1
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Zhao X, Liu Z, Liu Y, Lu M, Xu J, Wu F, Jin W. Development and application of an RNA nanostructure to induce transient RNAi in difficult transgenic plants. Biotechnol J 2024; 19:e2400024. [PMID: 38797726 DOI: 10.1002/biot.202400024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/29/2024]
Abstract
The development of RNA interference (RNAi) is crucial for studying plant gene function. Its use, is limited to a few plants with well-established transgenic techniques. Spray-induced gene silencing (SIGS) introduces exogenous double-stranded RNA (dsRNA) into plants by spraying, injection, or irrigation, triggering the RNAi pathway to instantly silence target genes. As is a transient RNAi technology that does not rely on transgenic methods, SIGS has significant potential for studying gene function in plants lacking advanced transgenic technology. In this study, to enhance their stability and delivery efficiency, siRNAs were used as structural motifs to construct RNA nanoparticles (NPs) of four shapes: triangle, square, pentagon, and hexagon. These NPs, when synthesized by Escherichia coli, showed that triangular and square shapes accumulated more efficiently than pentagon and hexagon shapes. Bioassays revealed that RNA squares had the highest RNAi efficiency, followed by RNA triangles, with GFP-dsRNA showing the lowest efficiency at 4 and 7 days post-spray. We further explored the use of RNA squares in inducing transient RNAi in plants that are difficult to transform genetically. The results indicated that Panax notoginseng-derived MYB2 (PnMYB2) and Camellia oleifera-derived GUT (CoGUT) were significantly suppressed in P. notoginseng and C. oleifera, respectively, following the application of PnMYB2- and CoGUT-specific RNA squares. These findings suggest that RNA squares are highly effective in SIGS and can be utilized for gene function research in plants.
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Affiliation(s)
- Xiayang Zhao
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Zhekai Liu
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
- Zhejiang Sci-Tech University Shaoxing Academy of Biomedicine Co. Ltd., Shaoxing, Zhejiang, China
| | - Yiqing Liu
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
- Zhejiang Sci-Tech University Shaoxing Academy of Biomedicine Co. Ltd., Shaoxing, Zhejiang, China
| | - Mingdong Lu
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
- Zhejiang Sci-Tech University Shaoxing Academy of Biomedicine Co. Ltd., Shaoxing, Zhejiang, China
| | - Jinfeng Xu
- Zhejiang Sci-Tech University Shaoxing Academy of Biomedicine Co. Ltd., Shaoxing, Zhejiang, China
| | - Fangli Wu
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
| | - Weibo Jin
- Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, China
- Zhejiang Sci-Tech University Shaoxing Academy of Biomedicine Co. Ltd., Shaoxing, Zhejiang, China
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2
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Wang GD, Lin CC, Chen TC. Development of Attenuated Viruses for Effective Protection against Pepper Veinal Mottle Virus in Tomato Crops. Viruses 2024; 16:687. [PMID: 38793569 PMCID: PMC11125906 DOI: 10.3390/v16050687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 04/17/2024] [Accepted: 04/23/2024] [Indexed: 05/26/2024] Open
Abstract
Tomato (Solanum lycopersicum) is the most important vegetable and fruit crop in the family Solanaceae worldwide. Numerous pests and pathogens, especially viruses, severely affect tomato production, causing immeasurable market losses. In Taiwan, the cultivation of tomato crops is mainly threatened by insect-borne viruses, among which pepper veinal mottle virus (PVMV) is one of the most prevalent. PVMV is a member of the genus Potyvirus of the family Potyviridae and is non-persistently transmitted by aphids. Its infection significantly reduces tomato fruit yield and quality. So far, no PVMV-resistant tomato lines are available. In this study, we performed nitrite-induced mutagenesis of the PVMV tomato isolate Tn to generate attenuated PVMV mutants. PVMV Tn causes necrotic lesions in Chenopodium quinoa leaves and severe mosaic and wilting in Nicotiana benthamiana plants. After nitrite treatment, three attenuated PVMV mutants, m4-8, m10-1, and m10-11, were selected while inducing milder responses to C. quinoa and N. benthamiana with lower accumulation in tomato plants. In greenhouse tests, the three mutants showed different degrees of cross-protection against wild-type PVMV Tn. m4-8 showed the highest protective efficacy against PVMV Tn in N. benthamiana and tomato plants, 100% and 97.9%, respectively. A whole-genome sequence comparison of PVMV Tn and m4-8 revealed that 20 nucleotide substitutions occurred in the m4-8 genome, resulting in 18 amino acid changes. Our results suggest that m4-8 has excellent potential to protect tomato crops from PVMV. The application of m4-8 in protecting other Solanaceae crops, such as peppers, will be studied in the future.
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Affiliation(s)
| | | | - Tsung-Chi Chen
- Department of Medical Laboratory Science and Biotechnology, Asia University, Wufeng, Taichung 41354, Taiwan; (G.-D.W.); (C.-C.L.)
