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Dalakouras A, Koidou V, Papadopoulou K. DsRNA-based pesticides: Considerations for efficiency and risk assessment. CHEMOSPHERE 2024; 352:141530. [PMID: 38401868 DOI: 10.1016/j.chemosphere.2024.141530] [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: 12/15/2023] [Revised: 02/05/2024] [Accepted: 02/21/2024] [Indexed: 02/26/2024]
Abstract
In view of the ongoing climate change and the ever-growing world population, novel agricultural solutions are required to ensure sustainable food supply. Microbials, natural substances, semiochemicals and double stranded RNAs (dsRNAs) are all considered potential low risk pesticides. DsRNAs function at the molecular level, targeting specific regions of specific genes of specific organisms, provided that they share a minimal sequence complementarity of approximately 20 nucleotides. Thus, dsRNAs may offer a great alternative to conventional chemicals in environmentally friendly pest control strategies. Any low-risk pesticide needs to be efficient and exhibit low toxicological potential and low environmental persistence. Having said that, in the current review, the mode of dsRNA action is explored and the parameters that need to be taken into consideration for the development of efficient dsRNA-based pesticides are highlighted. Moreover, since dsRNAs mode of action differs from those of synthetic pesticides, custom-made risk assessment schemes may be required and thus, critical issues related to the risk assessment of dsRNA pesticides are discussed here.
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Affiliation(s)
| | - Venetia Koidou
- ELGO-DIMITRA, Institute of Industrial and Forage Crops, Larissa, Greece; University of Thessaly, Department of Biochemistry and Biotechnology, Larissa, Greece
| | - Kalliope Papadopoulou
- University of Thessaly, Department of Biochemistry and Biotechnology, Larissa, Greece
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2
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Whitten MMA, Xue Q, Taning CNT, James R, Smagghe G, del Sol R, Hitchings M, Dyson P. A narrow host-range and lack of persistence in two non-target insect species of a bacterial symbiont exploited to deliver insecticidal RNAi in Western Flower Thrips. FRONTIERS IN INSECT SCIENCE 2023; 3:1093970. [PMID: 38469480 PMCID: PMC10926499 DOI: 10.3389/finsc.2023.1093970] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/31/2023] [Indexed: 03/13/2024]
Abstract
Introduction Insecticidal RNAi is a targeted pest insect population control measure. The specificity of insecticidal RNAi can theoretically be enhanced by using symbiotic bacteria with a narrow host range to deliver RNAi, an approach termed symbiont-mediated RNAi (SMR), a technology we have previously demonstrated in the globally-invasive pest species Western Flower Thrips (WFT). Methods Here we examine distribution of the two predominant bacterial symbionts of WFT, BFo1 and BFo2, among genome-sequenced insects. Moreover, we have challenged two non-target insect species with both bacterial species, namely the pollinating European bumblebee, Bombus terrestris, and an insect predator of WFT, the pirate bug Orius laevigatus. Results Our data indicate a very limited distribution of either symbiont among insects other than WFT. Moreover, whereas BFo1 could establish itself in both bees and pirate bugs, albeit with no significant effects on insect fitness, BFo2 was unable to persist in either species. Discussion In terms of biosafety, these data, together with its more specific growth requirements, vindicate the choice of BFo2 for delivery of RNAi and precision pest management of WFT.
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Affiliation(s)
- Miranda M. A. Whitten
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, United Kingdom
| | - Qi Xue
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Clauvis Nji Tizi Taning
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Reuben James
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, United Kingdom
| | - Guy Smagghe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Ricardo del Sol
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, United Kingdom
| | - Matthew Hitchings
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, United Kingdom
| | - Paul Dyson
- Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, United Kingdom
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3
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Tamayo B, Kercher K, Vosburg C, Massimino C, Jernigan MR, Hasan DL, Harper D, Mathew A, Adkins S, Shippy T, Hosmani PS, Flores-Gonzalez M, Panitz N, Mueller LA, Hunter WB, Benoit JB, Brown SJ, D’Elia T, Saha S. Annotation of glycolysis, gluconeogenesis, and trehaloneogenesis pathways provide insight into carbohydrate metabolism in the Asian citrus psyllid. GIGABYTE 2022; 2022:gigabyte41. [PMID: 36824510 PMCID: PMC9933520 DOI: 10.46471/gigabyte.41] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 02/11/2022] [Indexed: 11/09/2022] Open
Abstract
Citrus greening disease is caused by the pathogen Candidatus Liberibacter asiaticus and transmitted by the Asian citrus psyllid, Diaphorina citri. No curative treatment or significant prevention mechanism exists for this disease, which causes economic losses from reduced citrus production. A high-quality genome of D. citri is being manually annotated to provide accurate gene models to identify novel control targets and increase understanding of this pest. Here, we annotated 25 D. citri genes involved in glycolysis and gluconeogenesis, and seven in trehaloneogenesis. Comparative analysis showed that glycolysis genes in D. citri are highly conserved but copy numbers vary. Analysis of expression levels revealed upregulation of several enzymes in the glycolysis pathway in the thorax, consistent with the primary use of glucose by thoracic flight muscles. Manually annotating these core metabolic pathways provides accurate genomic foundation for developing gene-targeting therapeutics to control D. citri.
