Production of pectic and cellulolytic enzymes by aggressive and non-aggressive strains of Ophiostoma ulmi

Abstract

Polygalacturonase (PG) and cellulase (Cx) production byOphiostoma ulmi was determined in growth media of pH 3.0. 5.0 and 7.0 containing ethanol-extracted or freeze-dried elm wood. PG activity was low or absent in cultures of pH 7.0. Cx production was not affected by differences in pH. Production of PG was much higher with freeze-dried wood than with ethanol-extracted wood. No differences in PG and Cx activities were found between cultures with freeze-dried wood of resistant or of susceptible elms. No correlation was found between PG and Cx production and aggressiveness of strains ofO. ulmi. The decrease of PG activity during incubation with increasing pH, was not due to the formation of PG inhibitors.