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3
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Frascati F, Rotunno S, Accotto GP, Noris E, Vaira AM, Miozzi L. Exogenous Application of dsRNA for Protection against Tomato Leaf Curl New Delhi Virus. Viruses 2024; 16:436. [PMID: 38543801 PMCID: PMC10974794 DOI: 10.3390/v16030436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/26/2024] [Accepted: 03/07/2024] [Indexed: 05/23/2024] Open
Abstract
Tomato leaf curl New Delhi virus (ToLCNDV) is an emerging plant pathogen, fast spreading in Asian and Mediterranean regions, and is considered the most harmful geminivirus of cucurbits in the Mediterranean. ToLCNDV infects several plant and crop species from a range of families, including Solanaceae, Cucurbitaceae, Fabaceae, Malvaceae and Euphorbiaceae. Up to now, protection from ToLCNDV infection has been achieved mainly by RNAi-mediated transgenic resistance, and non-transgenic fast-developing approaches are an urgent need. Plant protection by the delivery of dsRNAs homologous to a pathogen target sequence is an RNA interference-based biotechnological approach that avoids cultivating transgenic plants and has been already shown effective against RNA viruses and viroids. However, the efficacy of this approach against DNA viruses, particularly Geminiviridae family, is still under study. Here, the protection induced by exogenous application of a chimeric dsRNA targeting all the coding regions of the ToLCNDV DNA-A was evaluated in zucchini, an important crop strongly affected by this virus. A reduction in the number of infected plants and a delay in symptoms appearance, associated with a tendency of reduction in the viral titer, was observed in the plants treated with the chimeric dsRNA, indicating that the treatment is effective against geminiviruses but requires further optimization. Limits of RNAi-based vaccinations against geminiviruses and possible causes are discussed.
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Affiliation(s)
| | | | | | | | - Anna Maria Vaira
- Institute for Sustainable Plant Protection, National Research Council, Strada delle Cacce 73, 10135 Torino, Italy (S.R.); (G.P.A.); (E.N.)
| | - Laura Miozzi
- Institute for Sustainable Plant Protection, National Research Council, Strada delle Cacce 73, 10135 Torino, Italy (S.R.); (G.P.A.); (E.N.)
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4
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Othman SMIS, Mustaffa AF, Mohd Zahid NII, Che-Othman MH, Samad AFA, Goh HH, Ismail I. Harnessing the potential of non-coding RNA: An insight into its mechanism and interaction in plant biotic stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108387. [PMID: 38266565 DOI: 10.1016/j.plaphy.2024.108387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 01/02/2024] [Accepted: 01/17/2024] [Indexed: 01/26/2024]
Abstract
Plants have developed diverse physical and chemical defence mechanisms to ensure their continued growth and well-being in challenging environments. Plants also have evolved intricate molecular mechanisms to regulate their responses to biotic stress. Non-coding RNA (ncRNA) plays a crucial role in this process that affects the expression or suppression of target transcripts. While there have been numerous reviews on the role of molecules in plant biotic stress, few of them specifically focus on how plant ncRNAs enhance resistance through various mechanisms against different pathogens. In this context, we explored the role of ncRNA in exhibiting responses to biotic stress endogenously as well as cross-kingdom regulation of transcript expression. Furthermore, we address the interplay between ncRNAs, which can act as suppressors, precursors, or regulators of other ncRNAs. We also delve into the regulation of ncRNAs in response to attacks from different organisms, such as bacteria, viruses, fungi, nematodes, oomycetes, and insects. Interestingly, we observed that diverse microorganisms interact with distinct ncRNAs. This intricacy leads us to conclude that each ncRNA serves a specific function in response to individual biotic stimuli. This deeper understanding of the molecular mechanisms involving ncRNAs in response to biotic stresses enhances our knowledge and provides valuable insights for future research in the field of ncRNA, ultimately leading to improvements in plant traits.
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Affiliation(s)
- Syed Muhammad Iqbal Syed Othman
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - Arif Faisal Mustaffa
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - Nur Irdina Izzatie Mohd Zahid
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - M Hafiz Che-Othman
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - Abdul Fatah A Samad
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru, 81310, Johor, Malaysia
| | - Hoe-Han Goh
- Institute of Systems Biology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia
| | - Ismanizan Ismail
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia; Institute of Systems Biology, Universiti Kebangsaan Malaysia (UKM), Bangi, 43600, Selangor, Malaysia.
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5
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Samarskaya VO, Spechenkova N, Ilina I, Suprunova TP, Kalinina NO, Love AJ, Taliansky ME. A Non-Canonical Pathway Induced by Externally Applied Virus-Specific dsRNA in Potato Plants. Int J Mol Sci 2023; 24:15769. [PMID: 37958754 PMCID: PMC10650801 DOI: 10.3390/ijms242115769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/21/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
The external application of double-stranded RNA (dsRNA) has recently been developed as a non-transgenic approach for crop protection against pests and pathogens. This novel and emerging approach has come to prominence due to its safety and environmental benefits. It is generally assumed that the mechanism of dsRNA-mediated antivirus RNA silencing is similar to that of natural RNA interference (RNAi)-based defence against RNA-containing viruses. There is, however, no direct evidence to support this idea. Here, we provide data on the high-throughput sequencing (HTS) analysis of small non-coding RNAs (sRNA) as hallmarks of RNAi induced by infection with the RNA-containing potato virus Y (PVY) and also by exogenous application of dsRNA which corresponds to a fragment of the PVY genome. Intriguingly, in contrast to PVY-induced production of discrete 21 and 22 nt sRNA species, the externally administered PVY dsRNA fragment led to generation of a non-canonical pool of sRNAs, which were present as ladders of ~18-30 nt in length; suggestive of an unexpected sRNA biogenesis pathway. Interestingly, these non-canonical sRNAs are unable to move systemically and also do not induce transitive amplification. These findings may have significant implications for further developments in dsRNA-mediated crop protection.
