Resistance to Cymbidium Ringspot Tombusvirus Infection in Transgenic Nicotiana benthamiana Plants Expressing a Full-Length Viral Replicase Gene. Luisa Rubino. Dipartimento di Protezione delle Piante, Università degli Studi, and Centro di Studio del CNR sui Virus e le Virosi delle Colture Mediterranee, Bari, Italy. Rossella Lupo, and Marcello Russo. Dipartimento di Protezione delle Piante, Università degli Studi, and Centro di Studio del CNR sui Virus e le Virosi delle Colture Mediterranee, Bari, Italy.. MPMI 6:729-734. Accepted 18 August 1993. Copyright 1993 The American Phytopathological Society.

Nicotiana benthamiana plants were transformed with a full-length replicase gene, corresponding to the first open reading frame of Cymbidium ringspot tombusvirus (CyRSV) RNA. Transgenic plants of one line out of five were highly resistant when challenged with CyRSV virions and immune when inoculated with viral RNA. Resistance was at the cellular level and was not due to inhibition of cell-to-cell spread, as shown experimentally by inoculation and resistance of protoplasts from these transgenic plants.