honey bee viruses
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To date, many viruses have been discovered to infect honey bees. In this study, we used high-throughput sequencing to expand the known virome of the honey bee, Apis mellifera, by identifying several novel DNA viruses. While the majority of previously identified bee viruses are RNA, our study reveals nine new genomes from the Parvoviridae family, tentatively named Bee densoviruses 1 to 9. In addition, we characterized a large DNA virus, Apis mellifera filamentous-like virus (AmFLV), which shares limited protein identities with the known Apis mellifera filamentous virus. The complete sequence of AmFLV, obtained by a combination of laboratory techniques and bioinformatics, spans 152,678 bp. Linear dsDNA genome encodes for 112 proteins, of which 49 are annotated. Another large virus we discovered is Apis mellifera nudivirus, which belongs to a group of Alphanudivirus. The virus has a length of 129,467 bp and a circular dsDNA genome, and has 106 protein encoding genes. The virus contains most of the core genes of the family Nudiviridae. This research demonstrates the effectiveness of viral binning in identifying viruses in honey bee virology, showcasing its initial application in this field.IMPORTANCEHoney bees contribute significantly to food security by providing pollination services. Understanding the virome of honey bees is crucial for the health and conservation of bee populations and also for the stability of the ecosystems and economies for which they are indispensable. This study unveils previously unknown DNA viruses in the honey bee virome, expanding our knowledge of potential threats to bee health. The use of the viral binning approach we employed in this study offers a promising method to uncovering and understanding the vast viral diversity in these essential pollinators.
Honey bees are globally important pollinators threatened by many different pathogens, including viruses. We investigated the virome of honey bees collected at the end of the beekeeping season (August/September) in Czechia, a Central European country. Samples were examined in biological replicates to assess the homogeneity, stability, and composition of the virome inside a single hive. By choice of healthy workers from colonies, where Varroa destructor was under control, we could identify ubiquitous bee viruses. Deformed wing virus (DWV) was highly prevalent, even though the bees were healthy, without any noticeable disease signs. The overall virome composition (consisting of honey bee-, plant-, and bacterium-infecting viruses) was driven primarily by the hive and its location. However, honey bee-specific viruses showed an uneven distribution within the same hive. In addition, our results point to an unusual cooccurrence between two rhabdoviruses and reveal the presence of five distinct lineages of Lake Sinai viruses (LSVs) clustering with other LSV strains described globally. Comparison of our results with the virome of Australian honey bees, the last truly Varroa- and DWV-free population, showed a strong difference with respect to DWV and a set of diverse members of the Picornavirales, of which the latter were absent in our samples. We hypothesize that the occurrence of DWV introduced by Varroa strongly affects the virome structure despite the mite being under control. IMPORTANCE The Western honey bee, Apis mellifera, is a vital part of our ecosystem as well as cultural heritage. Annual colony losses endanger beekeeping. In this study, we examined healthy bees from the heart of Central Europe, where honey bee colonies have been commonly affected by varroosis over 5 decades. Our virome analysis showed the presence of ubiquitous viruses in colonies where the mite Varroa destructor was under control and no honey bee disease signs were observed. Compared to previous studies, an important part of our study was the analysis of multiple replicates from individual hives. Our overall results indicate that the virome structure (including bee-infecting viruses, plant-infecting viruses, and bacteriophages) is stable within hives; however, the bee-infecting viruses varied largely within interhive replicates, suggesting variation of honey bee viruses within individual bees. Of interest was the striking difference between the viromes of our 39 pools and 9 pools of honey bee viromes previously analyzed in Australia. It could be suggested that Varroa not only affects DWV spread in bee colonies but also affects diverse members of the Picornavirales, which were strongly decreased in Czech bees compared to the Varroa- and DWV-naive Australian bees.
- Klíčová slova
- Apis mellifera, Lake Sinai virus, Picornavirales, metagenomics, rhabdovirus, viruses,
- MeSH
- bakteriofágy * MeSH
- ekosystém MeSH
- RNA-viry * MeSH
- Varroidae * MeSH
- včely MeSH
- virom MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Austrálie MeSH
Viruses contribute significantly to the global decline of honey bee populations. One way to limit the impact of such viruses is the introduction of natural antiviral compounds from fungi as a component of honey bee diets. Therefore, we examined the effect of crude organic extracts from seven strains of the fungal genus Talaromyces in honey bee diets under laboratory conditions. The strains were isolated from bee bread prepared by honey bees infected with chronic bee paralysis virus (CBPV). The antiviral effect of the extracts was also quantified in vitro using mammalian cells as a model system. We found that three extracts (from strains B13, B18 and B30) mitigated CBPV infections and increased the survival rate of bees, whereas other extracts had no effect (B11 and B49) or were independently toxic (B69 and B195). Extract B18 inhibited the replication of feline calicivirus and feline coronavirus (FCoV) in mammalian cells, whereas extracts B18 and B195 reduced the infectivity of FCoV by ~90% and 99%, respectively. Our results show that nonpathogenic fungi (and their products in food stores) offer an underexplored source of compounds that promote disease resistance in honey bees.