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Affiliation(s)
- Blessy Tamayo
- Indian River State College, Fort Pierce, FL 34981, USA
| | - Kyle Kercher
- Indian River State College, Fort Pierce, FL 34981, USA
| | - Chad Vosburg
- Indian River State College, Fort Pierce, FL 34981, USA
| | | | | | | | | | - Anuja Mathew
- Indian River State College, Fort Pierce, FL 34981, USA
| | - Samuel Adkins
- Indian River State College, Fort Pierce, FL 34981, USA
| | - Teresa Shippy
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | | | | | | | | | - Wayne B. Hunter
- US Department of Agriculture-Agricultural Research Service (USDA-ARS), US Horticultural Research Laboratory, Fort Pierce, FL 34945, USA
| | - Joshua B. Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Susan J. Brown
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Tom D’Elia
- Indian River State College, Fort Pierce, FL 34981, USA
| | - Surya Saha
- Boyce Thompson InstituteIthaca, NY 14853, USA,Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA, Corresponding author. E-mail:
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4
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Darlington M, Reinders JD, Sethi A, Lu AL, Ramaseshadri P, Fischer JR, Boeckman CJ, Petrick JS, Roper JM, Narva KE, Vélez AM. RNAi for Western Corn Rootworm Management: Lessons Learned, Challenges, and Future Directions. INSECTS 2022; 13:57. [PMID: 35055900 PMCID: PMC8779393 DOI: 10.3390/insects13010057] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 02/06/2023]
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is considered one of the most economically important pests of maize (Zea mays L.) in the United States (U.S.) Corn Belt with costs of management and yield losses exceeding USD ~1-2 billion annually. WCR management has proven challenging given the ability of this insect to evolve resistance to multiple management strategies including synthetic insecticides, cultural practices, and plant-incorporated protectants, generating a constant need to develop new management tools. One of the most recent developments is maize expressing double-stranded hairpin RNA structures targeting housekeeping genes, which triggers an RNA interference (RNAi) response and eventually leads to insect death. Following the first description of in planta RNAi in 2007, traits targeting multiple genes have been explored. In June 2017, the U.S. Environmental Protection Agency approved the first in planta RNAi product against insects for commercial use. This product expresses a dsRNA targeting the WCR snf7 gene in combination with Bt proteins (Cry3Bb1 and Cry34Ab1/Cry35Ab1) to improve trait durability and will be introduced for commercial use in 2022.
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Affiliation(s)
- Molly Darlington
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA; (M.D.); (J.D.R.)
| | - Jordan D. Reinders
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA; (M.D.); (J.D.R.)
| | - Amit Sethi
- Corteva Agriscience, Johnston, IA 50131, USA; (A.S.); (A.L.L.); (C.J.B.); (J.M.R.)
| | - Albert L. Lu
- Corteva Agriscience, Johnston, IA 50131, USA; (A.S.); (A.L.L.); (C.J.B.); (J.M.R.)
| | | | - Joshua R. Fischer
- Bayer Crop Science, Chesterfield, MO 63017, USA; (P.R.); (J.R.F.); (J.S.P.)
| | - Chad J. Boeckman
- Corteva Agriscience, Johnston, IA 50131, USA; (A.S.); (A.L.L.); (C.J.B.); (J.M.R.)
| | - Jay S. Petrick
- Bayer Crop Science, Chesterfield, MO 63017, USA; (P.R.); (J.R.F.); (J.S.P.)
| | - Jason M. Roper
- Corteva Agriscience, Johnston, IA 50131, USA; (A.S.); (A.L.L.); (C.J.B.); (J.M.R.)
| | | | - Ana M. Vélez
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA; (M.D.); (J.D.R.)
