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Somers DJ, Kushner DB, McKinnis AR, Mehmedovic D, Flame RS, Arnold TM. Epigenetic weapons in plant-herbivore interactions: Sulforaphane disrupts histone deacetylases, gene expression, and larval development in Spodoptera exigua while the specialist feeder Trichoplusia ni is largely resistant to these effects. PLoS One 2023; 18:e0293075. [PMID: 37856454 PMCID: PMC10586618 DOI: 10.1371/journal.pone.0293075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/03/2023] [Indexed: 10/21/2023] Open
Abstract
Cruciferous plants produce sulforaphane (SFN), an inhibitor of nuclear histone deacetylases (HDACs). In humans and other mammals, the consumption of SFN alters enzyme activities, DNA-histone binding, and gene expression within minutes. However, the ability of SFN to act as an HDAC inhibitor in nature, disrupting the epigenetic machinery of insects feeding on these plants, has not been explored. Here, we demonstrate that SFN consumed in the diet inhibits the activity of HDAC enzymes and slows the development of the generalist grazer Spodoptera exigua, in a dose-dependent fashion. After consuming SFN for seven days, the activities of HDAC enzymes in S. exigua were reduced by 50%. Similarly, larval mass was reduced by 50% and pupation was delayed by 2-5 days, with no additional mortality. Similar results were obtained when SFN was applied topically to eggs. RNA-seq analyses confirm that SFN altered the expression of thousands of genes in S. exigua. Genes associated with energy conversion pathways were significantly downregulated while those encoding for ribosomal proteins were dramatically upregulated in response to the consumption of SFN. In contrast, the co-evolved specialist feeder Trichoplusia ni was not negatively impacted by SFN, whether it was consumed in their diet at natural concentrations or applied topically to eggs. The activities of HDAC enzymes were not inhibited and development was not disrupted. In fact, SFN exposure sometimes accelerated T. ni development. RNA-seq analyses revealed that the consumption of SFN alters gene expression in T. ni in similar ways, but to a lesser degree, compared to S. exigua. This apparent resistance of T. ni can be overwhelmed by unnaturally high levels of SFN or by exposure to more powerful pharmaceutical HDAC inhibitors. These results demonstrate that dietary SFN interferes with the epigenetic machinery of insects, supporting the hypothesis that plant-derived HDAC inhibitors serve as "epigenetic weapons" against herbivores.
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Affiliation(s)
- Dana J. Somers
- Department of Biology, Program in Biochemistry and Molecular Biology, Dickinson College, Carlisle, PA United States of America
| | - David B. Kushner
- Department of Biology, Program in Biochemistry and Molecular Biology, Dickinson College, Carlisle, PA United States of America
| | - Alexandria R. McKinnis
- Department of Biology, Program in Biochemistry and Molecular Biology, Dickinson College, Carlisle, PA United States of America
| | - Dzejlana Mehmedovic
- Department of Biology, Program in Biochemistry and Molecular Biology, Dickinson College, Carlisle, PA United States of America
| | - Rachel S. Flame
- Department of Biology, Program in Biochemistry and Molecular Biology, Dickinson College, Carlisle, PA United States of America
| | - Thomas M. Arnold
- Department of Biology, Program in Biochemistry and Molecular Biology, Dickinson College, Carlisle, PA United States of America
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Chen B, Chen Y, Chen H, Liang Z, Chen J, Wu R, Zhang T, Zhou G, Yang X. Identification, characterization and prevalence in southern China of a new iflavirus in the leafhopper Recilia dorsalis (Hemiptera: Cicadellidae). Virus Res 2023; 323:199005. [PMID: 36410611 PMCID: PMC10194291 DOI: 10.1016/j.virusres.2022.199005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/11/2022] [Accepted: 11/16/2022] [Indexed: 11/22/2022]
Abstract
The leafhopper Recilia dorsalis (Hemiptera: Cicadellidae) is not only a significant pest in agriculture but also an important vector involved in transmitting numerous pathogens that are known to cause economic losses by affecting rice crops. Here, a new iflavirus was discovered in the leafhopper R. dorsalis by employing a transcriptomic approach. The complete viral genome was determined to be 10,711 nucleotides (nt) in length and contains a single open reading frame (ORF) encoding a putative polyprotein comprised of 3,161 amino acids (aa), which is flanked by 5' and 3' untranslated regions. The full viral genome nt and the deduced polyprotein aa sequence showed the highest similarity (71.6% and 77.8%, respectively) with Langfang leafhopper iflavirus. Phylogenetic analysis based on the RdRp domain indicated that the isolated virus, which we have tentatively named Recilia dorsalis iflavirus 2 (RdIV2), is clustered with the members of the family Iflaviridae. Moreover, the results of our surveys indicate that RdIV2 predominates in southwestern Guangdong and southeastern Guangxi, China, and was absent in the other three species of leafhoppers; Nephotettix cincticeps, N. virescens and N. nigropictus. Notably, R. dorsalis was found to be co-infected with RdIV2 and rice stripe mosaic virus (RSMV; a well-known rice-infecting virus vectored by R. dorsalis) in rice fields, although the co-infection rate is low.