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Affiliation(s)
- Viktoriya O. Samarskaya
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (V.O.S.); (N.S.); (I.I.); (N.O.K.)
| | - Nadezhda Spechenkova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (V.O.S.); (N.S.); (I.I.); (N.O.K.)
| | - Irina Ilina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (V.O.S.); (N.S.); (I.I.); (N.O.K.)
| | | | - Natalia O. Kalinina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (V.O.S.); (N.S.); (I.I.); (N.O.K.)
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Andrew J. Love
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK;
| | - Michael E. Taliansky
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (V.O.S.); (N.S.); (I.I.); (N.O.K.)
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK;
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6
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Kamesh Krishnamoorthy K, Malathi VG, Renukadevi P, Kumar SM, Raveendran M, Sudha M, Manivannan N, Karthikeyan G. Exogenous delivery of dsRNA for management of mungbean yellow mosaic virus on blackgram. PLANTA 2023; 258:94. [PMID: 37804329 DOI: 10.1007/s00425-023-04253-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 09/23/2023] [Indexed: 10/09/2023]
Abstract
MAIN CONCLUSION Exogenous application of dsRNA molecules targeting MYMV genes offers a promising approach to effectively mitigate yellow mosaic disease in blackgram, demonstrating potential for sustainable plant viral disease management. The exogenous application of double-stranded RNA (dsRNA) molecules to control plant viral diseases is gaining traction due to its advantages over conventional methods, such as target specificity, non-polluting nature, and absence of residue formation. Furthermore, this approach does not involve genome modification. In this study, dsRNA molecules targeting the coat protein gene (dsCP) and replication initiator protein gene (dsRep) of mungbean yellow mosaic virus (MYMV) were synthesised using an in vitro transcription method. To evaluate the effectiveness of dsRNA treatment, blackgram plants exhibiting MYMV symptoms at the first trifoliate stage were subjected to exogenous application of dsRNA. Second, third, and fourth trifoliate leaves, which emerged at 7, 15, and 21 days after dsRNA application, respectively, were monitored for MYMV symptoms. Remarkably, a significant reduction in yellow mosaic disease (YMD) symptoms was observed in the newly emerged trifoliate leaves of MYMV-infected blackgram plants after treatment with dsRNA targeting both gene regions. This reduction was evident as a decrease in the intensity of yellow mosaic coverage on the leaf lamina compared to control. dsCP effectively reduced the MYMV titre in the treated plants for up to 15 days. However, dsRep demonstrated greater efficiency in conferring resistance to MYMV at 15 days post-application. These findings were supported by quantitative real-time PCR analysis, where the observed Ct values for DNA extracted from dsRep-treated plants were significantly higher compared to the Ct values of DNA from dsCP-treated plants at 15 days post-application. Similarly, higher viral copy numbers were observed in dsCP-treated plants 15 days after dsRNA treatment, in contrast to plants treated with dsRep.
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Affiliation(s)
- K Kamesh Krishnamoorthy
- Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - V G Malathi
- Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - P Renukadevi
- Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - S Mohan Kumar
- Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - M Raveendran
- Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - M Sudha
- Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - N Manivannan
- National Pulses Research Centre, Tamil Nadu Agricultural University, Vamban, 622303, India
| | - G Karthikeyan
- Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, 641003, India.
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7
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Koloniuk I, Matyášová A, Brázdová S, Veselá J, Přibylová J, Várallyay E, Fránová J. Analysis of Virus-Derived siRNAs in Strawberry Plants Co-Infected with Multiple Viruses and Their Genotypes. PLANTS (BASEL, SWITZERLAND) 2023; 12:2564. [PMID: 37447124 DOI: 10.3390/plants12132564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023]
Abstract
Plants can be infected with multiple viruses. High-throughput sequencing tools have enabled numerous discoveries of multi-strain infections, when more than one viral strain or divergent genomic variant infects a single plant. Here, we investigated small interfering RNAs (siRNAs) in a single strawberry plant co-infected with several strains of strawberry mottle virus (SMoV), strawberry crinkle virus (SCV) and strawberry virus 1 (StrV-1). A range of plants infected with subsets of the initial viral species and strains that were obtained by aphid-mediated transmission were also evaluated. Using high-throughput sequencing, we characterized the small RNA fractions associated with different genotypes of these three viruses and determined small RNA hotspot regions in viral genomes. A comparison of virus-specific siRNA (vsiRNA) abundance with relative viral concentrations did not reveal any consistent agreement. Strawberry mottle virus strains exhibiting considerable variations in concentrations were found to be associated with comparable quantities of vsiRNAs. Additionally, by estimating the specificity of siRNAs to different viral strains, we observed that a substantial pool of vsiRNAs could target all SMoV strains, while strain-specific vsiRNAs predominantly targeted rhabdoviruses, SCV and StrV-1. This highlights the intricate nature and potential interference of the antiviral response within a single infected plant when multiple viruses are present.
