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Molecular Detection and Differentiation of Arthropod, Fungal, Protozoan, Bacterial and Viral Pathogens of Honeybees. Vet Sci 2022; 9:vetsci9050221. [PMID: 35622749 PMCID: PMC9145064 DOI: 10.3390/vetsci9050221] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 02/01/2023] Open
Abstract
The honeybee Apis mellifera is highly appreciated worldwide because of its products, but also as it is a pollinator of crops and wild plants. The beehive is vulnerable to infections due to arthropods, fungi, protozoa, bacteria and/or viruses that manage to by-pass the individual and social immune mechanisms of bees. Due to the close proximity of bees in the beehive and their foraging habits, infections easily spread within and between beehives. Moreover, international trade of bees has caused the global spread of infections, several of which result in significant losses for apiculture. Only in a few cases can infections be diagnosed with the naked eye, by direct observation of the pathogen in the case of some arthropods, or by pathogen-associated distinctive traits. Development of molecular methods based on the amplification and analysis of one or more genes or genomic segments has brought significant progress to the study of bee pathogens, allowing for: (i) the precise and sensitive identification of the infectious agent; (ii) the analysis of co-infections; (iii) the description of novel species; (iv) associations between geno- and pheno-types and (v) population structure studies. Sequencing of bee pathogen genomes has allowed for the identification of new molecular targets and the development of specific genotypification strategies.
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2
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Soper DM, Ekroth AKE, Martins MJF. Direct evidence for increased disease resistance in polyandrous broods exists only in eusocial Hymenoptera. BMC Ecol Evol 2021; 21:189. [PMID: 34670487 PMCID: PMC8527725 DOI: 10.1186/s12862-021-01925-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/24/2021] [Indexed: 11/25/2022] Open
Abstract
Background The ‘genetic diversity’ hypothesis posits that polyandry evolved as a mechanism to increase genetic diversity within broods. One extension of this hypothesis is the ‘genetic diversity for disease resistance’ hypothesis (GDDRH). Originally designed for eusocial Hymenoptera, GDDRH states that polyandry will evolve as an effect of lower parasite prevalence in genetically variable broods. However, this hypothesis has been broadly applied to several other taxa. It is unclear how much empirical evidence supports GDDRH specifically, especially outside eusocial Hymenoptera. Results This question was addressed by conducting a literature review and posteriorly conducting meta-analyses on the data available using Hedges’s g. The literature review found 10 direct and 32 indirect studies with both having a strong publication bias towards Hymenoptera. Two meta-analyses were conducted and both found increased polyandry (direct tests; n = 8, g = 0.2283, p = < 0.0001) and genetic diversity generated by other mechanisms (indirect tests; n = 10, g = 0.21, p = < 0.0001) reduced parasite load. A subsequent moderator analysis revealed that there were no differences among Orders, indicating there may be applicability outside of Hymenoptera. However, due to publication bias and low sample size we must exercise caution with these results. Conclusion Despite the fact that the GDDRH was developed for Hymenoptera, it is frequently applied to other taxa. This study highlights the low amount of direct evidence supporting GDDRH, particularly outside of eusocial Hymenoptera. It calls for future research to address species that have high dispersal rates and contain mixes of solitary and communal nesting. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01925-3.
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Affiliation(s)
- D M Soper
- Department of Biology, University of Dallas, 1845 E. Northgate Dr., Irving, TX, 75062, USA.
