Cracking the “Sugar Code”: A Snapshot of N- and O-Glycosylation Pathways and Functions in Plants Cells

STRASSER, RICHARD; SEIFERT, GEORG; DOBLIN, MONIKA S.; JOHNSON, KIM L.; RUPRECHT, COLIN; PFRENGLE, FABIAN; BACIC, ANTONY; ESTEVEZ, JOSÉ M.

Frontiers in Plant Science

Frontiers

Año: 2021 vol. 12

Glycosylation is a fundamental co-translational and/or post-translational modificationprocess where an attachment of sugars onto either proteins or lipids can altertheir biological function, subcellular location and modulate the development andphysiology of an organism. Glycosylation is not a template driven process andas such produces a vastly larger array of glycan structures through combinatorialuse of enzymes and of repeated common scaffolds and as a consequence itprovides a huge expansion of both the proteome and lipidome. While the essentialrole of N- and O-glycan modifications on mammalian glycoproteins is already welldocumented, we are just starting to decode their biological functions in plants.Although significant advances have been made in plant glycobiology in the lastdecades, there are still key challenges impeding progress in the field and, assuch, holistic modern high throughput approaches may help to address theseconceptual gaps. In this snapshot, we present an update of the most commonO- and N-glycan structures present on plant glycoproteins as well as (1) theplant glycosyltransferases (GTs) and glycosyl hydrolases (GHs) responsible for theirbiosynthesis; (2) a summary of microorganism-derived GHs characterized to cleavespecific glycosidic linkages; (3) a summary of the available tools ranging frommonoclonal antibodies (mAbs), lectins to chemical probes for the detection of specificsugar moieties within these complex macromolecules; (4) selected examples of NandO-glycoproteins as well as in their related GTs to illustrate the complexity on their mode of action in plant cell growth and stress responses processes, and finally (5) we present the carbohydrate microarray approach that could revolutionize the way in which unknown plant GTs and GHs are identified and their specificities characterized.