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Affiliation(s)
- Biao Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Yulu Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Huazhou Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Zhenyi Liang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Jiahao Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Ruifeng Wu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Tong Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China
| | - Guohui Zhou
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
| | - Xin Yang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
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Hussain AG, Wennmann JT, Goergen G, Bryon A, Ros VI. Viruses of the Fall Armyworm Spodoptera frugiperda: A Review with Prospects for Biological Control. Viruses 2021; 13:v13112220. [PMID: 34835026 PMCID: PMC8625175 DOI: 10.3390/v13112220] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/29/2021] [Accepted: 10/30/2021] [Indexed: 11/17/2022] Open
Abstract
The fall armyworm (FAW), Spodoptera frugiperda, is a native pest species in the Western hemisphere. Since it was first reported in Africa in 2016, FAW has spread throughout the African continent and is now also present in several countries in Asia as well as Australia. The invasion of FAW in these areas has led to a high yield reduction in crops, leading to huge economic losses. FAW management options in the newly invaded areas are limited and mainly rely on the use of synthetic pesticides. Since there is a risk of resistance development against pesticides in addition to the negative environmental and human health impacts, other effective, sustainable, and cost-efficient control alternatives are desired. Insect pathogenic viruses fulfil these criteria as they are usually effective and highly host-specific with no significant harmful effect on beneficial insects and non-target organisms. In this review, we discuss all viruses known from FAW and their potential to be used for biological control. We specifically focus on baculoviruses and describe the recent advancements in the use of baculoviruses for biological control in the native geographic origin of FAW, and their potential use in the newly invaded areas. Finally, we identify current knowledge gaps and suggest new avenues for productive research on the use of viruses as a biopesticide against FAW.
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Affiliation(s)
- Ahmed G. Hussain
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; (A.G.H.); (A.B.)
| | - Jörg T. Wennmann
- Julius Kühn Institute (JKI)—Federal Research Centre for Cultivated Plants, Institute for Biological Control, Heinrichstr. 243, 64287 Darmstadt, Germany;
| | - Georg Goergen
- International Institute of Tropical Agriculture (IITA), Biological Control Centre for Africa, Cotonou 08 BP 0932, Benin;
| | - Astrid Bryon
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; (A.G.H.); (A.B.)
| | - Vera I.D. Ros
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; (A.G.H.); (A.B.)
- Correspondence:
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Roy MC, Ahmed S, Mollah MMI, Kim Y. Antiviral Treatment Reveals a Cooperative Pathogenicity of Baculovirus and Iflavirus in Spodoptera exigua, a Lepidopteran Insect. J Microbiol Biotechnol 2021; 31:529-539. [PMID: 33526755 PMCID: PMC9723280 DOI: 10.4014/jmb.2012.12045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 12/15/2022]
Abstract
NPVThe beet armyworm, Spodoptera exigua, is a serious insect pest infesting various vegetable crops. Two infectious insect viruses, baculovirus and iflavirus, are known to induce epizootics in S. exigua populations. Indeed, some laboratory colonies have appeared to be covertly infected by these viruses. Diagnostic PCR tests detected two different viruses: Spodoptera exigua multiple nucleopolyhedrosis virus (SeMNPV) and iflaviruses (SeIfV1 and SeIfV2). Viral extract from dead larvae of S. exigua could infect Sf9 cells and produce occlusion bodies (OBs). Feeding OBs to asymptomatic larvae of S. exigua caused significant viral disease. Interestingly, both SeIfV1 and SeIfV2 increased their titers at late larval stages. Sterilization of laid eggs with 1% sodium hypochloride significantly reduced SeMNPV titers and increased larval survival rate. Doublestranded RNA (dsRNA) specific to SeIfV1 or SeIfV2 significantly reduced viral titers and increased larval survival rate. To continuously feed dsRNA, a recombinant Escherichia coli HT115 expressing SeIfV1-dsRNA was constructed with an L4440 expression vector. Adding this recombinant E. coli to the artificial diet significantly reduced the SeIfV1 titer and increased larval survival. These results indicate that laboratory colony collapse of S. exigua is induced by multiple viral infections. In addition, either suppression of SeMNPV or SeIfV infection significantly increased larval survival, suggesting a cooperative pathogenicity between baculovirus and iflavirus against S. exigua.
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Affiliation(s)
- Miltan Chandra Roy
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, Republic of Korea
| | - Shabbir Ahmed
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, Republic of Korea
| | - Md. Mahi Imam Mollah
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, Republic of Korea
| | - Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong 36729, Republic of Korea,Corresponding author E-mail:
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Virus Prospecting in Crickets-Discovery and Strain Divergence of a Novel Iflavirus in Wild and Cultivated Acheta domesticus. Viruses 2021; 13:v13030364. [PMID: 33669085 PMCID: PMC7996529 DOI: 10.3390/v13030364] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 12/19/2022] Open
Abstract
Orthopteran insects have high reproductive rates leading to boom-bust population dynamics with high local densities that are ideal for short, episodic disease epidemics. Viruses are particularly well suited for such host population dynamics, due to their supreme ability to adapt to changing transmission criteria. However, very little is known about the viruses of Orthopteran insects. Since Orthopterans are increasingly reared commercially, for animal feed and human consumption, there is a risk that viruses naturally associated with these insects can adapt to commercial rearing conditions, and cause disease. We therefore explored the virome of the house cricket Acheta domesticus, which is both part of the natural Swedish landscape and reared commercially for the pet feed market. Only 1% of the faecal RNA and DNA from wild-caught A. domesticus consisted of viruses. These included both known and novel viruses associated with crickets/insects, their bacterial-fungal microbiome, or their plant food. Relatively abundant among these viral Operational Taxonomic Units (OTUs) was a novel Iflavirus, tentatively named Acheta domesticus Iflavirus (AdIV). Quantitative analyses showed that AdIV was also abundant in frass and insect samples from commercially reared crickets. Interestingly, the wild and commercial AdIV strains had short, extremely divergent variation hotspots throughout the genome, which may indicate specific adaptation to their hosts’ distinct rearing environments.
