Abstract
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 Arabidopsis thaliana bearing the neomycin phosphotransferase II (NPTII) transgene with specific synthetic NPTII-dsRNAs and non-specific dsRNAs, encoding enhanced green fluorescent protein (EGFP), as well as with DNA molecules mimicking the applied RNAs. None of the EGFP-dsRNA doses resulted in a significant decrease in NPTII transgene expression in the NPTII-transgenic plants, while the specific NPTII-dsRNA significantly reduced NPTII expression in a dose-dependent manner. Long DNAs mimicking dsRNAs and short DNA oligonucleotides mimicking siRNAs did not exhibit a significant effect on NPTII transgene expression. Thus, exogenous NPTII-dsRNAs induced a sequence-specific and RNA-specific transgene-suppressing effect, supporting external application of dsRNAs as a promising strategy for plant gene regulation.
Highlights
Global population growth and the controversy surrounding transgenic plants require the development of new strategies and approaches to improve the nutritional properties of plants and their stress resistance
The major RNA interference (RNAi)-based process of plant protection and crop improvement involved the production of plants expressing double-stranded RNA precursors (dsRNAs) or hairpin RNAs, application of modified plant viruses for virus-induced gene silencing (VIGS), and the host-mediated silencing of pathogen genes for host-induced gene silencing (HIGS) [4,7,8]
Results of the present study showed that exogenous RNAs induce a sequence-specific and RNA-specific transgene-suppressing effect, indicating a significant potential of exogenous RNAs as a promising strategy in plant management
Summary
Global population growth and the controversy surrounding transgenic plants require the development of new strategies and approaches to improve the nutritional properties of plants and their stress resistance. Plant siRNAs are often modified by 20 -O-methylation at 30 ends by HUA ENHANCER 1 (HEN1) to confer stability and prevent degradation by nucleases [5]. These small RNAs are incorporated into the RNA-induced silencing complex (RISC), which cleaves homologous mRNAs or delays their translation [5,6]. The major RNAi-based process of plant protection and crop improvement involved the production of plants expressing dsRNAs or hairpin RNAs (hpRNAs), application of modified plant viruses for virus-induced gene silencing (VIGS), and the host-mediated silencing of pathogen genes for host-induced gene silencing (HIGS) [4,7,8]
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