Plants combat infection by gene silencing

Plants with resistance genes can combat viruses by eliciting an incompatible interaction at the site of infection. Resistance can also occur in plants containing transgenes that share homology with an infecting virus, by the silencing of gene expression. Here we describe a natural resistance to the DNA pararetrovirus cauliflower mosaic virus (CaMV), in non-transgenic brassicas, which also involves post-transcriptional gene silencing.