VISUALIZATION OF MATERIALS RELEASED FROM ADHERED, UNGERMINATED CONIDIA OF COLLETOTRICHUM-GRAMINICOLA

Conidia of Colletotrichum graminicola that had adhered to substrata re leased materials that were examined by scanning electron microscopy (S EM) or by light microscopy after staining for protein or carbohydrate. SEM of conidia that had adhered to dimethyldichlorosilane-coated or p olystyrene-coated glass revealed that material had been released onto the substratum surface where the conidia had been in contact with the surface. Gold/silver staining of adhered conidia revealed patterns of staining that indicated that proteinaceous materials had been released from the lip of the conidium and at the site of contact of the conidi um with the substratum (contact interface). When adhered conidia were stained with fluorescein (FITC)-conjugated lectins, only FITC-concanav alin A (FITC-ConA) labelled carbohydrates at the contact interface. FI TC-ConA also bound to materials that surrounded conidia that had adher ed. Different patterns of labelling by other FITC-conjugated lectins w ere also observed, indicating that the material released from a conidi um has a specific spatial arrangement around the conidium. Both the Co nA lectin and the Lens culinaris agglutinin lectin blocked adhesion, i ndicating that the material released from conidia contained glucose an d/or mannose. Together, these results suggest that the material associ ated with adhered conidia is composed of glycoprotein.