Resistance against multiple plant viruses in plants mediated by a double stranded-RNA specific ribonuclease.

Many plant viruses have single-stranded RNAs as their genomes. During the course of replication, genomic RNAs and their complementary template RNAs are likely to form double-stranded (ds) RNA at least transiently. To attack replication intermediates of many plant RNA viruses specifically, we introduced a yeast-derived ds-RNA specific RNase gene called pac 1 into plants. The transformed plants showed a decrease in lesion numbers when they were challenged with tomato mosaic virus, and a delay in the appearance of symptoms when inoculated with cucumber mosaic virus or potato virus Y.