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Affiliation(s)
- Igor Koloniuk
- Institute of Plant Molecular Biology, Department of Plant Virology, Biology Centre CAS, 370 05 Ceske Budejovice, Czech Republic
| | - Alena Matyášová
- Institute of Plant Molecular Biology, Department of Plant Virology, Biology Centre CAS, 370 05 Ceske Budejovice, Czech Republic
| | - Sára Brázdová
- Institute of Plant Molecular Biology, Department of Plant Virology, Biology Centre CAS, 370 05 Ceske Budejovice, Czech Republic
- Faculty of Agriculture, University of South Bohemia, 370 05 Ceske Budejovice, Czech Republic
| | - Jana Veselá
- Institute of Plant Molecular Biology, Department of Plant Virology, Biology Centre CAS, 370 05 Ceske Budejovice, Czech Republic
| | - Jaroslava Přibylová
- Institute of Plant Molecular Biology, Department of Plant Virology, Biology Centre CAS, 370 05 Ceske Budejovice, Czech Republic
| | - Eva Várallyay
- Genomics Research Group, Institute of Plant Protection, Department of Plant Pathology, Hungarian University of Agriculture and Life Sciences, Szent-Gyorgyi Albert Street 4, 2100 Gödöllő, Hungary
| | - Jana Fránová
- Institute of Plant Molecular Biology, Department of Plant Virology, Biology Centre CAS, 370 05 Ceske Budejovice, Czech Republic
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8
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Xu X, Yu T, Zhang D, Song H, Huang K, Wang Y, Shen L, Li Y, Wang F, Zhang S, Jiao Y, Yang J. Evaluation of the anti-viral efficacy of three different dsRNA nanoparticles against potato virus Y using various delivery methods. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 255:114775. [PMID: 36933482 DOI: 10.1016/j.ecoenv.2023.114775] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 03/10/2023] [Accepted: 03/12/2023] [Indexed: 06/18/2023]
Abstract
Nanoparticles (NPs) derived from RNA interference (RNAi) are considered a potentially revolutionary technique in the field of plant protection in the future. However, the application of NPs in RNAi is hindered by the conflict between the high cost of RNA production and the large quantity of materials required for field application. This study aimed to evaluate the antiviral efficacy of commercially available nanomaterials, such as chitosan quaternary ammonium salt (CQAS), amine functionalized silica nano powder (ASNP), and carbon quantum dots (CQD), that carried double-stranded RNA (dsRNA) via various delivery methods, including infiltration, spraying, and root soaking. ASNP-dsRNA NPs are recommended for root soaking, which is considered the most effective method of antiviral compound application. The most effective antiviral compound tested was CQAS-dsRNA NPs delivered by root soaking. Using fluorescence, FITC-CQAS-dsCP-Cy3, and CQD-dsCP-Cy3 NPs demonstrated the uptake and transport pathways of dsRNA NPs in plants when applied to plants in different modes. The duration of protection with NPs applied in various modes was then compared, providing references for evaluating the retention period of various types of NPs. All three types of NPs effectively silenced genes in plants and afforded at least 14 days of protection against viral infection. Particularly, CQD-dsRNA NPs could protect systemic leaves for 21 days following spraying.
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Affiliation(s)
- Xiang Xu
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Tingting Yu
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Agriculture and Forestry University, Fuzhou 350000, Fujian, China
| | - Daoshun Zhang
- Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou 434025, Hubei, China
| | - Hongping Song
- Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou 434025, Hubei, China
| | - Kun Huang
- Honghe City Company of Yunnan Province Tobacco Company, Mile 652300, Yunnan, China
| | - Yong Wang
- Liangshan State Company of Sichuan Province Tobacco Company, Xichang 615000, Sichuan, China
| | - Lili Shen
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Ying Li
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Fenglong Wang
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Songbai Zhang
- Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou 434025, Hubei, China
| | - Yubing Jiao
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China.
| | - Jinguang Yang
- Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China.