- Klíčová slova
- Apis mellifera, CBPV, Talaromyces, antiviral activity, fungal extracts, mycotoxins,
- MeSH
- antivirové látky farmakologie MeSH
- Ascomycota * MeSH
- kočky MeSH
- koronavirus koček * MeSH
- paralýza MeSH
- RNA-viry * MeSH
- savci MeSH
- Talaromyces * MeSH
- včely MeSH
- zvířata MeSH
- Check Tag
- kočky MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- antivirové látky MeSH
The worldwide population of western honey bees (Apis mellifera) is under pressure from habitat loss, environmental stress, and pathogens, particularly viruses that cause lethal epidemics. Deformed wing virus (DWV) from the family Iflaviridae, together with its vector, the mite Varroa destructor, is likely the major threat to the world's honey bees. However, lack of knowledge of the atomic structures of iflaviruses has hindered the development of effective treatments against them. Here, we present the virion structures of DWV determined to a resolution of 3.1 Å using cryo-electron microscopy and 3.8 Å by X-ray crystallography. The C-terminal extension of capsid protein VP3 folds into a globular protruding (P) domain, exposed on the virion surface. The P domain contains an Asp-His-Ser catalytic triad that is, together with five residues that are spatially close, conserved among iflaviruses. These residues may participate in receptor binding or provide the protease, lipase, or esterase activity required for entry of the virus into a host cell. Furthermore, nucleotides of the DWV RNA genome interact with VP3 subunits. The capsid protein residues involved in the RNA binding are conserved among honey bee iflaviruses, suggesting a putative role of the genome in stabilizing the virion or facilitating capsid assembly. Identifying the RNA-binding and putative catalytic sites within the DWV virion structure enables future analyses of how DWV and other iflaviruses infect insect cells and also opens up possibilities for the development of antiviral treatments.
- Klíčová slova
- Apis mellifera, colony collapse disorder, honey bee, structure, virus,
- MeSH
- elektronová kryomikroskopie MeSH
- kapsida ultrastruktura MeSH
- konformace proteinů MeSH
- molekulární modely MeSH
- počítačové zpracování obrazu MeSH
- proteinové domény MeSH
- RNA-viry ultrastruktura MeSH
- sekvence aminokyselin MeSH
- včely virologie MeSH
- virion ultrastruktura MeSH
- virové plášťové proteiny chemie ultrastruktura MeSH
- viry hmyzu ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- virové plášťové proteiny MeSH
Deformed wing virus (DWV) transmitted by the parasitic mite Varroa destructor is one of the most significant factors contributing to massive losses of managed colonies of western honey bee (Apis mellifera) subspecies of European origin reported worldwide in recent decades. Despite this fact, no antiviral treatment against honey bee viruses is currently available for practical applications and the level of viral infection can only be controlled indirectly by reducing the number of Varroa mites in honey bee colonies. In this study, we investigated the antiviral potential of the gypsy mushroom (Cortinarius caperatus) to reduce DWV infection in honey bees. Our results indicate that the alcohol extract of C. caperatus prevented the development of DWV infection in cage experiments as well as after direct application to honey bee colonies in a field experiment. The applied doses did not shorten the lifespan of honey bees. The reduced levels of DWV in C. caperatus-treated honey bees in cage experiments were accompanied by significant changes in the gene expression of Tep7, Bap1, and Vago. The C. caperatus treatment was not effective against the trypanosomatid Lotmaria passim. No residues of C.caperatus were found in honey harvested in the spring from colonies supplemented with the mushroom extract for their winter feeding. These findings suggest that C. caperatus alcohol extract could be a potential natural remedy to treat DWV infection in honey bees.
