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Roberts JMK, Simbiken N, Dale C, Armstrong J, Anderson DL. Tolerance of Honey Bees to Varroa Mite in the Absence of Deformed Wing Virus. Viruses 2020; 12:E575. [PMID: 32456246 PMCID: PMC7290856 DOI: 10.3390/v12050575] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/31/2022] Open
Abstract
The global spread of the parasitic mite Varroa destructor has emphasized the significance of viruses as pathogens of honey bee (Apis mellifera) populations. In particular, the association of deformed wing virus (DWV) with V. destructor and its devastating effect on honey bee colonies has led to that virus now becoming one of the most well-studied insect viruses. However, there has been no opportunity to examine the effects of Varroa mites without the influence of DWV. In Papua New Guinea (PNG), the sister species, V. jacobsoni, has emerged through a host-shift to reproduce on the local A. mellifera population. After initial colony losses, beekeepers have maintained colonies without chemicals for more than a decade, suggesting that this bee population has an unknown mite tolerance mechanism. Using high throughput sequencing (HTS) and target PCR detection, we investigated whether the viral landscape of the PNG honey bee population is the underlying factor responsible for mite tolerance. We found A. mellifera and A. cerana from PNG and nearby Solomon Islands were predominantly infected by sacbrood virus (SBV), black queen cell virus (BQCV) and Lake Sinai viruses (LSV), with no evidence for any DWV strains. V. jacobsoni was infected by several viral homologs to recently discovered V. destructor viruses, but Varroa jacobsoni rhabdovirus-1 (ARV-1 homolog) was the only virus detected in both mites and honey bees. We conclude from these findings that A. mellifera in PNG may tolerate V. jacobsoni because the damage from parasitism is significantly reduced without DWV. This study also provides further evidence that DWV does not exist as a covert infection in all honey bee populations, and remaining free of this serious viral pathogen can have important implications for bee health outcomes in the face of Varroa.
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Affiliation(s)
- John M. K. Roberts
- Commonwealth Scientific and Industrial Research Organisation, Canberra 2601, Australia;
| | - Nelson Simbiken
- Coffee Industry Corporation Ltd., Goroka 441, Papua New Guinea;
| | - Chris Dale
- Department of Agriculture, Water and the Environment, Canberra 2601, Australia;
| | - Joel Armstrong
- Commonwealth Scientific and Industrial Research Organisation, Canberra 2601, Australia;
| | - Denis L. Anderson
- Research and Development Division, Abu Dhabi Agriculture & Food Safety Authority, Al Ain, UAE;
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102
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Varroa destructor: A Complex Parasite, Crippling Honey Bees Worldwide. Trends Parasitol 2020; 36:592-606. [PMID: 32456963 DOI: 10.1016/j.pt.2020.04.004] [Citation(s) in RCA: 155] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/24/2020] [Accepted: 04/09/2020] [Indexed: 11/20/2022]
Abstract
The parasitic mite, Varroa destructor, has shaken the beekeeping and pollination industries since its spread from its native host, the Asian honey bee (Apis cerana), to the naïve European honey bee (Apis mellifera) used commercially for pollination and honey production around the globe. Varroa is the greatest threat to honey bee health. Worrying observations include increasing acaricide resistance in the varroa population and sinking economic treatment thresholds, suggesting that the mites or their vectored viruses are becoming more virulent. Highly infested weak colonies facilitate mite dispersal and disease transmission to stronger and healthier colonies. Here, we review recent developments in the biology, pathology, and management of varroa, and integrate older knowledge that is less well known.
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103
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Al Naggar Y, Paxton RJ. Mode of Transmission Determines the Virulence of Black Queen Cell Virus in Adult Honey Bees, Posing a Future Threat to Bees and Apiculture. Viruses 2020; 12:E535. [PMID: 32422881 PMCID: PMC7290678 DOI: 10.3390/v12050535] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/03/2020] [Accepted: 05/12/2020] [Indexed: 12/15/2022] Open
Abstract
Honey bees (Apis mellifera) can be infected by many viruses, some of which pose a major threat to their health and well-being. A critical step in the dynamics of a viral infection is its mode of transmission. Here, we compared for the first time the effect of mode of horizontal transmission of Black queen cell virus (BQCV), a ubiquitous and highly prevalent virus of A. mellifera, on viral virulence in individual adult honey bees. Hosts were exposed to BQCV either by feeding (representing direct transmission) or by injection into hemolymph (analogous to indirect or vector-mediated transmission) through a controlled laboratory experimental design. Mortality, viral titer and expression of three key innate immune-related genes were then quantified. Injecting BQCV directly into hemolymph in the hemocoel resulted in far higher mortality as well as increased viral titer and significant change in the expression of key components of the RNAi pathway compared to feeding honey bees BQCV. Our results support the hypothesis that mode of horizontal transmission determines BQCV virulence in honey bees. BQCV is currently considered a benign viral pathogen of adult honey bees, possibly because its mode of horizontal transmission is primarily direct, per os. We anticipate adverse health effects on honey bees if BQCV transmission becomes vector-mediated.