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9
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Chen D, Yan R, Xu Z, Qian J, Yu Y, Zhu S, Wu H, Zhu G, Chen M. Silencing of dre4 Contributes to Mortality of Phyllotreta striolata. INSECTS 2022; 13:insects13111072. [PMID: 36421975 PMCID: PMC9696999 DOI: 10.3390/insects13111072] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/14/2022] [Accepted: 11/18/2022] [Indexed: 06/01/2023]
Abstract
The striped flea beetle, Phyllotreta striolata, is one of the most destructive pests of Cruciferae crops worldwide. RNA interference (RNAi) is a promising alternative strategy for pest biological control, which overcomes the weakness of synthetic insecticides, such as pest resistance, food safety problems and toxicity to non-target insects. The homolog of Spt16/FACT, dre4 plays a critical role in the process of gene transcription, DNA repair, and DNA replication; however, the effects of dre4 silencing in P. striolata remain elusive. In this study, we cloned and characterized the full-length dre4 from P. striolata and silenced Psdre4 through microinjection and oral delivery; it was found that the silencing of dre4 contributed to the high mortality of P. striolata in both bioassays. Moreover, 1166 differentially regulated genes were identified after Psdre4 interference by RNA-seq analysis, which might have been responsible for the lethality. The GO analysis indicated that the differentially regulated genes were classified into three GO functional categories, including biological process, cellular component, and molecular function. The KEGG analysis revealed that these differentially regulated genes are related to apoptosis, autophagy, steroid hormone biosynthesis, cytochrome P450 and other signaling pathways. Our results suggest that Psdre4 is a fatal RNAi target and has significant potential for the development of RNA pesticides for P. striolata management.
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Affiliation(s)
- Dongping Chen
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou 311300, China
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310030, China
| | - Ru Yan
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310030, China
| | - Zhanyi Xu
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310030, China
| | - Jiali Qian
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310030, China
| | - Yinfang Yu
- Research and Development Center, NeoAgro Co., Ltd., Hangzhou 310022, China
| | - Shunshun Zhu
- Research and Development Center, NeoAgro Co., Ltd., Hangzhou 310022, China
| | - Huiming Wu
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou 311300, China
| | - Guonian Zhu
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou 310030, China
| | - Mengli Chen
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou 311300, China
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10
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Voloudakis AE, Kaldis A, Patil BL. RNA-Based Vaccination of Plants for Control of Viruses. Annu Rev Virol 2022; 9:521-548. [PMID: 36173698 DOI: 10.1146/annurev-virology-091919-073708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Plant viruses cause nearly half of the emerging plant diseases worldwide, contributing to 10-15% of crop yield losses. Control of plant viral diseases is mainly accomplished by extensive chemical applications targeting the vectors (i.e., insects, nematodes, fungi) transmitting these viruses. However, these chemicals have a significant negative effect on human health and the environment. RNA interference is an endogenous, cellular, sequence-specific RNA degradation mechanism in eukaryotes induced by double-stranded RNA molecules that has been exploited as an antiviral strategy through transgenesis. Because genetically modified crop plants are not accepted for cultivation in several countries globally, there is an urgent demand for alternative strategies. This has boosted research on exogenous application of the RNA-based biopesticides that are shown to exhibit significant protective effect against viral infections. Such environment-friendly and efficacious antiviral agents for crop protection will contribute to global food security, without adverse effects on human health.
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Affiliation(s)
- Andreas E Voloudakis
- Laboratory of Plant Breeding and Biometry, Department of Crop Science, Agricultural University of Athens, Athens, Greece;
| | - Athanasios Kaldis
- Laboratory of Plant Breeding and Biometry, Department of Crop Science, Agricultural University of Athens, Athens, Greece;
| | - Basavaprabhu L Patil
- Division of Basic Sciences, ICAR-Indian Institute of Horticultural Research, Bengaluru, Karnataka State, India
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11
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Samarfard S, Ghorbani A, Karbanowicz TP, Lim ZX, Saedi M, Fariborzi N, McTaggart AR, Izadpanah K. Regulatory non-coding RNA: The core defense mechanism against plant pathogens. J Biotechnol 2022; 359:82-94. [PMID: 36174794 DOI: 10.1016/j.jbiotec.2022.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 09/18/2022] [Accepted: 09/21/2022] [Indexed: 12/13/2022]
Abstract
Plant pathogens damage crops and threaten global food security. Plants have evolved complex defense networks against pathogens, using crosstalk among various signaling pathways. Key regulators conferring plant immunity through signaling pathways include protein-coding genes and non-coding RNAs (ncRNAs). The discovery of ncRNAs in plant transcriptomes was first considered "transcriptional noise". Recent reviews have highlighted the importance of non-coding RNAs. However, understanding interactions among different types of noncoding RNAs requires additional research. This review attempts to consider how long-ncRNAs, small-ncRNAs and circular RNAs interact in response to pathogenic diseases within different plant species. Developments within genomics and bioinformatics could lead to the further discovery of plant ncRNAs, knowledge of their biological roles, as well as an understanding of their importance in exploiting the recent molecular-based technologies for crop protection.
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Affiliation(s)
- Samira Samarfard
- Department of Primary Industries and Regional Development, DPIRD Diagnostic Laboratory Services, South Perth, WA, Australia
| | - Abozar Ghorbani
- Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute (NSTRI), Karaj, the Islamic Republic of Iran.
