RESISTANCE TO TOBACCO ETCH VIRUS IN CAPSICUM-ANNUUM - INHIBITION OF VIRUS-RNA ACCUMULATION

Resistance to tobacco etch potyvirus (TEV) in Capsicum annuum cv, Demp sey is conferred by the recessive gene et(a), When Dempsey pepper plan ts were inoculated with either of two TEV isolates, virus did not accu mulate in inoculated or noninoculated leaves, In contrast, each TEV is olate replicated to high levels in C. annuum cv, Jupiter, a susceptibl e parent of Dempsey pepper, To determine the basis of the resistance, Dempsey and Jupiter pepper plants were inoculated with a TEV isolate ( TEV-HAT) engineered to express the beta-glucuronidase gene (TEV-GUS), TEV-GUS moved cell-to-cell and systemically in infected Jupiter pepper plants. In contrast, there was no evidence of any single-cell infecti on foci induced by TEV-GUS in Dempsey pepper plants. Northern blot ana lysis of protoplasts inoculated with TEV-HAT RNA indicated that virus RNA did not accumulate in Dempsey pepper protoplasts, whereas TEV-HAT did replicate and accumulate in protoplasts from Jupiter pepper plants . Thus, the resistance to TEV conferred by the et(a) gene is due to in terference with virus RNA accumulation.