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Affiliation(s)
- Yahya Al Naggar
- General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany;
- Zoology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt
| | - Robert J. Paxton
- General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany;
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104
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Coulon M, Dalmon A, Di Prisco G, Prado A, Arban F, Dubois E, Ribière-Chabert M, Alaux C, Thiéry R, Le Conte Y. Interactions Between Thiamethoxam and Deformed Wing Virus Can Drastically Impair Flight Behavior of Honey Bees. Front Microbiol 2020; 11:766. [PMID: 32425910 PMCID: PMC7203464 DOI: 10.3389/fmicb.2020.00766] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/31/2020] [Indexed: 01/06/2023] Open
Abstract
Exposure to multiple stress factors is believed to contribute to honey bee colony decline. However, little is known about how co-exposure to stress factors can alter the survival and behavior of free-living honey bees in colony conditions. We therefore studied the potential interaction between a neonicotinoid pesticide, thiamethoxam, and a highly prevalent honey bee pathogen, Deformed wing virus (DWV). For this purpose, tagged bees were exposed to DWV by feeding or injection, and/or to field-relevant doses of thiamethoxam, then left in colonies equipped with optical bee counters to monitor flight activity. DWV loads and the expression of immune genes were quantified. A reduction in vitellogenin expression level was observed in DWV-injected bees and was associated with precocious onset of foraging. Combined exposure to DWV and thiamethoxam did not result in higher DWV loads compared to bees only exposed to DWV, but induced precocious foraging, increased the risk of not returning to the hive after the first flight, and decreased survival when compared to single stress exposures. We therefore provided the first evidence for deleterious interactions between DWV and thiamethoxam in natural conditions.
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Affiliation(s)
- Marianne Coulon
- INRAE, UR 406 Abeilles et Environnement, Site Agroparc, Avignon, France.,ANSES Sophia Antipolis, Unit of Honey bee Pathology, Sophia Antipolis, France
| | - Anne Dalmon
- INRAE, UR 406 Abeilles et Environnement, Site Agroparc, Avignon, France
| | - Gennaro Di Prisco
- CREA-AA, Research Centre for Agriculture and Environment, Council for Agricultural Research and Economics, Bologna, Italy.,Department of Agriculture, University of Naples "Federico II", Portici, Italy
| | - Alberto Prado
- INRAE, UR 406 Abeilles et Environnement, Site Agroparc, Avignon, France.,Escuela Nacional de Estudios Superiores Juriquilla, UNAM, Juriquilla, Mexico
| | - Florine Arban
- INRAE, UR 406 Abeilles et Environnement, Site Agroparc, Avignon, France
| | - Eric Dubois
- ANSES Sophia Antipolis, Unit of Honey bee Pathology, Sophia Antipolis, France
| | | | - Cedric Alaux
- INRAE, UR 406 Abeilles et Environnement, Site Agroparc, Avignon, France
| | - Richard Thiéry
- ANSES Sophia Antipolis, Unit of Honey bee Pathology, Sophia Antipolis, France
| | - Yves Le Conte
- INRAE, UR 406 Abeilles et Environnement, Site Agroparc, Avignon, France
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105
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Beaurepaire A, Piot N, Doublet V, Antunez K, Campbell E, Chantawannakul P, Chejanovsky N, Gajda A, Heerman M, Panziera D, Smagghe G, Yañez O, de Miranda JR, Dalmon A. Diversity and Global Distribution of Viruses of the Western Honey Bee, Apis mellifera. INSECTS 2020; 11:E239. [PMID: 32290327 PMCID: PMC7240362 DOI: 10.3390/insects11040239] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 12/31/2022]
Abstract
In the past centuries, viruses have benefited from globalization to spread across the globe, infecting new host species and populations. A growing number of viruses have been documented in the western honey bee, Apis mellifera. Several of these contribute significantly to honey bee colony losses. This review synthetizes the knowledge of the diversity and distribution of honey-bee-infecting viruses, including recent data from high-throughput sequencing (HTS). After presenting the diversity of viruses and their corresponding symptoms, we surveyed the scientific literature for the prevalence of these pathogens across the globe. The geographical distribution shows that the most prevalent viruses (deformed wing virus, sacbrood virus, black queen cell virus and acute paralysis complex) are also the most widely distributed. We discuss the ecological drivers that influence the distribution of these pathogens in worldwide honey bee populations. Besides the natural transmission routes and the resulting temporal dynamics, global trade contributes to their dissemination. As recent evidence shows that these viruses are often multihost pathogens, their spread is a risk for both the beekeeping industry and the pollination services provided by managed and wild pollinators.