| | | | - Zhi Xian Lim
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Mahshid Saedi
- Department of Plant Protection, Faculty of Agriculture, University of Kurdistan, Sanandaj, the Islamic Republic of Iran
| | - Niloofar Fariborzi
- Department of Medical Entomology and Vector Control, School of Health, Shiraz University of Medical Sciences, Shiraz, the Islamic Republic of Iran
| | - Alistair R McTaggart
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Ecosciences Precinct, Dutton Park, QLD 4102, Australia
| | - Keramatollah Izadpanah
- Plant Virology Research Center, College of Agriculture, Shiraz University, Shiraz, the Islamic Republic of Iran
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12
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Spatial Distribution and Retention in Loblolly Pine Seedlings of Exogenous dsRNAs Applied through Roots. Int J Mol Sci 2022; 23:ijms23169167. [PMID: 36012434 PMCID: PMC9409306 DOI: 10.3390/ijms23169167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 08/05/2022] [Accepted: 08/11/2022] [Indexed: 11/24/2022] Open
Abstract
Exogenously applied double-stranded RNA (dsRNA) can induce potent host specific gene knockdown and mortality in insects. The deployment of RNA-interference (RNAi) technologies for pest suppression is gaining traction in both agriculture and horticulture, but its implementation in forest systems is lagging. While numerous forest pests have demonstrated susceptibility to RNAi mediated gene silencing, including the southern pine beetle (SPB), Dendroctonus frontalis, multiple barriers stand between laboratory screening and real-world deployment. One such barrier is dsRNA delivery. One possible delivery method is through host plants, but an understanding of exogenous dsRNA movement through plant tissues is essential. Therefore, we sought to understand the translocation and persistence of dsRNAs designed for SPB throughout woody plant tissues after hydroponic exposure. Loblolly pine, Pinus taeda, seedlings were exposed to dsRNAs as a root soak, followed by destructive sampling. Total RNA was extracted from different tissue types including root, stem, crown, needle, and meristem, after which gel electrophoresis confirmed the recovery of the exogenous dsRNAs, which were further verified using Sanger sequencing. Both techniques confirmed the presence of the exogenously applied target dsRNAs in each tissue type after 1, 3, 5, and 7 d of dsRNA exposure. These findings suggest that root drench applications of exogenous dsRNAs could provide a viable delivery route for RNAi technology designed to combat tree feeding pests.
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13
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Impact of Exogenous Application of Potato Virus Y-Specific dsRNA on RNA Interference, Pattern-Triggered Immunity and Poly(ADP-ribose) Metabolism. Int J Mol Sci 2022; 23:ijms23147915. [PMID: 35887257 PMCID: PMC9317112 DOI: 10.3390/ijms23147915] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/13/2022] [Accepted: 07/15/2022] [Indexed: 02/06/2023] Open
Abstract
In this work we developed and exploited a spray-induced gene silencing (SIGS)-based approach to deliver double-stranded RNA (dsRNA), which was found to protect potato against potato virus Y (PVY) infection. Given that dsRNA can act as a defence-inducing signal that can trigger sequence-specific RNA interference (RNAi) and non-specific pattern-triggered immunity (PTI), we suspected that these two pathways may be invoked via exogeneous application of dsRNA, which may account for the alterations in PVY susceptibility in dsRNA-treated potato plants. Therefore, we tested the impact of exogenously applied PVY-derived dsRNA on both these layers of defence (RNAi and PTI) and explored its effect on accumulation of a homologous virus (PVY) and an unrelated virus (potato virus X, PVX). Here, we show that application of PVY dsRNA in potato plants induced accumulation of both small interfering RNAs (siRNAs), a hallmark of RNAi, and some PTI-related gene transcripts such as WRKY29 (WRKY transcription factor 29; molecular marker of PTI), RbohD (respiratory burst oxidase homolog D), EDS5 (enhanced disease susceptibility 5), SERK3 (somatic embryogenesis receptor kinase 3) encoding brassinosteroid-insensitive 1-associated receptor kinase 1 (BAK1), and PR-1b (pathogenesis-related gene 1b). With respect to virus infections, PVY dsRNA suppressed only PVY replication but did not exhibit any effect on PVX infection in spite of the induction of PTI-like effects in the presence of PVX. Given that RNAi-mediated antiviral immunity acts as the major virus resistance mechanism in plants, it can be suggested that dsRNA-based PTI alone may not be strong enough to suppress virus infection. In addition to RNAi- and PTI-inducing activities, we also showed that PVY-specific dsRNA is able to upregulate production of a key enzyme involved in poly(ADP-ribose) metabolism, namely poly(ADP-ribose) glycohydrolase (PARG), which is regarded as a positive regulator of biotic stress responses. These findings offer insights for future development of innovative approaches which could integrate dsRNA-induced RNAi, PTI and modulation of poly(ADP-ribose) metabolism in a co-ordinated manner, to ensure a high level of crop protection.