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Ramkumar G, Asokan R, Prasannakumar NR, Kariyanna B, Karthi S, Alwahibi MS, Elshikh MS, Abdel-Megeed A, Ghaith A, Senthil-Nathan S, Kalaivani K, Hunter WB, Krutmuang P. RNA Interference Suppression of v-ATPase B and Juvenile Hormone Binding Protein Genes Through Topically Applied dsRNA on Tomato Leaves: Developing Biopesticides to Control the South American Pinworm, Tuta absoluta (Lepidoptera: Gelechiidae). Front Physiol 2021; 12:742871. [PMID: 34867448 PMCID: PMC8637209 DOI: 10.3389/fphys.2021.742871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/20/2021] [Indexed: 11/23/2022] Open
Abstract
The South American pinworm Tuta absoluta (Meyrick) (Family: Gelechiidae) is one of the most devastating lepidopteran pests in the developing countries of South America, Africa, and Asia. This pest is classified as the most serious threat for tomato production worldwide. In the present study, we analyzed RNAi-mediated control through exogenously applied dsRNA delivery on tomato. The dsRNA treatments were made to target the juvenile hormone binding protein and the v-ATPase B. Both mRNA targets were cloned, validated by sequencing, and used to produce each dsRNA. After treatments the relative transcript expression was analyzed using qRTPCR to assess to efficacy of RNAi. A leaf-dip assay was used to provide late 2nd instar larvae three feeding access periods: 24, 48, and 72 h, to evaluate the effect of gene silencing of each target. Larvae were fed tomato leaves coated with five different RNAi concentrations (10, 20, 30, 40, and 50 micrograms/centimeter-squared), that suppressed two genes (juvenile hormone protein, JHBP, and vacuolar-type adenosine triphosphatase enzyme, v-ATPase). Treatments with dsRNA showed a significant increase in mortality at 24, 48, and 72 h after ingestion (P < 0.01, α = 0.05), along with reduced leaf damage, and increased feeding deterrence. The results suggest that these two RNAi products may provide a suitable treatment for control of this and other lepidopteran pests.
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Affiliation(s)
- Govindaraju Ramkumar
- Division of Biotechnology, ICAR-Indian Institute of Horticultural Research (IIHR), Bengaluru, India
| | - Ramasamy Asokan
- Division of Biotechnology, ICAR-Indian Institute of Horticultural Research (IIHR), Bengaluru, India
| | - N R Prasannakumar
- Division of Entomology and Nematology, ICAR-Indian Institute of Horticultural Research (IIHR), Bengaluru, India
| | - B Kariyanna
- Division of Biotechnology, ICAR-Indian Institute of Horticultural Research (IIHR), Bengaluru, India
| | - Sengodan Karthi
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Center for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Tirunelveli, India
| | - Mona S Alwahibi
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mohamed Soliman Elshikh
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed Abdel-Megeed
- Department of Plant Protection, Faculty of Agriculture Saba Basha, Alexandria University, Alexandria, Egypt
| | - Aml Ghaith
- Department of Zoology, Faculty of Science, Derna University, Derna, Libya
| | - Sengottayan Senthil-Nathan
- Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Center for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Tirunelveli, India
| | - Kandaswamy Kalaivani
- Post Graduate and Research Center, Department of Zoology, Sri Parasakthi College for Women, Tirunelveli, India
| | - Wayne Brian Hunter
- U.S. Horticultural Research Laboratory, United States Department of Agriculture, Agricultural Research Service, Fort Pierce, FL, United States
| | - Patcharin Krutmuang
- Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand.,Innovative Agriculture Research Center, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand
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Hunter WB, Wintermantel WM. Optimizing Efficient RNAi-Mediated Control of Hemipteran Pests (Psyllids, Leafhoppers, Whitefly): Modified Pyrimidines in dsRNA Triggers. PLANTS 2021; 10:plants10091782. [PMID: 34579315 PMCID: PMC8472347 DOI: 10.3390/plants10091782] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/23/2021] [Accepted: 08/23/2021] [Indexed: 01/09/2023]
Abstract
The advantages from exogenously applied RNAi biopesticides have yet to be realized in through commercialization due to inconsistent activity of the dsRNA trigger, and the activity level of RNAi suppression. This has prompted research on improving delivery methods for applying exogenous dsRNA into plants and insects for the management of pests and pathogens. Another aspect to improve RNAi activity is the incorporation of modified 2′-F pyrimidine nucleotides into the dsRNA trigger. Modified dsRNA incorporating 32–55% of the 2′-F- nucleotides produced improved RNAi activity that increased insect mortality by 12–35% greater than non-modified dsRNA triggers of the same sequence. These results were repeatable across multiple Hemiptera: the Asian citrus psyllid (Diaphorina citri, Liviidae); whitefly (Bemisia tabaci, Aleyroididae); and the glassy-winged sharpshooter (Homalodisca vitripennis, Cicadellidae). Studies using siRNA with modified 2′-F- pyrimidines in mammalian cells show they improved resistance to degradation from nucleases, plus result in greater RNAi activity, due to increase concentrations and improved binding affinity to the mRNA target. Successful RNAi biopesticides of the future will be able to increase RNAi repeatability in the field, by incorporating modifications of the dsRNA, such as 2′-F- pyrimidines, that will improve delivery after applied to fruit trees or crop plants, with increased activity after ingestion by insects. Costs of RNA modification have decreased significantly over the past few years such that biopesticides can now compete on pricing with commercial chemical products.
