Fast forward genetics based on virus-induced gene silencing.

Gene expression in plants can be suppressed in a sequence-specific manner by infection with virus vectors carrying fragments of host genes. Recent developments have revealed that the mechanism of this gene silencing is based on an RNA-mediated defence against viruses. It has also emerged that a related mechanism is involved in the post-transcriptional silencing that accounts for between line variation in transgene expression and cosuppresion of transgenes and endogenous genes. The technology of virus-induced gene silencing is being refined and adapted as a high throughput procedure for functional genomics in plants.