Replicase-mediated resistance: a novel type of virus resistance in transgenic plants?

Genetically engineered plants expressing either intact or mutant forms of the virus-encoded replicase subunit are resistant to infection by the virus from which the transgene was obtained. In many instances, the resistance is very effective and will be useful in the field. However, some unexpected features of the resistance in these transgenic plants indicate that simple models for the mechanism of replicase-mediated resistance do not apply.