Journal of Cytology & Histology

Evidence for a Constitutive Cutinase in Ungerminated Conidia of Erysiphe necator Schwein

Abstract

Sylvain Schnee, Erwan Rougeux, Roger Pezet, Olivier Viret and Katia Gindro

Soluble proteins of ungerminated conidia of Erysiphe necator exhibited esterase and cutinase activities, and such hydrolytic activities were measured in the parietal protein fraction. However, histochemical localisation of esterase activity was detected upon further fungal development, as well in elongating germ tubes and in appressoria. The esterase activity was spectrophotometrically quantified using para-nitrophenylbutyrate as a substrate, and cutinase activity was determined using 3H-labelled cutin. Histochemical localisation was determined using indoxyl acetate as a substrate. Diisopropyl fluorophosphate was used as inhibitor of serine hydrolase. The role of a putative constitutive parietal cutinase in the ungerminated conidia of E. necator in adhesion to the host and differentiation of infective structures, as well as implications for successful penetration, are discussed.