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Jia W, Wang F, Li J, Chang X, Yang Y, Yao H, Bao Y, Song Q, Ye G. A Novel Iflavirus Was Discovered in Green Rice Leafhopper Nephotettix cincticeps and Its Proliferation Was Inhibited by Infection of Rice Dwarf Virus. Front Microbiol 2021; 11:621141. [PMID: 33488564 PMCID: PMC7820178 DOI: 10.3389/fmicb.2020.621141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 12/01/2020] [Indexed: 11/15/2022] Open
Abstract
The green rice leafhopper, Nephotettix cincticeps (Hemiptera: Cicadellidae), is a key insect vector transmitting rice dwarf virus (RDV) that causes rice dwarf disease. We discovered a novel iflavirus from the transcriptomes of N. cincticeps and named it as Nephotettix cincticeps positive-stranded RNA virus-1 (NcPSRV-1). The viral genome consists of 10,524 nucleotides excluding the poly(A) tail and contains one predicted open reading frame encoding a polyprotein of 3,192 amino acids, flanked by 5' and 3' untranslated regions. NcPSRV-1 has a typical iflavirus genome arrangement and is clustered with the members of the family Iflaviridae in the phylogenetic analysis. NcPSRV-1 was detected in all tested tissues and life stages of N. cincticeps and could be transmitted horizontally and vertically. Moreover, NcPSRV-1 had high prevalence in the laboratory populations and was widely spread in field populations of N. cincticeps. NcPSRV-1 could also infect the two-striped leafhopper, Nephotettix apicalis, at a 3.33% infection rate, but was absent in the zigzag leafhopper, Recilia dorsalis, and rice Oryza sativa variety TN1. The infection of RDV altered the viral load and infection rate of NcPSRV-1 in N. cincticeps, for which it seems that RDV has an antagonistic effect on NcPSRV-1 infection in the host.
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Affiliation(s)
- Wenxi Jia
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Fei Wang
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Jingjing Li
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China.,Division of Plant Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, United States
| | - Xuefei Chang
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Yi Yang
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Hongwei Yao
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Yanyuan Bao
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Qisheng Song
- Division of Plant Sciences, College of Agriculture, Food and Natural Resources, University of Missouri, Columbia, MO, United States
| | - Gongyin Ye
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
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7
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Martínez-Solís M, Collado MC, Herrero S. Influence of Diet, Sex, and Viral Infections on the Gut Microbiota Composition of Spodoptera exigua Caterpillars. Front Microbiol 2020; 11:753. [PMID: 32435237 PMCID: PMC7218101 DOI: 10.3389/fmicb.2020.00753] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/30/2020] [Indexed: 11/25/2022] Open
Abstract
The gut microbiota plays essential roles in processes related with metabolism, physiology, and immunity in all organisms, including insects. In the present work, we performed a broad analysis of the Spodoptera exigua gut microbiota, a major agricultural pest. We analyzed the influence of multiple parameters such as diet, geographic location, sex, or viral infections on S. exigua caterpillar gut microbiota composition. Our study revealed a high variability in bacterial composition among individuals, and a major influence of environmental bacteria (including those acquired through diet) on the gut microbiota composition, supporting previous studies that claim resident microbiota are lacking in caterpillars. Previous studies with laboratory-reared insects showed that changes in caterpillar gut bacterial composition affect the insecticidal properties of entomopathogenic viruses and bacteria. Our study revealed different microbiota composition in field insects carrying a natural viral infection with Spodoptera exigua nucleopolyhedrovirus (SeMNPV) and/or Spodoptera exigua iflavirus 1 (SeIV1). Few taxa can be specifically associated with the infection, suggesting microbiota influence the infective process of these natural pathogens, and providing new strategies for insect pest management.
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Affiliation(s)
- María Martínez-Solís
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Departamento de Genética, Universitat de València, Valencia, Spain
| | - María Carmen Collado
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas (IATA-CSIC), Valencia, Spain
| | - Salvador Herrero
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Departamento de Genética, Universitat de València, Valencia, Spain
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Carballo A, Williams T, Murillo R, Caballero P. Iflavirus Covert Infection Increases Susceptibility to Nucleopolyhedrovirus Disease in Spodoptera exigua. Viruses 2020; 12:E509. [PMID: 32380682 PMCID: PMC7290388 DOI: 10.3390/v12050509] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 01/04/2023] Open
Abstract
Naturally occurring covert infections in lepidopteran populations can involve multiple viruses with potentially different transmission strategies. In this study, we characterized covert infection by two RNA viruses, Spodoptera exigua iflavirus 1 (SeIV-1) and Spodoptera exigua iflavirus 2 (SeIV-2) (family Iflaviridae) that naturally infect populations of Spodoptera exigua, and examined their influence on susceptibility to patent disease by the nucleopolyhedrovirus Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) (family Baculoviridae). The abundance of SeIV-1 genomes increased up to ten-thousand-fold across insect developmental stages after surface contamination of host eggs with a mixture of SeIV-1 and SeIV-2 particles, whereas the abundance of SeIV-2 remained constant across all developmental stages. Low levels of SeIV-2 infection were detected in all groups of insects, including those that hatched from surface-decontaminated egg masses. SeIV-1 infection resulted in reduced larval weight gain, and an unbalanced sex ratio, whereas larval developmental time, pupal weight, and adult emergence and fecundity were not significantly affected in infected adults. The inoculation of S. exigua egg masses with iflavirus, followed by a subsequent infection with SeMNPV, resulted in an additive effect on larval mortality. The 50% lethal concentration (LC50) of SeMNPV was reduced nearly 4-fold and the mean time to death was faster by 12 h in iflavirus-treated insects. These results suggest that inapparent iflavirus infections may be able to modulate the host response to a new pathogen, a finding that has particular relevance to the use of SeMNPV as the basis for biological pest control products.
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Affiliation(s)
- Arkaitz Carballo
- Institute for Multidisciplinary Research in Applied Biology, Universidad Pública de Navarra, 31006 Pamplona, Spain; (A.C.); (P.C.)
