Spore surface glycoproteins of Colletotrichum lindemuthianum are recognized by a monoclonal antibody which inhibits adhesion to polystyrene

Conidia (spores) of Colletotrichum lindemuthianum, a fungal plant pathogen causing bean anthracnose, adhere to the aerial parts of host plants to init iate the infection process, These spores possess a fibrillar 'spore coat' a s well as a cell wall, In a previous study a mAb, UB20, was raised that rec ognized glycoproteins on the spore surface, In this study UB20 was used to localize and characterize these glycoproteins and to investigate their poss ible role in adhesion, Glycoproteins recognized by UB20 were concentrated o n the outer surface of the spore coat and, to a lesser extent, at the plasm a membrane/cell wall interface, Extraction of spores with hot water or 0.2% SDS resulted in removal of the spore coat, Western blotting with UB20 show ed that a relatively small number of glycoproteins were extracted by these procedures, including a major component at 110 kDa, Biotinylation of carboh ydrate moieties, together with cell fractionation, confirmed that these gly coproteins were exposed at the surface of the spores, In adhesion assays, > 90% of ungerminated conidia attached to polystyrene Petri dishes within 30 min, UB20 IgG at low concentrations inhibited attachment in an antigen-spe cific manner, This suggests that the glycoproteins recognized by this mAb m ay function in the initial rapid attachment of conidia to hydrophobic subst rata. Polystyrene microspheres bound selectively to the 110 kDa glycoprotei n in Western blots, providing further evidence that this component could me diate interactions with hydrophobic substrata.