Abstract

In the rice plant-blast interaction, the incompatible reaction is not dependent only on the cultivar, and also the compatible reaction is not dependent only on the pathogenic race. The reaction depends on the combination of the cultivar and the attacking race. Induced resistance and induced susceptibility have been noted in the interaction. Similar effects in a cultivar were triggered by the fluid of germinating spores in some isolates. Novel glycoproteins, which have potential suppressor activity to induce susceptibility and also to enhance the growth of invasive hyphae, were found in the fluid. These glycoproteins were fractionated by Concanavalin A affinity chromatography and analyzed by 2-dimensional electrophoresis. Both the sugar moiety and the peptide chain were involved in the activity. The other fraction in the fluid not bound to the column had activity to elicit some events associated with the resistant reaction. These glycoproteins had ability to interact with the mannose-binding rice lectin.