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Howard JD, Beghyn M, Dewulf N, De Vos Y, Philips A, Portwood D, Kilby PM, Oliver D, Maddelein W, Brown S, Dickman MJ. Chemically-modified dsRNA induces RNAi effects in insects in vitro and in vivo: A potential new tool for improving RNA-based plant protection. J Biol Chem 2022; 298:102311. [PMID: 35921898 PMCID: PMC9478931 DOI: 10.1016/j.jbc.2022.102311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 07/15/2022] [Accepted: 07/16/2022] [Indexed: 11/28/2022] Open
Abstract
Global agriculture loses over $100 billion of produce annually to crop pests such as insects. Many of these crop pests either are not currently controlled by artificial means or have developed resistance against chemical pesticides. Long dsRNAs are capable of inducing RNAi in insects and are emerging as novel, highly selective alternatives for sustainable insect management strategies. However, there are significant challenges associated with RNAi efficacy in insects. In this study, we synthesized a range of chemically modified long dsRNAs in an approach to improve nuclease resistance and RNAi efficacy in insects. Our results showed that dsRNAs containing phosphorothioate modifications demonstrated increased resistance to southern green stink bug saliva nucleases. Phosphorothioate-modified and 2′-fluoro-modified dsRNA also demonstrated increased resistance to degradation by soil nucleases and increased RNAi efficacy in Drosophila melanogaster cell cultures. In live insects, we found chemically modified long dsRNAs successfully resulted in mortality in both stink bug and corn rootworm. These results provide further mechanistic insight into the dependence of RNAi efficacy on nucleotide modifications in the sense or antisense strand of the dsRNA in insects and demonstrate for the first time that RNAi can successfully be triggered by chemically modified long dsRNAs in insect cells or live insects.
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Affiliation(s)
- John D Howard
- Department of Chemical & Biological Engineering, University of Sheffield, Sheffield, United Kingdom
| | | | | | - Yves De Vos
- Syngenta, Ghent Innovation Center, Ghent, Belgium
| | | | - David Portwood
- Syngenta, Jealott's Hill International Research Centre, Bracknell, United Kingdom
| | - Peter M Kilby
- Syngenta, Jealott's Hill International Research Centre, Bracknell, United Kingdom
| | | | | | - Stephen Brown
- Sheffield RNAi Screening Facility, School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Mark J Dickman
- Department of Chemical & Biological Engineering, University of Sheffield, Sheffield, United Kingdom.
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Sanders M, Lannoo N, Maddelein W, Depicker A, Van Montagu M, Cornelissen M, Jacobs J. The preferred route for the degradation of silencing target RNAs in transgenic plants depends on pre-established silencing conditions. Nucleic Acids Res 2004; 32:3400-9. [PMID: 15220468 PMCID: PMC443538 DOI: 10.1093/nar/gkh662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2004] [Revised: 06/03/2004] [Accepted: 06/03/2004] [Indexed: 11/13/2022] Open
Abstract
RNA silencing can be initiated upon dsRNA accumulation and results in homology-dependent degradation of target RNAs mediated by 21-23 nt small interfering RNAs (siRNAs). These small regulatory RNAs can direct RNA degradation via different routes such as the RdRP/Dicer- and the RNA-induced silencing complex (RISC)-catalysed pathways. The relative contribution of both pathways to degradation of target RNAs is not understood. To gain further insight in the process of target selection and degradation, we analysed production of siRNAs characteristic for Dicer-mediated RNA degradation during silencing of mRNAs and chimeric viral RNAs in protoplasts from plants of a transgenic tobacco silencing model line. We show that small RNA accumulation is limited to silencing target regions during steady-state mRNA silencing. For chimeric viral RNAs, siRNA production appears dependent on pre-established cellular silencing conditions. The observed siRNA accumulation profiles imply that silencing of viral target RNAs in pre-silenced protoplasts occurs mainly via a RISC-mediated pathway, guided by (pre-existing) siRNAs derived from cellular mRNAs. In cells that are not silenced at the time of infection, viral RNA degradation seems to involve Dicer action directly on the viral RNAs. This suggests that the silencing mechanism flexibly deploys different components of the RNA degradation machinery in function of the prevailing silencing status.
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Affiliation(s)
- Matthew Sanders
- Unit of Molecular Signal Transduction in Inflammation, Department for Molecular Biomedical Research, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, Technologiepark 927, B-9052 Gent, Zwijnaarde, Belgium.
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Sanders M, Maddelein W, Depicker A, Van Montagu M, Cornelissen M, Jacobs J. An active role for endogenous beta-1,3-glucanase genes in transgene-mediated co-suppression in tobacco. EMBO J 2002; 21:5824-32. [PMID: 12411500 PMCID: PMC131083 DOI: 10.1093/emboj/cdf586] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2002] [Revised: 09/06/2002] [Accepted: 09/16/2002] [Indexed: 11/14/2022] Open
Abstract
Post-transcriptional gene silencing (PTGS) is characterized by the accumulation of short interfering RNAs that are proposed to mediate sequence-specific degradation of cognate and secondary target mRNAs. In plants, it is unclear to what extent endogenous genes contribute to this process. Here, we address the role of the endogenous target genes in transgene-mediated PTGS of beta-1,3-glucanases in tobacco. We found that mRNA sequences of the endogenous glucanase glb gene with varying degrees of homology to the Nicotiana plumbaginifolia gn1 transgene are targeted by the silencing machinery, although less efficiently than corresponding transgene regions. Importantly, we show that endogene-specific nucleotides in the glb sequence provide specificity to the silencing process. Consistent with this finding, small sense and antisense 21- to 23-nucleotide RNAs homologous to the endogenous glb gene were detected. Combined, these data demonstrate that a co-suppressed endogenous glucan ase gene is involved in signal amplification and selection of homologous targets, and show that endogenous genes can actively participate in PTGS in plants. The findings are introduced as a further sophistication of the post-transciptional silencing model.
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Affiliation(s)
- Matthew Sanders
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent and Bayer Bioscience N.V., J. Plateaustraat 22, B-9000 Ghent, Belgium Present address: Devgen N.V., Technologiepark 9, B-9052 Zwijnaarde, Belgium Corresponding author e-mail:
| | - Wendy Maddelein
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent and Bayer Bioscience N.V., J. Plateaustraat 22, B-9000 Ghent, Belgium Present address: Devgen N.V., Technologiepark 9, B-9052 Zwijnaarde, Belgium Corresponding author e-mail:
| | - Anna Depicker
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent and Bayer Bioscience N.V., J. Plateaustraat 22, B-9000 Ghent, Belgium Present address: Devgen N.V., Technologiepark 9, B-9052 Zwijnaarde, Belgium Corresponding author e-mail:
| | - Marc Van Montagu
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent and Bayer Bioscience N.V., J. Plateaustraat 22, B-9000 Ghent, Belgium Present address: Devgen N.V., Technologiepark 9, B-9052 Zwijnaarde, Belgium Corresponding author e-mail:
| | - Marc Cornelissen
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent and Bayer Bioscience N.V., J. Plateaustraat 22, B-9000 Ghent, Belgium Present address: Devgen N.V., Technologiepark 9, B-9052 Zwijnaarde, Belgium Corresponding author e-mail:
| | - John Jacobs
- Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology (VIB), Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent and Bayer Bioscience N.V., J. Plateaustraat 22, B-9000 Ghent, Belgium Present address: Devgen N.V., Technologiepark 9, B-9052 Zwijnaarde, Belgium Corresponding author e-mail:
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