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14
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Touzdjian Pinheiro Kohlrausch Távora F, de Assis dos Santos Diniz F, de Moraes Rêgo-Machado C, Chagas Freitas N, Barbosa Monteiro Arraes F, Chumbinho de Andrade E, Furtado LL, Osiro KO, Lima de Sousa N, Cardoso TB, Márcia Mertz Henning L, Abrão de Oliveira Molinari P, Feingold SE, Hunter WB, Fátima Grossi de Sá M, Kobayashi AK, Lima Nepomuceno A, Santiago TR, Correa Molinari HB. CRISPR/Cas- and Topical RNAi-Based Technologies for Crop Management and Improvement: Reviewing the Risk Assessment and Challenges Towards a More Sustainable Agriculture. Front Bioeng Biotechnol 2022; 10:913728. [PMID: 35837551 PMCID: PMC9274005 DOI: 10.3389/fbioe.2022.913728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated gene (Cas) system and RNA interference (RNAi)-based non-transgenic approaches are powerful technologies capable of revolutionizing plant research and breeding. In recent years, the use of these modern technologies has been explored in various sectors of agriculture, introducing or improving important agronomic traits in plant crops, such as increased yield, nutritional quality, abiotic- and, mostly, biotic-stress resistance. However, the limitations of each technique, public perception, and regulatory aspects are hindering its wide adoption for the development of new crop varieties or products. In an attempt to reverse these mishaps, scientists have been researching alternatives to increase the specificity, uptake, and stability of the CRISPR and RNAi system components in the target organism, as well as to reduce the chance of toxicity in nontarget organisms to minimize environmental risk, health problems, and regulatory issues. In this review, we discuss several aspects related to risk assessment, toxicity, and advances in the use of CRISPR/Cas and topical RNAi-based technologies in crop management and breeding. The present study also highlights the advantages and possible drawbacks of each technology, provides a brief overview of how to circumvent the off-target occurrence, the strategies to increase on-target specificity, the harm/benefits of association with nanotechnology, the public perception of the available techniques, worldwide regulatory frameworks regarding topical RNAi and CRISPR technologies, and, lastly, presents successful case studies of biotechnological solutions derived from both technologies, raising potential challenges to reach the market and being social and environmentally safe.
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Affiliation(s)
| | | | | | | | | | | | | | - Karen Ofuji Osiro
- Department of Phytopathology, University of Brasília, Brasília, Brazil
- Embrapa Agroenergy, Brasília, Brazil
| | | | | | | | | | | | - Wayne B. Hunter
- USDA-ARS, U.S. Horticultural Research Laboratory, Fort Pierce, FL, United States
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15
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Delgado-Martín J, Ruiz L, Janssen D, Velasco L. Exogenous Application of dsRNA for the Control of Viruses in Cucurbits. FRONTIERS IN PLANT SCIENCE 2022; 13:895953. [PMID: 35832223 PMCID: PMC9272007 DOI: 10.3389/fpls.2022.895953] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
The recurrent emergence of viral diseases in intensive horticultural crops requires alternative control strategies. The topical application of double-stranded RNA (dsRNA) molecules homologous to pathogens has been proposed as a tool for virus control in plants. These dsRNAs induce the silencing mechanism, the RNA interference (RNAi), that degrades homologous dsRNAs. Cucumber green mottle mosaic virus (CGMMV) represents a serious threat to cucurbit crops. Since genetic resistance to the virus is not yet available in commercial varieties, we aimed to control this virus by RNAi. For this purpose, we obtained constructions both for expressing dsRNA in bacteria to treat cucumber plants by topical application and for agroinoculation in experiments done in the growth chamber. Besides, greenhouse tests were performed in spring and in summer when plants were challenged with the virus, and differences in several parameters were investigated, including the severity of symptoms, dry weight, total height, virus accumulation, and virus-derived small interfering RNAs (vsiRNAs). Spraying of plants with dsRNA reduced significatively CGMMV symptoms in the plants in growth chamber tests. Agroinfiltration experiments done under identical conditions were also effective in limiting the progress of CGMMV disease. In the greenhouse assay performed in spring, symptoms were significantly reduced in dsRNA-sprayed plants, and the development of the plants improved with respect to non-treated plants. Virus titers and vsiRNAs were clearly reduced in dsRNA-treated plants. The effect of protection of the dsRNA was less evident in the greenhouse assay carried out in the summer. Besides, we investigated the mobility of long (ds)RNA derived from spraying or agroinfiltrated dsRNA and found that it could be detected in local, close distal, and far distal points from the site of application. VsiRNAs were also detected in local and distal points and the differences in accumulation were compared. In parallel, we investigated the capacity of dsRNAs derived from genes of tomato leaf curl New Delhi virus (ToLCNDV), another economically important virus in cucurbits, to limit the disease in zucchini, both by agroinfiltration or by direct spraying, but found no protective effect. In view of the results, the topical application of dsRNAs is postulated as a promising strategy for CGMMV control in the cucumber.