- Departamento de Biotecnología, Agronomía y Alimentos, Universidad Pública de Navarra, 31006 Pamplona, Spain
| | | | - Rosa Murillo
- Institute for Multidisciplinary Research in Applied Biology, Universidad Pública de Navarra, 31006 Pamplona, Spain; (A.C.); (P.C.)
- Departamento de Biotecnología, Agronomía y Alimentos, Universidad Pública de Navarra, 31006 Pamplona, Spain
| | - Primitivo Caballero
- Institute for Multidisciplinary Research in Applied Biology, Universidad Pública de Navarra, 31006 Pamplona, Spain; (A.C.); (P.C.)
- Departamento de Biotecnología, Agronomía y Alimentos, Universidad Pública de Navarra, 31006 Pamplona, Spain
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Lüthi MN, Vorburger C, Dennis AB. A Novel RNA Virus in the Parasitoid Wasp Lysiphlebus fabarum: Genomic Structure, Prevalence, and Transmission. Viruses 2020; 12:E59. [PMID: 31947801 PMCID: PMC7019493 DOI: 10.3390/v12010059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/19/2019] [Accepted: 12/31/2019] [Indexed: 12/30/2022] Open
Abstract
We report on a novel RNA virus infecting the wasp Lysiphlebus fabarum, a parasitoid of aphids. This virus, tentatively named "Lysiphlebus fabarum virus" (LysV), was discovered in transcriptome sequences of wasps from an experimental evolution study in which the parasitoids were allowed to adapt to aphid hosts (Aphis fabae) with or without resistance-conferring endosymbionts. Based on phylogenetic analyses of the viral RNA-dependent RNA polymerase (RdRp), LysV belongs to the Iflaviridae family in the order of the Picornavirales, with the closest known relatives all being parasitoid wasp-infecting viruses. We developed an endpoint PCR and a more sensitive qPCR assay to screen for LysV in field samples and laboratory lines. These screens verified the occurrence of LysV in wild parasitoids and identified the likely wild-source population for lab infections in Western Switzerland. Three viral haplotypes could be distinguished in wild populations, of which two were found in the laboratory. Both vertical and horizontal transmission of LysV were demonstrated experimentally, and repeated sampling of laboratory populations suggests that the virus can form persistent infections without obvious symptoms in infected wasps.
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Affiliation(s)
- Martina N. Lüthi
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Christoph Vorburger
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Alice B. Dennis
- Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland; (C.V.); (A.B.D.)
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
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Santos D, Mingels L, Vogel E, Wang L, Christiaens O, Cappelle K, Wynant N, Gansemans Y, Van Nieuwerburgh F, Smagghe G, Swevers L, Vanden Broeck J. Generation of Virus- and dsRNA-Derived siRNAs with Species-Dependent Length in Insects. Viruses 2019; 11:v11080738. [PMID: 31405199 PMCID: PMC6723321 DOI: 10.3390/v11080738] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 01/01/2023] Open
Abstract
Double-stranded RNA (dsRNA) molecules of viral origin trigger a post-transcriptional gene-silencing mechanism called RNA interference (RNAi). Specifically, virally derived dsRNA is recognized and cleaved by the enzyme Dicer2 into short interfering RNAs (siRNAs), which further direct sequence-specific RNA silencing, ultimately silencing replication of the virus. Notably, RNAi can also be artificially triggered by the delivery of gene-specific dsRNA, thereby leading to endogenous gene silencing. This is a widely used technology that holds great potential to contribute to novel pest control strategies. In this regard, research efforts have been set to find methods to efficiently trigger RNAi in the field. In this article, we demonstrate the generation of dsRNA- and/or virus-derived siRNAs—the main RNAi effectors—in six insect species belonging to five economically important orders (Lepidoptera, Orthoptera, Hymenoptera, Coleoptera, and Diptera). In addition, we describe that the siRNA length distribution is species-dependent. Taken together, our results reveal interspecies variability in the (antiviral) RNAi mechanism in insects and show promise to contribute to future research on (viral-based) RNAi-triggering mechanisms in this class of animals.
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Affiliation(s)
- Dulce Santos
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, 3000 Leuven, Belgium.
| | - Lina Mingels
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, 3000 Leuven, Belgium
| | - Elise Vogel
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, 3000 Leuven, Belgium
| | - Luoluo Wang
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
| | - Olivier Christiaens
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
| | - Kaat Cappelle
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
| | - Niels Wynant
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, 3000 Leuven, Belgium
| | - Yannick Gansemans
- Laboratory of Pharmaceutical Biotechnology, Faculty of Pharmaceutical Sciences, Ghent University, 9000 Ghent, Belgium
| | - Filip Van Nieuwerburgh
- Laboratory of Pharmaceutical Biotechnology, Faculty of Pharmaceutical Sciences, Ghent University, 9000 Ghent, Belgium
| | - Guy Smagghe
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology Group, Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", 15310 Athens, Greece
| | - Jozef Vanden Broeck
- Research Group of Molecular Developmental Physiology and Signal Transduction, KU Leuven, 3000 Leuven, Belgium
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Lin J, Ye R, Thekke-Veetil T, Staton ME, Arelli PR, Bernard EC, Hewezi T, Domier LL, Hajimorad MR. A novel picornavirus-like genome from transcriptome sequencing of sugar beet cyst nematode represents a new putative genus. J Gen Virol 2018; 99:1418-1424. [PMID: 30156527 DOI: 10.1099/jgv.0.001139] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Analysis of transcriptome sequence data from eggs and second-stage juveniles (J2s) of sugar beet cyst nematode (SBCN, Heterodera schachtii) identified the full-length genome of a positive-sense single-stranded RNA virus, provisionally named sugar beet cyst nematode virus 1 (SBCNV1). The SBCNV1 sequence was detected in both eggs and J2s, indicating its possible vertical transmission. The 9503-nucleotide genome sequence contains a single long open reading frame, which was predicted to encode a polyprotein with conserved domains for picornaviral structural proteins proximal to its amino terminus and RNA helicase, cysteine proteinase and RNA-dependent RNA polymerase (RdRp) conserved domains proximal to its carboxyl terminus, hallmarks of viruses belonging to the order Picornavirales. Phylogenetic analysis of the predicted SBCNV1 RdRp amino acid sequence indicated that the SBCNV1 sequence is most closely related to members of the family Secoviridae, which includes genera of nematode-transmitted plant-infecting viruses. SBCNV1 represents the first fully sequenced viral genome from SBCN.
