GENETICS OF PHYTOPATHOGENIC FUNGI: PECTOLYTIC ENZYMES OF VIRULENT AND AVIRULENT STRAINS OF THREE PHYTOPATHOGENIC PENICILLIA

Abstract

Culture filtrates from a virulent and an avirulent strain of each of three phytopathogenic species of Penicillium grown in a defined medium to which were added different sources of organic carbon had endopolygalacturonase (endoPG) and exopolygalacturonase (exoPG), but neither detectable pectin methylesterase nor pectin lyase activity. Extracts from diseased tissue of oranges inoculated with P. italicum or P. digitatum and from diseased tissue of apples inoculated with P. expansum, but not from healthy fruits, had endoPG and exoPG activity. Culture filtrates and extracts of diseased tissue were subjected to vertical starch-gel zone electrophoresis. The number, location (anodic, cathodic), electrophoretic mobility, and relative activity of sites of endoPG or exoPG activity were determined by the species, virulence or avirulence of the strain, source of organic carbon, and gel pH.