Virus resistance and gene silencing: killing the messenger

On occassion, virus-derived transgenes in plants can be poorly expressed an d yet provide excellent virus resistance, and transgene constructs designed to supplement the expression of endogenous genes can have the effect of co -suppressing themselves and the endogenous genes. These two phenomena appea r to result from the same poet-transcriptional silencing mechanism, which o perates by targeted-RMA degradation. Recent research into RNA-mediated viru s resistance and co-suppression has provided insights into the interactions between plant Viruses and their hosts, and spawned several models to expla in the phenomenon.