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Affiliation(s)
- Alexis Beaurepaire
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3003 Bern, Switzerland;
- Agroscope, Swiss Bee Research Center, 3003 Bern, Switzerland
- UR Abeilles et Environnement, INRAE, 84914 Avignon, France;
| | - Niels Piot
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium; (N.P.); (G.S.)
| | - Vincent Doublet
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, 86069 Ulm, Germany;
| | - Karina Antunez
- Department of Microbiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay;
| | - Ewan Campbell
- Centre for Genome Enabled Biology and Medicine, University of Aberdeen, Aberdeen AB24 3FX, UK;
| | - Panuwan Chantawannakul
- Environmental Science Research Center (ESRC), Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand;
- Bee Protection Laboratory (BeeP), Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Nor Chejanovsky
- Entomology Department, Institute of Plant Protection, The Volcani Center, Rishon Lezion, Tel Aviv 5025001, Israel;
| | - Anna Gajda
- Laboratory of Bee Diseases, Institute of Veterinary Medicine, Warsaw University of Life Sciences, 02-787 Warsaw, Poland;
| | | | - Delphine Panziera
- Institute of Biology, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany;
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany
| | - Guy Smagghe
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium; (N.P.); (G.S.)
| | - Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3003 Bern, Switzerland;
- Agroscope, Swiss Bee Research Center, 3003 Bern, Switzerland
| | - Joachim R. de Miranda
- Department of Ecology, Swedish University of Agricultural Sciences, 750-07 Uppsala, Sweden;
| | - Anne Dalmon
- UR Abeilles et Environnement, INRAE, 84914 Avignon, France;
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106
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Norton AM, Remnant EJ, Buchmann G, Beekman M. Accumulation and Competition Amongst Deformed Wing Virus Genotypes in Naïve Australian Honeybees Provides Insight Into the Increasing Global Prevalence of Genotype B. Front Microbiol 2020; 11:620. [PMID: 32328051 PMCID: PMC7160646 DOI: 10.3389/fmicb.2020.00620] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/19/2020] [Indexed: 12/27/2022] Open
Abstract
Honeybee colony deaths are often attributed to the ectoparasitic mite Varroa destructor and deformed wing virus (DWV), vectored by the mite. In the presence of V. destructor both main genotypes (DWV-A and DWV-B) have been correlated with colony loss. Studies show that DWV-B is the most prevalent genotype in the United Kingdom and Europe. More recently DWV-B has increased in prevalence in the United States. The increasing prevalence of DWV-B at the expense of DWV-A suggests that competition exists between the genotypes. Competition may be due to disparities in virulence between genotypes, differences in fitness, such as rate of replication, or a combination of factors. In this study we investigated if DWV genotypes differ in their rate of accumulation in Australian honeybees naïve to both V. destructor and DWV, and if viral load was associated with mortality in honeybee pupae. We singly and co-infected pupae with DWV-A, DWV-B, and a recombinant strain isolated from a V. destructor tolerant bee population. We monitored viral accumulation throughout pupation, up to 192 h post-injection. We found significant differences in accumulation, where DWV-A accumulated to significantly lower loads than DWV-B and the DWV-recombinant. We also found evidence of competition, where DWV-B loads were significantly reduced in the presence of DWV-A, but still accumulated to the highest loads overall. In contrast to previous studies, we found significant differences in virulence between pupae injected with DWV-A and DWV-B. The average mortality associated with DWV-B (0.4% ± 0.33 SE) and DWV-recombinant (2.2% ± 0.83 SE) injection were significantly less than observed for DWV-A (11% ± 1.2 SE). Our results suggest that a higher proportion of DWV-B infected pupae will emerge into adults, compared to DWV-A. Overall, our data suggest that low mortality in pupae and the ability of DWV-B to accumulate to higher loads relative to DWV-A even during co-infection may favor vector transmission by V. destructor, and may thus be contributing factors to the increasing prevalence of DWV-B globally.
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Affiliation(s)
- Amanda M. Norton
- Behaviour, Ecology and Evolution (BEE) Laboratory, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
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107
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Yañez O, Chávez-Galarza J, Tellgren-Roth C, Pinto MA, Neumann P, de Miranda JR. The honeybee (Apis mellifera) developmental state shapes the genetic composition of the deformed wing virus-A quasispecies during serial transmission. Sci Rep 2020; 10:5956. [PMID: 32249797 PMCID: PMC7136270 DOI: 10.1038/s41598-020-62673-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 03/17/2020] [Indexed: 11/23/2022] Open
Abstract
The main biological threat to the western honeybee (Apis mellifera) is the parasitic mite Varroa destructor, largely because it vectors lethal epidemics of honeybee viruses that, in the absence of this mite, are relatively innocuous. The severe pathology is a direct consequence of excessive virus titres caused by this novel transmission route. However, little is known about how the virus adapts genetically during transmission and whether this influences the pathology. Here, we show that upon injection into honeybee pupae, the deformed wing virus type-A (DWV-A) quasispecies undergoes a rapid, extensive expansion of its sequence space, followed by strong negative selection towards a uniform, common shape by the time the pupae have completed their development, with no difference between symptomatic and asymptomatic adults in either DWV titre or genetic composition. This suggests that the physiological and molecular environment during pupal development has a strong, conservative influence on shaping the DWV-A quasispecies in emerging adults. There was furthermore no evidence of any progressive adaptation of the DWV-A quasispecies to serial intra-abdominal injection, simulating mite transmission, despite the generation of ample variation immediately following each transmission, suggesting that the virus either had already adapted to transmission by injection, or was unaffected by it.
