ANALYSIS OF BLAST DISEASE RESISTANCE INDUCED BY PROBENAZOLE IN RICE

Probenazole (3-allyloxy-1,2-benzisothiazole-1,1-dioxide) induces a resistance reaction in rice plants (Oryza sativa cv. Nipponbare) against infection by the rice blast fungus, Pyricularia oryzae. A cDNA clone of which the mRNAs were enriched by treatment with probenazole was isolated by the differential screening method. The transcript for the clone was abundant in the green leaves, stems and spikelets. The amounts of mRNAs for the small subunit of ribulose 1,5-bisphosphate carboxylase and the light-harvesting chlorophyll a/b-binding protein drastically decreased 48 hr after inoculation, indicating that these house-keeping genes are rapidly repressed during the resistance reaction induced by probenazole. These results suggest that probenazole regulates gene activities of rice plants infected with P. oryzae.