- Klíčová slova
- Antiviral treatment, Apis mellifera carnica, Cortinarius caperatus, Deformed wing virus, Honey bees,
- MeSH
- Agaricales * MeSH
- Cortinarius MeSH
- lidé MeSH
- RNA-viry * genetika MeSH
- Romové * MeSH
- Varroidae * MeSH
- včely MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The extensive annual loss of honey bees (Apis mellifera L.) represents a global problem affecting agriculture and biodiversity. The parasitic mite Varroa destructor, associated with viral co-infections, plays a key role in this loss. Despite years of intensive research, the complex mechanisms of Varroa - honey bee interaction are still not fully defined. Therefore, this study employed a unique combination of transcriptomic, proteomic, metabolomic, and functional analyses to reveal new details about the effect of Varroa mites and naturally associated factors, including viruses, on honey bees. We focused on the differences between Varroa parasitised and unparasitised ten-day-old worker bees collected before overwintering from the same set of colonies reared without anti-mite treatment. Supplementary comparison to honey bees collected from colonies with standard anti-Varroa treatment can provide further insights into the effect of a pyrethroid flumethrin. Analysis of the honey bees exposed to mite parasitisation revealed alterations in the transcriptome and proteome related to immunity, oxidative stress, olfactory recognition, metabolism of sphingolipids, and RNA regulatory mechanisms. The immune response and sphingolipid metabolism were strongly activated, whereas olfactory recognition and oxidative stress pathways were inhibited in Varroa parasitised honey bees compared to unparasitised ones. Moreover, metabolomic analysis confirmed the depletion of nutrients and energy stores, resulting in a generally disrupted metabolism in the parasitised workers. The combined omics-based analysis conducted on strictly parasitised bees revealed the key molecular components and mechanisms underlying the detrimental effects of Varroa sp. and its associated pathogens. This study provides the theoretical basis and interlinked datasets for further research on honey bee response to biological threats and the development of efficient control strategies against Varroa mites.
- Klíčová slova
- Honey bee, Infestation, Metabolomic, Proteomic, Transcriptomic, Varroa destructor,
- MeSH
- čich MeSH
- proteomika MeSH
- stanovení celkové genové exprese MeSH
- transkriptom MeSH
- Varroidae * fyziologie MeSH
- včely genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
INTRODUCTION: Honey bee viruses have been shown to negatively affect the vigour and longevity of European honey bees (Apis mellifera L). In the present work, beehive materials were tested for their potential to serve as non-invasive samples for honey bee virus detection. MATERIAL AND METHODS: Honey, pollen, hive debris, hive grid smears and forager honey bees were collected from 24 hives at four locations in the Czech Republic. Deformed wing virus (DWV), acute bee paralysis virus (ABPV), sacbrood virus (SBV) and black queen cell virus (BQCV) were detected using a reverse transcription PCR (RT-PCR) and real-time quantitative RT-PCR and the results for bees and alternative materials compared. RESULTS: All forager bee samples contained DWV, BQCV and SBV and 54.2% had ABPV. When comparing beehive materials to bees, the most promising results were obtained from honey and pollen samples, with BQCV and SBV detected in all honey samples and ABPV in 12.5%. Detection of SBV was achieved in 91.6% of pollen samples, detection of BQCV in 87.5% and detection of DWW in 75%. The results for debris and smears were less consistent with the viral profile of the forager samples. CONCLUSION: The best candidate materials for honey bee virus detection in a non-invasive technique are honey and pollen.
- Klíčová slova
- acute bee paralysis virus, black queen cell virus, deformed wing virus, honey bee viruses, sacbrood virus,
- Publikační typ
- časopisecké články MeSH
The spread of the parasite Varroa destructor and associated viruses has resulted in massive honey bee colony losses with considerable economic and ecological impact. The gut microbiota has a major role in shaping honey bees tolerance and resistance to parasite infestation and viral infection, but the contribution of viruses to the assembly of the host microbiota in the context of varroa resistance and susceptibility remains unclear. Here, we used a network approach including viral and bacterial nodes to characterize the impact of five viruses, Apis Rhabdovirus-1 (ARV-1), Black Queen Cell virus (BQCV), Lake Sinai virus (LSV), Sacbrood virus (SBV) and Deformed wing virus (DWV) on the gut microbiota assembly of varroa-susceptible and Gotland varroa-surviving honey bees. We found that microbiota assembly was different in varroa-surviving and varroa-susceptible honey bees with the network of the latter having a whole module not present in the network of the former. Four viruses, ARV-1, BQCV, LSV, and SBV, were tightly associated with bacterial nodes of the core microbiota of varroa-susceptible honey bees, while only two viruses BQCV and LSV, appeared correlated with bacterial nodes in varroa-surviving honey bees. In silico removal of viral nodes caused major re-arrangement of microbial networks with changes in nodes centrality and significant reduction of the networks' robustness in varroa-susceptible, but not in varroa-surviving honey bees. Comparison of predicted functional pathways in bacterial communities using PICRUSt2 showed the superpathway for heme b biosynthesis from uroporphyrinogen-III and a pathway for arginine, proline, and ornithine interconversion as significantly increased in varroa-surviving honey bees. Notably, heme and its reduction products biliverdin and bilirubin have been reported as antiviral agents. These findings show that viral pathogens are differentially nested in the bacterial communities of varroa-surviving and varroa-susceptible honey bees. These results suggest that Gotland honey bees are associated with minimally-assembled and reduced bacterial communities that exclude viral pathogens and are resilient to viral nodes removal, which, together with the production of antiviral compounds, may explain the resiliency of Gotland honey bees to viral infections. In contrast, the intertwined virus-bacterium interactions in varroa-susceptible networks suggest that the complex assembly of microbial communities in this honey bee strain favor viral infections, which may explain viral persistence in this honey bee strain. Further understanding of protective mechanisms mediated by the microbiota could help developing novel ways to control devastating viral infections affecting honey bees worldwide.