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Affiliation(s)
- Jingyu Lin
- 1Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA
| | - Rongjian Ye
- 1Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA.,†Present address: Life Science and Technology Center, China National Seed Group Company Limited, Wuhan 430075, PR China
| | | | - Margaret E Staton
- 1Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA
| | - Prakash R Arelli
- 3Crop Genetics Research Unit, USDA-ARS, 605 Airways Blvd., Jackson, TN 38301, USA
| | - Ernest C Bernard
- 1Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA
| | - Tarek Hewezi
- 4Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA
| | - Leslie L Domier
- 2Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA.,5Soybean/Maize Germplasm, Pathology, and Genetics Research Unit, USDA-ARS, Urbana, IL 61801, USA
| | - M R Hajimorad
- 1Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA
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12
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Insect-specific viruses: from discovery to potential translational applications. Curr Opin Virol 2018; 33:33-41. [PMID: 30048906 DOI: 10.1016/j.coviro.2018.07.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 06/29/2018] [Accepted: 07/04/2018] [Indexed: 12/17/2022]
Abstract
Over the past decade the scientific community has experienced a new age of virus discovery in arthropods in general, and in insects in particular. Next generation sequencing and advanced bioinformatics tools have provided new insights about insect viromes and viral evolution. In this review, we discuss some high-throughput sequencing technologies used to discover viruses in insects and the challenges raised in data interpretations. Additionally, the discovery of these novel viruses that are considered as insect-specific viruses (ISVs) has gained increasing attention in their potential use as biological agents. As example, we show how the ISV Nhumirim virus was used to reduce West Nile virus transmission when co-infecting the mosquito vector. We also discuss new translational opportunities of using ISVs to limit insect vector competence by using them to interfere with pathogen acquisition, to directly target the insect vector or to confer pathogen resistance by the insect vector.
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13
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Carballo A, Murillo R, Jakubowska A, Herrero S, Williams T, Caballero P. Co-infection with iflaviruses influences the insecticidal properties of Spodoptera exigua multiple nucleopolyhedrovirus occlusion bodies: Implications for the production and biosecurity of baculovirus insecticides. PLoS One 2017; 12:e0177301. [PMID: 28475633 PMCID: PMC5419652 DOI: 10.1371/journal.pone.0177301] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 04/25/2017] [Indexed: 11/18/2022] Open
Abstract
Biological insecticides based on Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) can efficiently control S. exigua larvae on field and greenhouse crops in many parts of the world. Spanish wild populations and laboratory colonies of S. exigua are infected by two iflaviruses (SeIV-1 and SeIV-2). Here we evaluated the effect of iflavirus co-infection on the insecticidal characteristics of SeMNPV occlusion bodies (OBs). Overall, iflavirus co-inoculation consistently reduced median lethal concentrations (LC50) for SeMNPV OBs compared to larvae infected with SeMNPV alone. However, the speed of kill of SeMNPV was similar in the presence or absence of the iflaviruses. A reduction of the weight gain (27%) associated with iflavirus infection resulted in a 30% reduction in total OB production per larva. Adult survivors of SeMNPV OB inoculation were examined for covert infection. SeMNPV DNA was found to be present at a high prevalence in all SeIV-1 and SeIV-2 co-infection treatments. Interestingly, co-inoculation of SeMNPV with SeIV-2 alone or in mixtures with SeIV-1 resulted in a significant increase in the SeMNPV load of sublethally infected adults, suggesting a role for SeIV-2 in vertical transmission or reactivation of sublethal SeMNPV infections. In conclusion, iflaviruses are not desirable in insect colonies used for large scale baculovirus production, as they may result in diminished larval growth, reduced OB production and, depending on their host-range, potential risks to non-target Lepidoptera.
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Affiliation(s)
- Arkaitz Carballo
- Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, Navarra, Spain
- Departamento de Producción Agraria, Universidad Pública de Navarra, Navarra, Spain
| | - Rosa Murillo
- Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, Navarra, Spain
- Departamento de Producción Agraria, Universidad Pública de Navarra, Navarra, Spain
| | - Agata Jakubowska
- Departamento de Genética, Universitat de Valencia, Valencia, Spain
| | - Salvador Herrero
- Departamento de Genética, Universitat de Valencia, Valencia, Spain
| | | | - Primitivo Caballero
- Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, Navarra, Spain
- Departamento de Producción Agraria, Universidad Pública de Navarra, Navarra, Spain
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14
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Maciel-Vergara G, Ros VID. Viruses of insects reared for food and feed. J Invertebr Pathol 2017; 147:60-75. [PMID: 28189501 DOI: 10.1016/j.jip.2017.01.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 01/26/2017] [Accepted: 01/31/2017] [Indexed: 02/07/2023]
Abstract
The use of insects as food for humans or as feed for animals is an alternative for the increasing high demand for meat and has various environmental and social advantages over the traditional intensive production of livestock. Mass rearing of insects, under insect farming conditions or even in industrial settings, can be the key for a change in the way natural resources are utilized in order to produce meat, animal protein and a list of other valuable animal products. However, because insect mass rearing technology is relatively new, little is known about the different factors that determine the quality and yield of the production process. Obtaining such knowledge is crucial for the success of insect-based product development. One of the issues that is likely to compromise the success of insect rearing is the outbreak of insect diseases. In particular, viral diseases can be devastating for the productivity and the quality of mass rearing systems. Prevention and management of viral diseases imply the understanding of the different factors that interact in insect mass rearing. This publication provides an overview of the known viruses in insects most commonly reared for food and feed. Nowadays with large-scale sequencing techniques, new viruses are rapidly being discovered. We discuss factors affecting the emergence of viruses in mass rearing systems, along with virus transmission routes. Finally we provide an overview of the wide range of measures available to prevent and manage virus outbreaks in mass rearing systems, ranging from simple sanitation methods to highly sophisticated methods including RNAi and transgenics.