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Affiliation(s)
- Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, CH-3000, Switzerland
| | - Julio Chávez-Galarza
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Sta. Apolónia, 5300-253, Bragança, Portugal
- Instituto Nacional de Innovación Agraria (INIA), Av. La Molina, 1981, Lima, Perú
| | | | - M Alice Pinto
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Sta. Apolónia, 5300-253, Bragança, Portugal
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, CH-3000, Switzerland
| | - Joachim R de Miranda
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, 750 07, Sweden.
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108
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Ottati S, Persico A, Rossi M, Bosco D, Vallino M, Abbà S, Molinatto G, Palmano S, Balestrini R, Galetto L, Marzachì C. Biological characterization of Euscelidius variegatus iflavirus 1. J Invertebr Pathol 2020; 173:107370. [PMID: 32259537 DOI: 10.1016/j.jip.2020.107370] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 03/25/2020] [Accepted: 03/26/2020] [Indexed: 11/16/2022]
Abstract
Virus-based biocontrol technologies represent sustainable alternatives to pesticides and insecticides. Phytoplasmas are prokaryotic plant pathogens causing severe losses to crops worldwide. Novel approaches are needed since insecticides against their insect vectors and rogueing of infected plants are the only available strategies to counteract phytoplasma diseases. A new iflavirus, named EVV-1, has been described in the leafhopper phytoplasma vector Euscelidius variegatus, raising the potential to use virus-based application strategies against phytoplasma disease. Here transmission routes of EVV-1 are characterized, and localization within the host reveals the mechanism of insect tolerance to virus infection. Both vertical and horizontal transmission of EVV-1 occur and vertical transmission was more efficient. The virus is systemic and occurs in all life-stages, with the highest loads measured in ovaries and first to third instar nymphs. The basic knowledge gained here on the biology of the virus is crucial for possible future application of iflaviruses as biocontrol agents.
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Affiliation(s)
- Sara Ottati
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy; Dipartimento di Scienze Agrarie, Forestali ed Alimentari DISAFA, Università degli Studi di Torino, Largo Paolo Braccini 2, 10095 Grugliasco (TO), Italy.
| | - Alberto Persico
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy; Dipartimento di Scienze Agrarie, Forestali ed Alimentari DISAFA, Università degli Studi di Torino, Largo Paolo Braccini 2, 10095 Grugliasco (TO), Italy
| | - Marika Rossi
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy.
| | - Domenico Bosco
- Dipartimento di Scienze Agrarie, Forestali ed Alimentari DISAFA, Università degli Studi di Torino, Largo Paolo Braccini 2, 10095 Grugliasco (TO), Italy.
| | - Marta Vallino
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy.
| | - Simona Abbà
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy.
| | - Giulia Molinatto
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy; Dipartimento di Scienze Agrarie, Forestali ed Alimentari DISAFA, Università degli Studi di Torino, Largo Paolo Braccini 2, 10095 Grugliasco (TO), Italy.
| | - Sabrina Palmano
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy.
| | - Raffaella Balestrini
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy.
| | - Luciana Galetto
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy.
| | - Cristina Marzachì
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, IPSP-CNR, Strada delle Cacce 73 10135, Torino, Italy.
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109
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Ryabov EV, Christmon K, Heerman MC, Posada-Florez F, Harrison RL, Chen Y, Evans JD. Development of a Honey Bee RNA Virus Vector Based on the Genome of a Deformed Wing Virus. Viruses 2020; 12:E374. [PMID: 32231059 PMCID: PMC7232236 DOI: 10.3390/v12040374] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/24/2020] [Accepted: 03/26/2020] [Indexed: 12/22/2022] Open
Abstract
We developed a honey bee RNA-virus vector based on the genome of a picorna-like Deformed wing virus (DWV), the main viral pathogen of the honey bee (Apis mellifera). To test the potential of DWV to be utilized as a vector, the 717 nt sequence coding for the enhanced green fluorescent protein (eGFP), flanked by the peptides targeted by viral protease, was inserted into an infectious cDNA clone of DWV in-frame between the leader protein and the virus structural protein VP2 genes. The in vitro RNA transcripts from egfp-tagged DWV cDNA clones were infectious when injected into honey bee pupae. Stable DWV particles containing genomic RNA of the recovered DWV with egfp inserts were produced, as evidenced by cesium chloride density gradient centrifugation. These particles were infectious to honey bee pupae when injected intra-abdominally. Fluorescent microscopy showed GFP expression in the infected cells and Western blot analysis demonstrated accumulation of free eGFP rather than its fusions with DWV leader protein (LP) and/or viral protein (VP) 2. Analysis of the progeny egfp-tagged DWV showed gradual accumulation of genome deletions for egfp, providing estimates for the rate of loss of a non-essential gene an insect RNA virus genome during natural infection.