| | - A K E Ekroth
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - M J F Martins
- Interdisciplinary Center for Archaeology and Evolution of Human Behaviour (ICArEHB), Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.,Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013-7012, USA
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3
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Aguero CM, Eyer P, Martin JS, Bulmer MS, Vargo EL. Natural variation in colony inbreeding does not influence susceptibility to a fungal pathogen in a termite. Ecol Evol 2021; 11:3072-3083. [PMID: 33841768 PMCID: PMC8019025 DOI: 10.1002/ece3.7233] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 01/08/2021] [Accepted: 01/15/2021] [Indexed: 01/26/2023] Open
Abstract
Reduced genetic diversity through inbreeding can negatively affect pathogen resistance. This relationship becomes more complicated in social species, such as social insects, since the chance of disease transmission increases with the frequency of interactions among individuals. However, social insects may benefit from social immunity, whereby individual physiological defenses may be bolstered by collective-level immune responses, such as grooming or sharing of antimicrobial substance through trophallaxis. We set out to determine whether differences in genetic diversity between colonies of the subterranean termite, Reticulitermes flavipes, accounts for colony survival against pathogens. We sampled colonies throughout the United States (Texas, North Carolina, Maryland, and Massachusetts) and determined the level of inbreeding of each colony. To assess whether genetically diverse colonies were better able to survive exposure to diverse pathogens, we challenged groups of termite workers with two strains of a pathogenic fungus, one local strain present in the soil surrounding sampled colonies and another naïve strain, collected outside the range of this species. We found natural variation in the level of inbreeding between colonies, but this variation did not explain differences in susceptibility to either pathogen. Although the naïve strain was found to be more hazardous than the local strain, colony resistance was correlated between two strains, meaning that colonies had either relatively high or low susceptibility to both strains regardless of their inbreeding coefficient. Overall, our findings may reflect differential virulence between the strains, immune priming of the colonies via prior exposure to the local strain, or a coevolved resistance toward this strain. They also suggest that colony survival may rely more upon additional factors, such as different behavioral response thresholds or the influence of a specific genetic background, rather than the overall genetic diversity of the colony.
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Affiliation(s)
- Carlos M. Aguero
- Department of EntomologyTexas A&M UniversityCollege StationTXUSA
| | | | - Jason S. Martin
- Department of Biological SciencesTowson UniversityTowsonMDUSA
| | - Mark S. Bulmer
- Department of Biological SciencesTowson UniversityTowsonMDUSA
| | - Edward L. Vargo
- Department of EntomologyTexas A&M UniversityCollege StationTXUSA
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Gerdts JR, Roberts JMK, Simone-Finstrom M, Ogbourne SM, Tucci J. Genetic variation of Ascosphaera apis and colony attributes do not explain chalkbrood disease outbreaks in Australian honey bees. J Invertebr Pathol 2021; 180:107540. [PMID: 33516722 DOI: 10.1016/j.jip.2021.107540] [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: 07/16/2020] [Revised: 01/06/2021] [Accepted: 01/22/2021] [Indexed: 11/30/2022]
Abstract
Chalkbrood infection caused by the fungus Ascosphaera apis currently has a significant impact on Australia's apicultural industry. We investigated the genetic variation of A. apis and colony and apiary level conditions to determine if an emerging, more virulent strain or specific conditions were responsible for the prevalence of the disease. We identified six genetically distinct strains of A. apis, four have been reported elsewhere and two are unique to Australia. Colonies and individual larvae were found to be infected with multiple strains of A. apis, neither individual strains, combinations of strains, or obvious colony or apiary characteristics were found to be predictive of hive infection levels. These results suggest that host genotype plays an important role in colony level resistance to chalkbrood infection in Australia.
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Affiliation(s)
- Jody R Gerdts
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute of Molecular Science, La Trobe University, PO Box 199, Bendigo, Victoria 3552, Australia.
| | - John M K Roberts
- Commonwealth Scientific and Industrial Research Organisation, Clunes Ross Street, Canberra, Australian Capital Territory 2601, Australia.
| | - Michael Simone-Finstrom
- Honey Bee Breeding, Genetics, and Physiology Laboratory, 1157 Ben Hur Road, Baton Rouge, LA 70820, United States.
| | - Steven M Ogbourne
- GeneCology Research Centre, University of the Sunshine Coast, 90 Sippy Downs Drive, Maroochydore 4556, Queensland, Australia; School of Science Engineering & Technology, University of the Sunshine Coast, 90 Sippy Downs Drive, Maroochydore 4556, Queensland, Australia.
| | - Joseph Tucci
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute of Molecular Science, La Trobe University, PO Box 199, Bendigo, Victoria 3552, Australia.
