Gene Silencing in Plants

Post-transcriptional gene silencing (PTGS) is a sequence-specific RNA down-regulation mechanism that targets the trigger RNA molecules as well as the RNA molecules that share a sequence homology with the trigger. Since its first discovery in plants almost two decades ago, PTGS has now been characterized in diverse eukaryotic organisms including fungi, worms, flies, mammals and possibly in bacteria. A common characteristic feature of these processes is the sequence-specific RNA degradation called RNA interference (RNAi). It is well documented that genes controlling RNAi in fungi and animals often show high levels of sequence homology with genes controlling PTGS in plants suggesting that these processes are mechanistically linked and might coalesce to a common ancestral origin. We recently discovered a novel PTGS based silencing called Direct Repeat Induced Gene Silencing (DRIGS). We constructed and tested a series of vectors specifically designed for silencing of random or targeted sequences in plants creating mutants. Plant mutagenesis is a key element of gene function studies. Phenotype-driven approaches using DRIGS represent a potentially efficient route for generation of large number of transformants that can be screened for novel phenotypes. DRIGS vector induced silencing can be used to associate gene sequences with function. DRIGS can also be used as a silencing based tool for plant functional genomics.