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Affiliation(s)
- Eugene V. Ryabov
- USDA, Agricultural Research Service, Bee Research Lab, Beltsville, MD 20705, USA; (K.C.); (M.C.H.); (F.P.-F.); (Y.C.); (J.D.E.)
| | - Krisztina Christmon
- USDA, Agricultural Research Service, Bee Research Lab, Beltsville, MD 20705, USA; (K.C.); (M.C.H.); (F.P.-F.); (Y.C.); (J.D.E.)
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
| | - Matthew C. Heerman
- USDA, Agricultural Research Service, Bee Research Lab, Beltsville, MD 20705, USA; (K.C.); (M.C.H.); (F.P.-F.); (Y.C.); (J.D.E.)
| | - Francisco Posada-Florez
- USDA, Agricultural Research Service, Bee Research Lab, Beltsville, MD 20705, USA; (K.C.); (M.C.H.); (F.P.-F.); (Y.C.); (J.D.E.)
| | - Robert L. Harrison
- USDA, Agricultural Research Service, Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, MD 20705, USA;
| | - Yanping Chen
- USDA, Agricultural Research Service, Bee Research Lab, Beltsville, MD 20705, USA; (K.C.); (M.C.H.); (F.P.-F.); (Y.C.); (J.D.E.)
| | - Jay D. Evans
- USDA, Agricultural Research Service, Bee Research Lab, Beltsville, MD 20705, USA; (K.C.); (M.C.H.); (F.P.-F.); (Y.C.); (J.D.E.)
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110
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Dobelmann J, Felden A, Lester PJ. Genetic Strain Diversity of Multi-Host RNA Viruses that Infect a Wide Range of Pollinators and Associates is Shaped by Geographic Origins. Viruses 2020; 12:E358. [PMID: 32213950 PMCID: PMC7150836 DOI: 10.3390/v12030358] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 03/16/2020] [Accepted: 03/21/2020] [Indexed: 01/29/2023] Open
Abstract
Emerging viruses have caused concerns about pollinator population declines, as multi-host RNA viruses may pose a health threat to pollinators and associated arthropods. In order to understand the ecology and impact these viruses have, we studied their host range and determined to what extent host and spatial variation affect strain diversity. Firstly, we used RT-PCR to screen pollinators and associates, including honey bees (Apis mellifera) and invasive Argentine ants (Linepithema humile), for virus presence and replication. We tested for the black queen cell virus (BQCV), deformed wing virus (DWV), and Kashmir bee virus (KBV) that were initially detected in bees, and the two recently discovered Linepithema humile bunya-like virus 1 (LhuBLV1) and Moku virus (MKV). DWV, KBV, and MKV were detected and replicated in a wide range of hosts and commonly co-infected hymenopterans. Secondly, we placed KBV and DWV in a global phylogeny with sequences from various countries and hosts to determine the association of geographic origin and host with shared ancestry. Both phylogenies showed strong geographic rather than host-specific clustering, suggesting frequent inter-species virus transmission. Transmission routes between hosts are largely unknown. Nonetheless, avoiding the introduction of non-native species and diseased pollinators appears important to limit spill overs and disease emergence.
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Affiliation(s)
- Jana Dobelmann
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand; (A.F.); (P.J.L.)
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111
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Huwiler M, Papach A, Cristina E, Yañez O, Williams GR, Neumann P. Deformed wings of small hive beetle independent of virus infections and mites. J Invertebr Pathol 2020; 172:107365. [PMID: 32201240 DOI: 10.1016/j.jip.2020.107365] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 10/24/2022]
Abstract
Insect wing deformities can be caused by viruses, mites and other environmental stressors during development. Here we conducted differential diagnostics of deformed wings in small hive beetles, Aethina tumida (SHB). Adult SHB with and without deformed wings from individual and mass reared scenarios were evaluated for the mite Tyrophagus putrescentiae and for deformed wing virus. Viral load and mite number were similar for SHB with deformed wings and unaffected beetles. Because deformed wings were only observed in individually pupating SHB, a humidity challenge most likely explains the observed clinical symptoms. Our observations support the importance of differential diagnostics.
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Affiliation(s)
- Meret Huwiler
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Switzerland
| | - Anna Papach
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Switzerland.
| | - Elodie Cristina
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Switzerland
| | - Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Switzerland
| | - Geoffrey R Williams
- Department of Entomology & Plant Pathology, Auburn University, Auburn, AL, USA
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Switzerland; Agroscope, Swiss Bee Research Centre, Bern, Switzerland
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112
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Schläppi D, Chejanovsky N, Yañez O, Neumann P. Foodborne Transmission and Clinical Symptoms of Honey Bee Viruses in Ants Lasius spp. Viruses 2020; 12:E321. [PMID: 32192027 PMCID: PMC7150850 DOI: 10.3390/v12030321] [Citation(s) in RCA: 12] [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: 02/25/2020] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 01/10/2023] Open
Abstract
Emerging infectious diseases are often the products of host shifts, where a pathogen jumps from its original host to a novel species. Viruses in particular cross species barriers frequently. Acute bee paralysis virus (ABPV) and deformed wing virus (DWV) are viruses described in honey bees (Apis mellifera) with broad host ranges. Ants scavenging on dead honey bees may get infected with these viruses via foodborne transmission. However, the role of black garden ants, Lasius niger and Lasius platythorax, as alternative hosts of ABPV and DWV is not known and potential impacts of these viruses have not been addressed yet. In a laboratory feeding experiment, we show that L. niger can carry DWV and ABPV. However, negative-sense strand RNA, a token of virus replication, was only detected for ABPV. Therefore, additional L. niger colonies were tested for clinical symptoms of ABPV infections. Symptoms were detected at colony (fewer emerging workers) and individual level (impaired locomotion and movement speed). In a field survey, all L. platythorax samples carried ABPV, DWV-A and -B, as well as the negative-sense strand RNA of ABPV. These results show that L. niger and L. platythorax are alternative hosts of ABPV, possibly acting as a biological vector of ABPV and as a mechanical one for DWV. This is the first study showing the impact of honey bee viruses on ants. The common virus infections of ants in the field support possible negative consequences for ecosystem functioning due to host shifts.