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Affiliation(s)
- Gabriela Maciel-Vergara
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
| | - Vera I D Ros
- Laboratory of Virology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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15
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Jakubowska AK, Murillo R, Carballo A, Williams T, van Lent JWM, Caballero P, Herrero S. Iflavirus increases its infectivity and physical stability in association with baculovirus. PeerJ 2016; 4:e1687. [PMID: 26966651 PMCID: PMC4782719 DOI: 10.7717/peerj.1687] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 01/22/2016] [Indexed: 11/20/2022] Open
Abstract
Virus transmission and the prevalence of infection depend on multiple factors, including the interaction with other viral pathogens infecting the same host. In this study, active replication of an iflavirus, Spodoptera exigua iflavirus 1 (order Picornavirales) was observed in the offspring of insects that survived following inoculation with a pathogenic baculovirus, Spodoptera exigua multiple nucleopolyhedrovirus. Tracking the origin of the iflavirus suggested the association of this virus with the occlusion bodies of the baculovirus. Here we investigated the effect of this association on the stability and infectivity of both viruses. A reduction in baculovirus pathogenicity, without affecting its infectivity and productivity, was observed when associated with the iflavirus. In contrast, viral association increased the infectivity of the iflavirus and its resistance to ultraviolet radiation and high temperature, two of the main factors affecting virus stability in the field. In addition, electron microscopy analysis revealed the presence of particles resembling iflavirus virions inside the occlusion bodies of the baculovirus, suggesting the possible co-occlusion of both viruses. Results reported here are indicative of facultative phoresis of a virus and suggest that virus–virus interactions may be more common than currently recognized, and may be influential in the ecology of baculovirus and host populations and in consequence in the use of baculoviruses as biological insecticides.
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Affiliation(s)
- Agata K Jakubowska
- Department of Genetics, Universitat de València, Burjassot, Valencia, Spain; Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI-BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
| | - Rosa Murillo
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, Pamplona, Spain; Departamento de Producción Agraria, Universidad Pública de Navarra, Pamplona, Navarra, Spain
| | - Arkaitz Carballo
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, Pamplona, Spain; Departamento de Producción Agraria, Universidad Pública de Navarra, Pamplona, Navarra, Spain
| | | | - Jan W M van Lent
- Laboratory of Virology, Dept. of Plant Sciences, Wageningen Agricultural University , Wageningen , Netherlands
| | - Primitivo Caballero
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, Pamplona, Spain; Departamento de Producción Agraria, Universidad Pública de Navarra, Pamplona, Navarra, Spain
| | - Salvador Herrero
- Department of Genetics, Universitat de València, Burjassot, Valencia, Spain; Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI-BIOTECMED), Universitat de València, Burjassot, Valencia, Spain
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16
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Nouri S, Salem N, Nigg JC, Falk BW. Diverse Array of New Viral Sequences Identified in Worldwide Populations of the Asian Citrus Psyllid (Diaphorina citri) Using Viral Metagenomics. J Virol 2015; 90:2434-45. [PMID: 26676774 PMCID: PMC4810699 DOI: 10.1128/jvi.02793-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 12/08/2015] [Indexed: 12/26/2022] Open
Abstract
UNLABELLED The Asian citrus psyllid, Diaphorina citri, is the natural vector of the causal agent of Huanglongbing (HLB), or citrus greening disease. Together; HLB and D. citri represent a major threat to world citrus production. As there is no cure for HLB, insect vector management is considered one strategy to help control the disease, and D. citri viruses might be useful. In this study, we used a metagenomic approach to analyze viral sequences associated with the global population of D. citri. By sequencing small RNAs and the transcriptome coupled with bioinformatics analysis, we showed that the virus-like sequences of D. citri are diverse. We identified novel viral sequences belonging to the picornavirus superfamily, the Reoviridae, Parvoviridae, and Bunyaviridae families, and an unclassified positive-sense single-stranded RNA virus. Moreover, a Wolbachia prophage-related sequence was identified. This is the first comprehensive survey to assess the viral community from worldwide populations of an agricultural insect pest. Our results provide valuable information on new putative viruses, some of which may have the potential to be used as biocontrol agents. IMPORTANCE Insects have the most species of all animals, and are hosts to, and vectors of, a great variety of known and unknown viruses. Some of these most likely have the potential to be important fundamental and/or practical resources. In this study, we used high-throughput next-generation sequencing (NGS) technology and bioinformatics analysis to identify putative viruses associated with Diaphorina citri, the Asian citrus psyllid. D. citri is the vector of the bacterium causing Huanglongbing (HLB), currently the most serious threat to citrus worldwide. Here, we report several novel viral sequences associated with D. citri.
