Rapid adhesion of Stagonospora nodorum spores to a hydrophobic surface requires pre-formed cell surface glycoproteins

Adhesion of fungal pathogens to leaf surfaces is an important first step in the infection process. Previous work on Stagonospora nodorum, a major necrotrophic pathogen of wheat and other cereals, has shown that conidia attach rapidly to a hydrophobic surface and this is followed by the active secretion of extracellular matrix material to consolidate adhesion. In this paper the role of pre-formed spore surface glycoproteins in the rapid adhesion of S. nodorum conidia to an artificial surface, polystyrene, has been investigated. Sodium dodecyl sulphate (SDS) and the enzymes chitinase and lyticase have been used to release cell wall glycoproteins from spores and these have been identified using SDS polyacrylamide gel electrophoresis (PAGE) and Western blotting. Labelling with fluorescently tagged lectins has also been used to study the spore surface. The results show that there are a small number of glycoproteins non-covalently and covalently attached to other components in the spore wall, which is not a uniform structure. The effects of proteases, lectins, and other treatments of spores in an adhesion assay have been used to show that pre-formed glycoproteins are involved in rapid adhesion to a hydrophobic surface. There is also evidence for a rapid release of glycoproteins by spores that is also involved in adhesion and this is not an active process.