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Affiliation(s)
- Daniel Schläppi
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (N.C.); (O.Y.); (P.N.)
| | - Nor Chejanovsky
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (N.C.); (O.Y.); (P.N.)
- Department of Entomology, Agricultural Research Organization, Volcani Center, 50250 Bet Dagan, Israel
| | - Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (N.C.); (O.Y.); (P.N.)
- Swiss Bee Research Centre, Agroscope, 3097 Bern, Switzerland
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (N.C.); (O.Y.); (P.N.)
- Swiss Bee Research Centre, Agroscope, 3097 Bern, Switzerland
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113
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Grozinger CM, Zayed A. Improving bee health through genomics. Nat Rev Genet 2020; 21:277-291. [DOI: 10.1038/s41576-020-0216-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2020] [Indexed: 01/16/2023]
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114
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Affiliation(s)
- Robert J. Paxton
- Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
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115
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Shi SL, Xia RX. Codon Usage in the Iflaviridae Family Is Not Diverse Though the Family Members Are Isolated from Diverse Host Taxa. Viruses 2019; 11:E1087. [PMID: 31766648 PMCID: PMC6950266 DOI: 10.3390/v11121087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 11/17/2019] [Accepted: 11/20/2019] [Indexed: 12/12/2022] Open
Abstract
All iflavirus members belong to the unique genus, Iflavirus, of the family, Iflaviridae. The host taxa and sequence identities of these viruses are diverse. A codon usage bias, maintained by a balance between selection, mutation, and genetic drift, exists in a wide variety of organisms. We characterized the codon usage patterns of 44 iflavirus genomes that were isolated from the classes, Insecta, Arachnida, Mammalia, and Malacostraca. Iflaviruses lack a strong codon usage bias when they are evaluated using an effective number of codons. The odds ratios of the majority of dinucleotides are within the normal range. However, the dinucleotides at the 1st-2nd codon positions are more biased than those at the 2nd-3rd codon positions. Plots of effective numbers of codons, relative neutrality analysis, and PR2 bias analysis all indicate that selection pressure dominates mutations in shaping codon usage patterns in the family, Iflaviridae. When these viruses were grouped into their host taxa, we found that the indices, including the nucleotide composition, effective number of codons, relative synonymous codon usage, and the influencing factors behind the codon usage patterns, all show that there are non-significant differences between the six host-taxa-groups. Our results disagree with our assumption that diverse viruses should possess diverse codon usage patterns, suggesting that the nucleotide composition and codon usage in the family, Iflaviridae, are not host taxa-specific signatures.
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Affiliation(s)
| | - Run-Xi Xia
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China;
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116
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Schläppi D, Lattrell P, Yañez O, Chejanovsky N, Neumann P. Foodborne Transmission of Deformed Wing Virus to Ants ( Myrmica rubra). INSECTS 2019; 10:E394. [PMID: 31703426 PMCID: PMC6920936 DOI: 10.3390/insects10110394] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/28/2019] [Accepted: 11/05/2019] [Indexed: 11/17/2022]
Abstract
Virus host shifts occur frequently, but the whole range of host species and the actual transmission pathways are often poorly understood. Deformed wing virus (DWV), an RNA virus described from honeybees (Apis mellifera), has been shown to have a broad host range. Since ants are often scavenging on dead honeybees, foodborne transmission of these viruses may occur. However, the role of the ant Myrmica rubra as an alternative host is not known and foodborne transmission to ants has not been experimentally addressed yet. Here, we show with a 16-week feeding experiment that foodborne transmission enables DWV type-A and -B to infect M. rubra and that these ants may serve as a virus reservoir. However, the titers of both plus- and minus-sense viral RNA strands decreased over time. Since the ants were fed with highly virus-saturated honeybee pupae, this probably resulted in initial viral peaks, then approaching lower equilibrium titers in infected individuals later. Since DWV infections were also found in untreated field-collected M. rubra colonies, our results support the wide host range of DWV and further suggest foodborne transmission as a so far underestimated spread mechanism.