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Affiliation(s)
- Shahideh Nouri
- Department of Plant Pathology, University of California, Davis, California, USA
| | - Nidá Salem
- Department of Plant Protection, The University of Jordan, Amman, Jordan
| | - Jared C Nigg
- Department of Plant Pathology, University of California, Davis, California, USA
| | - Bryce W Falk
- Department of Plant Pathology, University of California, Davis, California, USA
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17
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Silva LA, Ardisson-Araujo DMP, Tinoco RS, Fernandes OA, Melo FL, Ribeiro BM. Complete genome sequence and structural characterization of a novel iflavirus isolated from Opsiphanes invirae (Lepidoptera: Nymphalidae). J Invertebr Pathol 2015; 130:136-40. [PMID: 26254043 DOI: 10.1016/j.jip.2015.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 07/31/2015] [Accepted: 08/03/2015] [Indexed: 10/23/2022]
Abstract
Opsiphanes invirae (Lepidopera: Nymphalidae) is a common pest of the African oil palm tree (Elaeis guineensis) in Brazil. Dead larvae were collected in canopy of oil palm trees cultivated in the amazon region (Para State) and analyzed for viral infection. Electron microscopy of caterpillar extracts showed an icosahedral picorna-like virus particle with 30nm in diameter. Total RNA extracted from partially purified virus particles was sequenced. A contig of 10,083 nucleotides (nt) was identified and showed to encode one single predicted polyprotein with 3185 amino acid residues. Phylogenetic analysis showed that the new virus was closely related to another lepidopteran infective virus Spodoptera exigua iflavirus 1(SeIV-1), with 35% amino acid pairwise identity. The novel virus fulfils all ICTV requirements for a new iflavirus species and was named Opsiphanes invirae Iflavirus 1 (OilV-1).
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Affiliation(s)
- Leonardo A Silva
- Cell Biology Department, University of Brasília, 70910-900 Brasília, DF, Brazil
| | | | - Ricardo S Tinoco
- Plant Protection and Research Manager of Group Agropalma S/A, 68695-000 Tailândia, PA, Brazil
| | - Odair A Fernandes
- UNESP - Univ Estadual Paulista, Departamento de Fitossanidade, Jaboticabal, SP 14884-900, Brazil
| | - Fernando L Melo
- Cell Biology Department, University of Brasília, 70910-900 Brasília, DF, Brazil
| | - Bergmann M Ribeiro
- Cell Biology Department, University of Brasília, 70910-900 Brasília, DF, Brazil.
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18
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Liu S, Chen Y, Bonning BC. RNA virus discovery in insects. CURRENT OPINION IN INSECT SCIENCE 2015; 8:54-61. [PMID: 32846679 DOI: 10.1016/j.cois.2014.12.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 12/05/2014] [Indexed: 06/11/2023]
Abstract
The advent of next generation sequencing (NGS) technology has allowed for significant advances in insect RNA virus discovery, particularly for identification of covert viruses and for identification of previously undescribed virus groups. Recent research has revealed the complexity and diversity both of viral populations within an insect, and of different virus groups infecting insects. While appropriate verification of the ability of a given virus to infect a putative host is essential, this is frequently challenging for newly discovered viruses. In this chapter, we describe recently discovered RNA viruses of insects, optimization of NGS data analysis for virus discovery, and challenges associated with virus nomenclature.
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Affiliation(s)
- Sijun Liu
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | - Yuting Chen
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - Bryony C Bonning
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
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19
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Carrillo-Tripp J, Krueger EN, Harrison RL, Toth AL, Miller WA, Bonning BC. Lymantria dispar iflavirus 1 (LdIV1), a new model to study iflaviral persistence in lepidopterans. J Gen Virol 2014; 95:2285-2296. [DOI: 10.1099/vir.0.067710-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The cell line IPLB-LD-652Y, derived from the gypsy moth (Lymantria dispar L.), is routinely used to study interactions between viruses and insect hosts. Here we report the full genome sequence and biological characteristics of a small RNA virus, designated Lymantria dispar iflavirus 1 (LdIV1), that was discovered to persistently infect IPLB-LD-652Y. LdIV1 belongs to the genus Iflavirus. LdIV1 formed icosahedral particles of approx. 30 nm in diameter and contained a 10 044 nt polyadenylated, positive-sense RNA genome encoding a predicted polyprotein of 2980 aa. LdIV1 was induced by a viral suppressor of RNA silencing, suggesting that acute infection is restricted by RNA interference (RNAi). We detected LdIV1 in all tested tissues of gypsy-moth larvae and adults, but the virus was absent from other L. dispar-derived cell lines. We confirmed LdIV1 infectivity in two of these cell lines (IPLB-LD-652 and IPLB-LdFB). Our results provide a novel system to explore persistent infections in lepidopterans and a new model for the study of iflaviruses, a rapidly expanding group of viruses, many of which covertly infect their hosts.
