The Specificity of Transgene Suppression in Plants by Exogenous dsRNA.

The phenomenon of RNA interference (RNAi) is widely used to develop new approaches for crop improvement and plant protection. Recent investigations show that it is possible to downregulate plant transgenes, as more prone sequences to silencing than endogenous genes, by exogenous application of double-stranded RNAs (dsRNAs) and small interfering RNAs (siRNAs). However, there are scarce data on the specificity of exogenous RNAs. In this study, we explored whether plant transgene suppression is sequence-specific to exogenous dsRNAs and whether similar effects can be caused by exogenous DNAs that are known to be perceived by plants and induce certain epigenetic and biochemical changes. We treated transgenic plants of bearing the neomycin phosphotransferase II () transgene with specific synthetic -dsRNAs and non-specific dsRNAs, encoding enhanced green fluorescent protein (), as well as with DNA molecules mimicking the applied RNAs. None of the -dsRNA doses resulted in a significant decrease in transgene expression in the -transgenic plants, while the specific -dsRNA significantly reduced expression in a dose-dependent manner. Long DNAs mimicking dsRNAs and short DNA oligonucleotides mimicking siRNAs did not exhibit a significant effect on transgene expression. Thus, exogenous -dsRNAs induced a sequence-specific and RNA-specific transgene-suppressing effect, supporting external application of dsRNAs as a promising strategy for plant gene regulation.