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Affiliation(s)
- Daniel Schläppi
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (P.L.); (O.Y.); (N.C.); (P.N.)
| | - Patrick Lattrell
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (P.L.); (O.Y.); (N.C.); (P.N.)
| | - Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (P.L.); (O.Y.); (N.C.); (P.N.)
| | - Nor Chejanovsky
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (P.L.); (O.Y.); (N.C.); (P.N.)
- Department of Entomology, Agricultural Research Organization, the Volcani Center, Bet Dagan 50250, Israel
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3097 Bern, Switzerland; (P.L.); (O.Y.); (N.C.); (P.N.)
- Swiss Bee Research Centre, Agroscope, 3097 Bern, Switzerland
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117
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Tapia-González JM, Morfin N, Macías-Macías JO, De la Mora A, Tapia-Rivera JC, Ayala R, Contreras-Escareño F, Gashout HA, Guzman-Novoa E. Evidence of presence and replication of honey bee viruses among wild bee pollinators in subtropical environments. J Invertebr Pathol 2019; 168:107256. [PMID: 31614126 DOI: 10.1016/j.jip.2019.107256] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 10/25/2022]
Abstract
We determined the presence of six viruses in different bee species collected in subtropical environments. Deformed wing virus (DWV) and black queen cell virus (BQCV) were detected in >90% of honey bee samples and in 50-100% of four stingless bee, two bumble bee and one solitary bee species. Additionally, minus DWV and BQCV RNA strands were detected, indicating that the viruses replicate in several hosts. This is the first report of honey bee viruses replicating in six wild bee species in the tropics. If pathogenic to them, viral infections could result in negative impacts in agricultural and unmanaged ecosystems.
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Affiliation(s)
- José M Tapia-González
- Departamento de Ciencias de la Naturaleza, Centro Universitario del Sur, Universidad de Guadalajara, Av. Enrique Arreola Silva No. 883, Cd. Guzman, Jalisco, Mexico
| | - Nuria Morfin
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - José O Macías-Macías
- Departamento de Ciencias de la Naturaleza, Centro Universitario del Sur, Universidad de Guadalajara, Av. Enrique Arreola Silva No. 883, Cd. Guzman, Jalisco, Mexico
| | - Alvaro De la Mora
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - José C Tapia-Rivera
- Departamento de Ciencias de la Naturaleza, Centro Universitario del Sur, Universidad de Guadalajara, Av. Enrique Arreola Silva No. 883, Cd. Guzman, Jalisco, Mexico
| | - Ricardo Ayala
- Instituto de Biología, Universidad Nacional Autónoma de México, A.P. 21, Sn. Patricio, Jal., Mexico
| | - Francisca Contreras-Escareño
- Departamento de Producción Agrícola, Centro Universitario de la Costa Sur, Universidad de Guadalajara, Avenida Independencia Nacional No. 161, Autlan, Jalisco, Mexico
| | - Hanan A Gashout
- School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Ernesto Guzman-Novoa
- Departamento de Ciencias de la Naturaleza, Centro Universitario del Sur, Universidad de Guadalajara, Av. Enrique Arreola Silva No. 883, Cd. Guzman, Jalisco, Mexico; School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada.
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118
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Ryabov EV, Childers AK, Lopez D, Grubbs K, Posada-Florez F, Weaver D, Girten W, vanEngelsdorp D, Chen Y, Evans JD. Dynamic evolution in the key honey bee pathogen deformed wing virus: Novel insights into virulence and competition using reverse genetics. PLoS Biol 2019; 17:e3000502. [PMID: 31600204 PMCID: PMC6805011 DOI: 10.1371/journal.pbio.3000502] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/22/2019] [Accepted: 09/20/2019] [Indexed: 12/23/2022] Open
Abstract
The impacts of invertebrate RNA virus population dynamics on virulence and infection outcomes are poorly understood. Deformed wing virus (DWV), the main viral pathogen of honey bees, negatively impacts bee health, which can lead to colony death. Despite previous reports on the reduction of DWV diversity following the arrival of the parasitic mite Varroa destructor, the key DWV vector, we found high genetic diversity of DWV in infested United States honey bee colonies. Phylogenetic analysis showed that divergent US DWV genotypes are of monophyletic origin and were likely generated as a result of diversification after a genetic bottleneck. To investigate the population dynamics of this divergent DWV, we designed a series of novel infectious cDNA clones corresponding to coexisting DWV genotypes, thereby devising a reverse-genetics system for an invertebrate RNA virus quasispecies. Equal replication rates were observed for all clone-derived DWV variants in single infections. Surprisingly, individual clones replicated to the same high levels as their mixtures and even the parental highly diverse natural DWV population, suggesting that complementation between genotypes was not required to replicate to high levels. Mixed clone–derived infections showed a lack of strong competitive exclusion, suggesting that the DWV genotypes were adapted to coexist. Mutational and recombination events were observed across clone progeny, providing new insights into the forces that drive and constrain virus diversification. Accordingly, our results suggest that Varroa influences DWV dynamics by causing an initial selective sweep, which is followed by virus diversification fueled by negative frequency-dependent selection for new genotypes. We suggest that this selection might reflect the ability of rare lineages to evade host defenses, specifically antiviral RNA interference (RNAi). In support of this hypothesis, we show that RNAi induced against one DWV strain is less effective against an alternate strain from the same population. Deformed wing virus, a key pathogen of honey bees, shows rapid diversification after genetic bottlenecks; a novel reverse-genetic system provides insights into the forces that shape virus diversity, suggesting that virus quasi-species diversification may be driven by selection of genotypes capable of evading host RNAi defences.
