plant cells are surrounded by polysaccharide-rich walls that play major roles in plant development, cellular and tissue-scale differentiation, and responses to the environment. Plant cell walls consist of several interconnected glycopolymers, including cellulose, hemicelluloses, glycoproteins, and the pectic matrix comprised of homogalacturonan, rhamnogalacturonan I, and rhamnogalacturonan II. Investigations of the spatial and temporal localisation of complex carbohydrate structures in plant cell walls have been hindered by our inability to detect and image specific glycan structural motifs. Monoclonal antibodies are highly specific and sensitive probes that can be used to detect and localise plant cell wall polysaccharides. There are now over 230 monoclonal antibodies available world-wide for cell wall studies. In this review, we summarise the global collection of such antibodies and what is known about the specific structures (epitopes) that these antibodies recognize in the various classes of plant cell wall polysaccharides and discuss how knowledge of their epitope specificity has been refined over time as analytical techniques improve. Finally, we summarise how plant glycan–directed monoclonal antibodies have been used to monitor fluctuations in plant cell wall composition and organisation in vitro and at the cellular level and have greatly contributed to our understanding of wall biology.