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Affiliation(s)
- Josemaría Delgado-Martín
- Instituto Andaluz de Investigación y Formación Agraria (IFAPA) Centro de Málaga, Málaga, Spain
- Universidad de Málaga, Málaga, Spain
| | - Leticia Ruiz
- Instituto Andaluz de Investigación y Formación Agraria (IFAPA) Centro La Mojonera, Almería, Spain
| | - Dirk Janssen
- Instituto Andaluz de Investigación y Formación Agraria (IFAPA) Centro La Mojonera, Almería, Spain
| | - Leonardo Velasco
- Instituto Andaluz de Investigación y Formación Agraria (IFAPA) Centro de Málaga, Málaga, Spain
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16
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RNAi as a Foliar Spray: Efficiency and Challenges to Field Applications. Int J Mol Sci 2022; 23:ijms23126639. [PMID: 35743077 PMCID: PMC9224206 DOI: 10.3390/ijms23126639] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 02/04/2023] Open
Abstract
RNA interference (RNAi) is a powerful tool that is being increasingly utilized for crop protection against viruses, fungal pathogens, and insect pests. The non-transgenic approach of spray-induced gene silencing (SIGS), which relies on spray application of double-stranded RNA (dsRNA) to induce RNAi, has come to prominence due to its safety and environmental benefits in addition to its wide host range and high target specificity. However, along with promising results in recent studies, several factors limiting SIGS RNAi efficiency have been recognized in insects and plants. While sprayed dsRNA on the plant surface can produce a robust RNAi response in some chewing insects, plant uptake and systemic movement of dsRNA is required for delivery to many other target organisms. For example, pests such as sucking insects require the presence of dsRNA in vascular tissues, while many fungal pathogens are predominately located in internal plant tissues. Investigating the mechanisms by which sprayed dsRNA enters and moves through plant tissues and understanding the barriers that may hinder this process are essential for developing efficient ways to deliver dsRNA into plant systems. In this review, we assess current knowledge of the plant foliar and cellular uptake of dsRNA molecules. We will also identify major barriers to uptake, including leaf morphological features as well as environmental factors, and address methods to overcome these barriers.
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17
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Gupta D, Singh OW, Basavaraj YB, Roy A, Mukherjee SK, Mandal B. Direct Foliar Application of dsRNA Derived From the Full-Length Gene of NSs of Groundnut Bud Necrosis Virus Limits Virus Accumulation and Symptom Expression. FRONTIERS IN PLANT SCIENCE 2021; 12:734618. [PMID: 34950158 PMCID: PMC8688928 DOI: 10.3389/fpls.2021.734618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 11/09/2021] [Indexed: 05/31/2023]
Abstract
Groundnut bud necrosis virus (GBNV) is the most significant member of the genus Orthotospovirus occurring in the Indian subcontinent. There is hardly any effective measure to prevent GBNV in crop plants. In order to develop GBNV infection prevention procedure, we examined the effect of the direct foliar application of double-stranded RNA (dsRNA) derived from the full-length NSs gene (1,320 nucleotides) of GBNV. The bacterially expressed dsRNA to the non-structural (dsNSs) gene of GBNV was purified and delivered to plants as an aqueous suspension containing 0.01% Celite for evaluating its efficacy in preventing GBNV infection in systemic host, Nicotiana benthamiana as well as in local lesion and systemic host, cowpea cv. Pusa Komal (Vigna unguiculata). The dsNSs application and challenge-inoculation were conducted in three different combinations, where plants were challenge-inoculated with GBNV a day after, immediately, and a day before the application of dsNSs. N. benthamiana plants, which were not treated with dsRNA showed severe systemic wilting and death by 9-16 days post-inoculation (dpi). The non-treated cowpea plants exhibited many chlorotic and necrotic lesions on the cotyledonary leaves followed by systemic necrosis and death of the plants by 14-16 dpi. The dsNSs treated plants in all the combinations showed significant reduction of disease severity index in both N. benthamiana and cowpea. The treatment combination where the GBNV inoculation was conducted immediately after the dsNSs treatment was found to be the most effective treatment in preventing symptom expression. The viral RNA analysis by real time PCR also showed 20 and 12.5 fold reduction of GBNV in cowpea and N. benthamiana, respectively. Our results suggest that the foliar application of dsRNA derived from the full-length NSs gene of GBNV through Celite is successful in delivering long dsRNA leading to effective prevention of GBNV infection.
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18
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Topical Application of Escherichia coli-Encapsulated dsRNA Induces Resistance in Nicotiana benthamiana to Potato Viruses and Involves RDR6 and Combined Activities of DCL2 and DCL4. PLANTS 2021; 10:plants10040644. [PMID: 33805277 PMCID: PMC8067229 DOI: 10.3390/plants10040644] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/18/2022]
Abstract
Exogenous application of double-stranded RNAs (dsRNAs) for inducing virus resistance in plants represents an attractive alternative to transgene-based silencing approaches. However, improvement of dsRNA stability in natural conditions is required in order to provide long-term protection against the targeted virus. Here, we tested the protective effect of topical application of Escherichia coli-encapsulated dsRNA compared to naked dsRNA against single and dual infection by Potato virus X expressing the green fluorescent protein (PVX-GFP) and Potato virus Y (PVY) in Nicotiana benthamiana. We found that, in our conditions, the effectiveness of E. coli-encapsulated dsRNA in providing RNAi-mediated protection did not differ from that of naked dsRNA. dsRNA vaccination was partly effective against a dual infection by PVX-GFP and PVY, manifested by a delay in the expression of the synergistic symptoms at early times after inoculation. Using PVX-GFP as a reporter virus together with a suite of RNAi knockdown transgenic lines, we have also shown that RNA-directed RNA polymerase 6 and the combined activities of DICER-like 2 (DCL2) and DCL4 act to promote efficient resistance to virus infection conferred by topical application of dsRNA in N. benthamiana. Our results provide evidence that exogenous dsRNA molecules are processed by the RNA silencing pathways commonly used by the host in response to virus infection.
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