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Affiliation(s)
- Eugene V. Ryabov
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
- * E-mail: ,
| | - Anna K. Childers
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
| | - Dawn Lopez
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
| | - Kyle Grubbs
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
| | - Francisco Posada-Florez
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
| | - Daniel Weaver
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
- Beeweaver Apiaries, Navasota, Texas, United States of America
| | - William Girten
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
- Department of Chemistry, Fort Lewis College, Durango, Colorado, United States of America
| | - Dennis vanEngelsdorp
- Department of Entomology, University of Maryland, College Park, Maryland, United States of America
| | - Yanping Chen
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
| | - Jay D. Evans
- Bee Research Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, USDA, Beltsville, Maryland, United States of America
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119
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DWV-A Lethal to Honey Bees ( Apis mellifera): A Colony Level Survey of DWV Variants (A, B, and C) in England, Wales, and 32 States across the US. Viruses 2019; 11:v11050426. [PMID: 31075870 PMCID: PMC6563202 DOI: 10.3390/v11050426] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 12/21/2022] Open
Abstract
The strong association between Varroa destructor, deformed wing virus (DWV), and high overwintering colony losses (OCL) of honey bees is well established. Three DWV master variants (DWV-A, -B, and -C) have been described, and their role in colony mortality remains an open question. Therefore, the aim of this study is to investigate the seasonal prevalence, viral load, and changing distribution of the three DWV master variants within honey bee colonies from England, Wales, and 32 states across the United States. Here, we report that in 2016, DWV-B was prevalent (100%, n = 249) and dominant (95%) in England and Wales, compared to the US. (56%, n = 217 and 23%, respectively), where DWV-A was prevalent (83%, n = 217) and dominant (63%). DWV-C was regularly detected in low viral loads (<1 × 107 genome equivalents per bee) and at lower prevalence (58% in England and Wales, n = 203, and 14% across the United States, n = 124) compared to DWV-A and -B. DWV-B prevalence and dominance in England and Wales coincided with low OCL (6%). Meanwhile, a 60% loss was reported by participating U.S. beekeepers. In the United States, DWV-A prevalence (89%, n = 18) and viral load were significantly (p = 0.002) higher (1 × 10 8–1 × 1011) in colonies that died when compared to the surviving colonies (49% (n = 27), 1 × 106–1 × 1010). DWV-B had low prevalence (56%, n = 18) in the colonies that died with viral loads of <1 × 1010. However, DWV-B was routinely detected in high viral loads (>1 × 1010) in surviving colonies from all sample locations, providing further supporting evidence of DWV-A exhibiting increased virulence over DWV-B at the colony level.
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120
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Brettell LE, Schroeder DC, Martin SJ. RNAseq Analysis Reveals Virus Diversity within Hawaiian Apiary Insect Communities. Viruses 2019; 11:v11050397. [PMID: 31035609 PMCID: PMC6563275 DOI: 10.3390/v11050397] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/11/2019] [Accepted: 04/24/2019] [Indexed: 12/26/2022] Open
Abstract
Deformed wing virus (DWV) is the most abundant viral pathogen of honey bees and has been associated with large-scale colony losses. DWV and other bee-associated RNA viruses are generalists capable of infecting diverse hosts. Here, we used RNAseq analysis to test the hypothesis that due to the frequency of interactions, a range of apiary pest species would become infected with DWV and/or other honey bee-associated viruses. We confirmed that DWV-A was the most prevalent virus in the apiary, with genetically similar sequences circulating in the apiary pests, suggesting frequent inter-species transmission. In addition, different proportions of the three DWV master variants as indicated by BLAST analysis and genome coverage plots revealed interesting DWV-species groupings. We also observed that new genomic recombinants were formed by the DWV master variants, which are likely adapted to replicate in different host species. Species groupings also applied when considering other viruses, many of which were widespread in the apiaries. In social wasps, samples were grouped further by site, which potentially also influenced viral load. Thus, the apiary invertebrate community has the potential to act as reservoirs of honey bee-associated viruses, highlighting the importance of considering the wider community in the apiary when considering honey bee health.
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Affiliation(s)
- Laura E Brettell
- Hawkesbury Institute for the Environment, Western Sydney University; Locked bag 1797, Penrith 2751, NSW, Australia.
- School of Environment and life Sciences, University of Salford, Manchester, M5 4WT, UK.
| | - Declan C Schroeder
- School of Biological Sciences, University of Reading, Reading RG6 6LA, UK.
- Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St Paul, MN 55108, USA.
| | - Stephen J Martin
- School of Environment and life Sciences, University of Salford, Manchester, M5 4WT, UK.
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