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Affiliation(s)
- Wayne Brian Hunter
- U.S. Horticultural Research Laboratory, U.S. Department of Agriculture, Agriculture Research Service, Subtropical Insects Res., Fort Pierce, FL 34945, USA
- Correspondence:
| | - William M. Wintermantel
- U.S. Department of Agriculture, Agriculture Research Service, Crop Improvement and Protection Research, Salinas, CA 93905, USA;
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Naegeli H, Bresson J, Dalmay T, Dewhurst IC, Epstein MM, Guerche P, Hejatko J, Moreno FJ, Mullins E, Nogué F, Rostoks N, Sánchez Serrano JJ, Savoini G, Veromann E, Veronesi F, Bonsall MB, Mumford J, Wimmer EA, Devos Y, Paraskevopoulos K, Firbank LG. Adequacy and sufficiency evaluation of existing EFSA guidelines for the molecular characterisation, environmental risk assessment and post-market environmental monitoring of genetically modified insects containing engineered gene drives. EFSA J 2020; 18:e06297. [PMID: 33209154 PMCID: PMC7658669 DOI: 10.2903/j.efsa.2020.6297] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Advances in molecular and synthetic biology are enabling the engineering of gene drives in insects for disease vector/pest control. Engineered gene drives (that bias their own inheritance) can be designed either to suppress interbreeding target populations or modify them with a new genotype. Depending on the engineered gene drive system, theoretically, a genetic modification of interest could spread through target populations and persist indefinitely, or be restricted in its spread or persistence. While research on engineered gene drives and their applications in insects is advancing at a fast pace, it will take several years for technological developments to move to practical applications for deliberate release into the environment. Some gene drive modified insects (GDMIs) have been tested experimentally in the laboratory, but none has been assessed in small-scale confined field trials or in open release trials as yet. There is concern that the deliberate release of GDMIs in the environment may have possible irreversible and unintended consequences. As a proactive measure, the European Food Safety Authority (EFSA) has been requested by the European Commission to review whether its previously published guidelines for the risk assessment of genetically modified animals (EFSA, 2012 and 2013), including insects (GMIs), are adequate and sufficient for GDMIs, primarily disease vectors, agricultural pests and invasive species, for deliberate release into the environment. Under this mandate, EFSA was not requested to develop risk assessment guidelines for GDMIs. In this Scientific Opinion, the Panel on Genetically Modified Organisms (GMO) concludes that EFSA's guidelines are adequate, but insufficient for the molecular characterisation (MC), environmental risk assessment (ERA) and post-market environmental monitoring (PMEM) of GDMIs. While the MC,ERA and PMEM of GDMIs can build on the existing risk assessment framework for GMIs that do not contain engineered gene drives, there are specific areas where further guidance is needed for GDMIs.
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Romeis J, Widmer F. Assessing the Risks of Topically Applied dsRNA-Based Products to Non-target Arthropods. FRONTIERS IN PLANT SCIENCE 2020; 11:679. [PMID: 32582240 PMCID: PMC7289159 DOI: 10.3389/fpls.2020.00679] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 04/30/2020] [Indexed: 05/17/2023]
Abstract
RNA interference (RNAi) is a powerful technology that offers new opportunities for pest control through silencing of genes that are essential for the survival of arthropod pests. The approach relies on sequence-specificity of applied double-stranded (ds) RNA that can be designed to have a very narrow spectrum of both the target gene product (RNA) as well as the target organism, and thus allowing highly targeted pest control. Successful RNAi has been reported from a number of arthropod species belonging to various orders. Pest control may be achieved by applying dsRNA as foliar sprays. One of the main concerns related to the use of dsRNA is adverse environmental effects particularly on valued non-target species. Arthropods form an important part of the biodiversity in agricultural landscapes and contribute important ecosystem services. Consequently, environmental risk assessment (ERA) for potential impacts that plant protection products may have on valued non-target arthropods is legally required prior to their placement on the market. We describe how problem formulation can be used to set the context and to develop plausible pathways on how the application of dsRNA-based products could harm valued non-target arthropod species, such as those contributing to biological pest control. The current knowledge regarding the exposure to and the hazard posed by dsRNA in spray products for non-target arthropods is reviewed and suggestions are provided on how to select the most suitable test species and to conduct laboratory-based toxicity studies that provide robust, reliable and interpretable results to support the ERA.
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Affiliation(s)
- Jörg Romeis
- Research Division Agroecology and Environment, Agroscope, Zurich, Switzerland
| | - Franco Widmer
- Competence Division Method Development and Analytics, Agroscope, Zurich, Switzerland
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