Temporary silencing targeted plant genes with exogenous application of dsRNA

Silencing of plant genes has been a stable technique in plant molecular biology however the two best methods at the moment are either permanently transforming the plant, which results in a genetically modified organism, or transient silencing induced by viral-induced gene silencing (VIGS), which relies on a compatible viral vector. Recent work has shown the capacity of exogenously applied double-stranded RNA (dsRNA) to induce viral resistance in plants, a process that is only possible if the dsRNA is entering the plant cells. To date, there has been little work on showing the capacity of exogenously applied dsRNA to knockdown endogenous plant genes, and no reports on a stable and consistent method to induce temporary target gene silencing using exogenously applied dsRNA. This report details an attempt to develop a model system using the Arabidopsis gene PHYTOENE DESATURASE3 (PDS3) and shows that it is possible to induce target gene knockdown by applying dsRNA to leaf tissue. Unfortunately, this system did not work consistently, only inducing the expected phenotype sporadically throughout the groups, but the PDS3 remained suppressed 7 days after dsRNA application.