- Klíčová slova
- Honey bees, Microbiota, Varroa, Varroa-surviving, Varroa-susceptible,
- MeSH
- Dicistroviridae MeSH
- RNA-viry * MeSH
- střevní mikroflóra * MeSH
- Varroidae * MeSH
- včely MeSH
- virové nemoci * MeSH
- viry * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Among the many diseases compromising the well-being of the honey bee (Apis mellifera) the chronic paralysis syndrome of adult honey bees is one of the best described. The causative agent, chronic bee paralysis virus (CBPV), is a positive sense, single-stranded RNA virus with a segmented genome. Segment 1 encodes three putative open reading frames (ORFs), including the RNA-dependent RNA polymerase and other non-structural protein coding regions. Segment 2 encodes four putative ORFs, which contain the genes of supposed structural proteins. In this study, we established a reverse genetic system for CBPV by molecular cloning of DNA copies of both genome segments. CBPV rescue was studied in imago and honey bee pupae infection models. Virus replication and progeny virus production was only initiated when capped RNAs of both genome segments were injected in honey bees. As injection of these clonal RNAs caused clinical symptoms similar to wild-type CBPV infection, we conclude that the novel molecular clone fulfilled Koch's postulates. Our virus clone will enable in-depth analysis of CBPV pathogenesis and help to increase knowledge about this important honey bee disease.
UNLABELLED: The western honeybee (Apis mellifera) is the most important commercial insect pollinator. However, bees are under pressure from habitat loss, environmental stress, and pathogens, including viruses that can cause lethal epidemics. Slow bee paralysis virus (SBPV) belongs to the Iflaviridae family of nonenveloped single-stranded RNA viruses. Here we present the structure of the SBPV virion determined from two crystal forms to resolutions of 3.4 Å and 2.6 Å. The overall structure of the virion resembles that of picornaviruses, with the three major capsid proteins VP1 to 3 organized into a pseudo-T3 icosahedral capsid. However, the SBPV capsid protein VP3 contains a C-terminal globular domain that has not been observed in other viruses from the order Picornavirales The protruding (P) domains form "crowns" on the virion surface around each 5-fold axis in one of the crystal forms. However, the P domains are shifted 36 Å toward the 3-fold axis in the other crystal form. Furthermore, the P domain contains the Ser-His-Asp triad within a surface patch of eight conserved residues that constitutes a putative catalytic or receptor-binding site. The movements of the domain might be required for efficient substrate cleavage or receptor binding during virus cell entry. In addition, capsid protein VP2 contains an RGD sequence that is exposed on the virion surface, indicating that integrins might be cellular receptors of SBPV. IMPORTANCE: Pollination by honeybees is needed to sustain agricultural productivity as well as the biodiversity of wild flora. However, honeybee populations in Europe and North America have been declining since the 1950s. Honeybee viruses from the Iflaviridae family are among the major causes of honeybee colony mortality. We determined the virion structure of an Iflavirus, slow bee paralysis virus (SBPV). SBPV exhibits unique structural features not observed in other picorna-like viruses. The SBPV capsid protein VP3 has a large C-terminal domain, five of which form highly prominent protruding "crowns" on the virion surface. However, the domains can change their positions depending on the conditions of the environment. The domain includes a putative catalytic or receptor binding site that might be important for SBPV cell entry.
