Cell wall polysaccharide-degrading enzymes produced by isolates of Mycocentrospora acerina differing in aggressiveness on carrot.
Cam, B. le, Massiot, P. and Rouxel, F.
Physiological and molecular plant pathology. Vol: 44 Issue: 3 Pages: 187-198
1994
บทคัดย่อ
Plant cell wall polysaccharide-degrading enzymes have been reported to be a determining factor in fungal pathogenesis because of their ability to macerate plant tissue and also to release endogenous elicitors of plant defence responses. Four isolates of Mycocentrospora acerina, a necrotrophic fungus, were characterized for aggressiveness and studied for the production of these enzymes. Induction of polygalacturonase and beta-1,4-glucanase in M. acerina required substrate and was repressed by glucose. When grown in liquid culture with carrot cell walls as a source of carbon, the fungus secreted pectin methylesterase, polygalacturonase, pectate lyase, beta-1,4-glucanase; all activities were positively correlated with isolate aggressiveness. Time-course experiments showed that aggressive isolates produced polygalacturonases and pectin methylesterases more rapidly than hypoaggressive ones, but the patterns of pectin methylesterase and polygalacturonase isozymes were identical for all the tested isolates. The rate at which carrot cell walls were solubilized and depolymerized was also related to isolate aggressiveness, suggesting a strong contribution of cell wall polysaccharide-degrading enzymes in M. acerina aggressiveness. On the other hand, analysis of polygalacturonic acid hydrolysis by isolates indicated that the release of oligogalacturonides was delayed and prolonged