Lectins in different members of the Sclerotiniaceae

Lectins were isolated from Sclerotinia minor, Sclerotinia trifoliorum, Sclerotinia miyabeana, Botrytis cinerea and three isolates of Sclerotinia sclerotiorum by affinity chromatography on immobilized d -galactose and characterized in some detail. The native lectins from all species are dimeric proteins composed of subunits of about 17 kDa which exhibit specificity towards methyl-α- d -galactopyranoside/ N -acetyl-α- d -galactosamine. Lectins from the different species can be distinguished by their serological behaviour in double immunodiffusion and ELISA assays. Whereas the lectins from the three S. sclerotiorum isolates are identical, those from S. trifoliorum, S. miyabeana and S. minor are closely related to but not identical to those from S. sclerotiorum . The lectin of B. cinerea is also related to the Sclerotinia lectins but to a lesser extent. In all the isolates the lectin content was very low in the undifferentiated mycelium but increased dramatically upon sclerotium development to reach maximal values in mature sclerotia where the lectin comprised up to 20% (w/w) of the total soluble sclerotial protein.