Effect of tannins and phenolic extracts from plant roots on the production of cellulase and polygalacturonase by Dematophora necatrix

Dematophora necatrix, the causal agent of the white root rot disease in plants, produced large amounts of cellulase (Cx) and very small amounts of polygalacturonase (PG). Both tannins (100 mg/l) and phenols (200 mg/l) extracted from roots of plants showing resistance to the disease decreased Cx production in vitro. PG production was affected only by tannin extracts. Exposure of the fungus for 2 days to the tannin (100 mg/l) but not to the phenol (200 mg/l) extracts decreased the subsequent rate of fungal growth in an agar medium free of these compounds.