VIEW ARTICLE

Catabolite Repression of Polygalacturonase, Pectin Lyase, and Cellulase Synthesis in Penicillium expansum. D. H. Spalding, Research Plant Pathologist, USDA, ARS, Market Quality Research Division, 13601 Old Cutler Road, Miami, Florida 33158; J. M. Wells(2), and D. W. Allison(3). (2)Research Plant Pathologist, USDA, ARS, Market Quality Research Division, 13601 Old Cutler Road, Miami, Florida 33158; (3)Student trainee, Plant Industry Station, Beltsville, Maryland 20705. Phytopathology 63:840-844. Accepted for publication 8 January 1973. DOI: 10.1094/Phyto-63-840.

Production of pectin lyase (PL), polygalacturonase (PG), and carboxymethylcellulase (Cx), by Penicillium expansum in a 0.5% pectin-polypectate mineral salts medium, was repressed by 0.1 M arabinose, mannose, galactose, glucose, sucrose, raffinose, galacturonic acid, and glutamic acid. Raffinose and glutamic acid were equally repressive at 0.03 M and 0.1 M; affected PG, PL, and Cx equally; and were effective even when added after enzyme-production began. Repression reduced the maceration of apple tissue by culture filtrates. Production of PG, PL, and Cx was high in dialyzed apple medium and was repressed by raffinose. In nondialyzed apple medium, production of enzymes was minimal, possibly repressed by sugars or other natural constituents of the apple tissue.