Possible involvement of surface substances on germinated spores of Ceratocystis fimbriata, black rot fungus, in determination of host-parasite specificity.

Abstract

We studied the role of surface substances on germinated spores in host-parasite interaction using rabbit antiserum against the substances from germinated spores of sweet potato strain of Ceratocystis fimbriata, compatible with sweet potato. The antiserum agglutinated the germinated spores of this strain and also decreased ethylene production in sweet potato root tissues infected by this strain, which was used here as an index of pathogenicity. On the other hand, the antiserum showed little effect on ethylene production in the root tissues infected by coffee strain, incompatible with sweet potato. The surface substances from germinated spores of sweet potato strain were fractionated into four fractions with ammonium sulfate; precipitates by 0-20%, 20-40%, and 40-60% saturation of ammonium sulfate and the final supernatant. These fractions were assayed for spore agglutination inhibitory activity, ethylene production stimulative activity and antiserum adsorptive activity. All three activities were localized in the same fraction, that precipitated by 0-20% saturation, suggesting the involvement of the same entity or entities in these activities.