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Affiliation(s)
- Jimena Carrillo-Tripp
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Elizabeth N. Krueger
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Robert L. Harrison
- Invasive Insect Biocontrol and Behavior Laboratory, USDA Agricultural Research Service, Beltsville, MD 20705, USA
| | - Amy L. Toth
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
| | - W. Allen Miller
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Bryony C. Bonning
- Department of Entomology, Iowa State University, Ames, IA 50011, USA
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20
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Virto C, Navarro D, Tellez MM, Herrero S, Williams T, Murillo R, Caballero P. Natural populations of Spodoptera exigua are infected by multiple viruses that are transmitted to their offspring. J Invertebr Pathol 2014; 122:22-7. [DOI: 10.1016/j.jip.2014.07.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/28/2014] [Accepted: 07/29/2014] [Indexed: 02/06/2023]
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21
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Jakubowska AK, D'Angiolo M, González-Martínez RM, Millán-Leiva A, Carballo A, Murillo R, Caballero P, Herrero S. Simultaneous occurrence of covert infections with small RNA viruses in the lepidopteran Spodoptera exigua. J Invertebr Pathol 2014; 121:56-63. [PMID: 24997384 DOI: 10.1016/j.jip.2014.06.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/12/2014] [Accepted: 06/24/2014] [Indexed: 12/21/2022]
Abstract
Viral covert infections in invertebrates have been traditionally attributed to sublethal infections that were not able to establish an acute infection. Recent studies are revealing that, although true for some viruses, other viruses may follow the strategy of establishing covert or persistent infections without producing the death of the host. Recently, and due to the revolution in the sequencing technologies, a large number of viruses causing covert infections in all type of hosts have been identified. The beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae) is a worldwide pest that causes significant losses to agricultural and ornamental plant industries. In a previous project we used NGS to obtain a comprehensive transcriptome of the larval stage, revealing the presence of an important number of unigenes belonging to novel RNA viruses, most of them from the order Picornavirales. In order to characterize S. exigua viral complex, in this work we have completed the genomic sequences of two picorna-like viruses, and compared them to a SeIV1, a member of Iflaviridae previously described by our group. We performed additional studies to determine virus morphology, horizontal transmission, tissue and life stage distribution and abundance in the hosts. We discuss the role of virus persistent infections on insect populations.
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Affiliation(s)
- Agata K Jakubowska
- Department of Genetics, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Spain.
| | - Melania D'Angiolo
- Department of Genetics, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Spain
| | | | - Anabel Millán-Leiva
- Department of Genetics, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Spain
| | - Arkaitz Carballo
- Instituto de Agrobiotecnología, CSIC-UPNa-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain
| | - Rosa Murillo
- Instituto de Agrobiotecnología, CSIC-UPNa-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain
| | - Primitivo Caballero
- Instituto de Agrobiotecnología, CSIC-UPNa-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain
| | - Salvador Herrero
- Department of Genetics, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Spain
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22
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Geng P, Li W, Lin L, de Miranda JR, Emrich S, An L, Terenius O. Genetic characterization of a novel Iflavirus associated with vomiting disease in the Chinese oak silkmoth Antheraea pernyi. PLoS One 2014; 9:e92107. [PMID: 24637949 PMCID: PMC3956879 DOI: 10.1371/journal.pone.0092107] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 02/18/2014] [Indexed: 02/07/2023] Open
Abstract
Larvae of the Chinese oak silkmoth (Antheraea pernyi) are often affected by AVD (A. pernyi vomiting disease), whose causative agent has long been suspected to be a virus. In an unrelated project we discovered a novel positive sense single-stranded RNA virus that could reproduce AVD symptoms upon injection into healthy A. pernyi larvae. The genome of this virus is 10,163 nucleotides long, has a natural poly-A tail, and contains a single, large open reading frame flanked at the 5′ and 3′ ends by untranslated regions containing putative structural elements for replication and translation of the virus genome. The open reading frame is predicted to encode a 3036 amino acid polyprotein with four viral structural proteins (VP1-VP4) located in the N-terminal end and the non-structural proteins, including a helicase, RNA-dependent RNA polymerase and 3C-protease, located in the C-terminal end of the polyprotein. Putative 3C-protease and autolytic cleavage sites were identified for processing the polyprotein into functional units. The genome organization, amino acid sequence and phylogenetic analyses suggest that the virus is a novel species of the genus Iflavirus, with the proposed name of Antheraea pernyi Iflavirus (ApIV).
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Affiliation(s)
- Peng Geng
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, People's Republic of China
| | - Wenli Li
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, People's Republic of China
| | - Lan Lin
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, People's Republic of China
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, People's Republic of China
| | - Joachim R. de Miranda
- Department of Ecology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Scott Emrich
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Lijia An
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, People's Republic of China
| | - Olle Terenius
- Department of Ecology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
- * E-mail:
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23
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Pascual L, Jakubowska AK, Blanca JM, Cañizares J, Ferré J, Gloeckner G, Vogel H, Herrero S. The transcriptome of Spodoptera exigua larvae exposed to different types of microbes. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 42:557-570. [PMID: 22564783 DOI: 10.1016/j.ibmb.2012.04.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 04/04/2012] [Accepted: 04/07/2012] [Indexed: 05/31/2023]
Abstract
We have obtained and characterized the transcriptome of Spodoptera exigua larvae with special emphasis on pathogen-induced genes. In order to obtain a highly representative transcriptome, we have pooled RNA from diverse insect colonies, conditions and tissues. Sequenced cDNA included samples from 3 geographically different colonies. Enrichment of RNA from pathogen-related genes was accomplished by exposing larvae to different pathogenic and non-pathogenic microbial agents such as the bacteria Bacillus thuringiensis, Micrococcus luteus, and Escherichia coli, the yeast Saccharomyces cerevisiae, and the S. exigua nucleopolyhedrovirus (SeMNPV). In addition, to avoid the loss of tissue-specific genes we included cDNA from the midgut, fat body, hemocytes and integument derived from pathogen exposed insects. RNA obtained from the different types of samples was pooled, normalized and sequenced. Analysis of the sequences obtained using the Roche 454 FLX and Sanger methods has allowed the generation of the largest public set of ESTs from S. exigua, including a large group of immune genes, and the identification of an important number of SSR (simple sequence repeats) and SNVs (single nucleotide variants: SNPs and INDELs) with potential use as genetic markers. Moreover, data mining has allowed the discovery of novel RNA viruses with potential influence in the insect population dynamics and the larval interactions with the microbial pesticides that are currently in use for the biological control of this pest.
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Affiliation(s)
- Laura Pascual
- Instituto de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV), Universidad Politécnica de Valencia, Camino de Vera s/n, Valencia, Spain
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