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Getachew A, Abejew TA, Wu J, Xu J, Yu H, Tan J, Wu P, Tu Y, Kang W, Wang Z, Xu S. Transcriptome profiling reveals insertional mutagenesis suppressed the expression of candidate pathogenicity genes in honeybee fungal pathogen, Ascosphaera apis. Sci Rep 2020; 10:7532. [PMID: 32372055 PMCID: PMC7200787 DOI: 10.1038/s41598-020-64022-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 04/03/2020] [Indexed: 11/30/2022] Open
Abstract
Chalkbrood disease is caused by Ascosphaera apis which severely affects honeybee brood. Spore inoculation experiments shown pathogenicity varies among different strains and mutants, however, the molecular mechanism of pathogenicity is unclear. We sequenced, assembled and annotated the transcriptomes of wild type (SPE1) and three mutants (SPE2, SPE3 and SPE4) with reduced pathogenicity that were constructed in our previous study. Illumina sequencing generated a total of 394,910,604 clean reads and de novo Trinity-based assembled into 12,989 unigenes, among these, 9,598 genes were successfully annotated to known proteins in UniProt database. A total of 172, 3,996, and 650 genes were up-regulated and 4,403, 2,845, and 3,016 genes were down-regulated between SPE2-SPE1, SPE3-SPE1, and SPE4-SPE1, respectively. Overall, several genes with a potential role in fungal pathogenicity were detected down-regulated in mutants including 100 hydrolytic enzymes, 117 transcriptional factors, and 47 cell wall related genes. KEGG pathway enrichment analysis reveals 216 genes involved in nine pathways were down-regulated in mutants compared to wild type. The down-regulation of more pathways involved in pathogenicity in SPE2 and SPE4 than SPE3 supports their lower pathogenicity during in-vitro bioassay experiment. Expression of 12 down-regulated genes in mutants was validated by quantitative real time PCR. This study provides valuable information on transcriptome variation caused by mutation for further functional validation of candidate pathogenicity genes in A. apis.
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Affiliation(s)
- Awraris Getachew
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
- College of Agriculture and Environmental Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Tessema Aynalem Abejew
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
- College of Agriculture and Environmental Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Jiangli Wu
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
| | - Jin Xu
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
| | - Huimin Yu
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
| | - Jing Tan
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
| | - Pengjie Wu
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
| | - Yangyang Tu
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
| | - Weipeng Kang
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
| | - Zheng Wang
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China
| | - Shufa Xu
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture; Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, 100093, Beijing, China.
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Aguero CM, Eyer PA, Vargo EL. Increased genetic diversity from colony merging in termites does not improve survival against a fungal pathogen. Sci Rep 2020; 10:4212. [PMID: 32144325 PMCID: PMC7060273 DOI: 10.1038/s41598-020-61278-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/24/2020] [Indexed: 12/26/2022] Open
Abstract
In some species of social insects the increased genetic diversity from having multiple breeders in a colony has been shown to improve pathogen resistance. Termite species typically found colonies from single mated pairs and therefore may lack the flexibility to buffer pathogen pressure with increased genetic diversity by varying the initial number of reproductives. However, they can later increase group diversity through colony merging, resulting in a genetically diverse, yet cohesive, workforce. In this study, we investigate whether the increased group diversity from colony fusion benefits social immunity in the subterranean termite Reticulitermes flavipes. We confirm previous findings that colonies of R. flavipes will readily merge and we show that workers will equally groom nestmates and non-nestmates after merging. Despite this, the survival of these merged colonies was not improved after exposure to a fungal pathogen, but instead leveled to that of the more susceptible or the more resistant colony. Our study brings little support to the hypothesis that colony fusion may improve immunity through an increase of genetic diversity in R. flavipes. Instead, we find that following exposure to a lethal pathogen, one colony is heavily influential to the entire group's survival after merging.
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Affiliation(s)
- Carlos M Aguero
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, Texas, 77843-2143, USA.
| | - Pierre-André Eyer
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, Texas, 77843-2143, USA
| | - Edward L Vargo
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, Texas, 77843-2143, USA
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CASTAGNINO GLB, MATEOS A, MEANA A, MONTEJO L, ZAMORANO ITURRALDE LV, CUTULI DE SIMÓN MT. Etiology, symptoms and prevention of chalkbrood disease: a literature review. REVISTA BRASILEIRA DE SAÚDE E PRODUÇÃO ANIMAL 2020. [DOI: 10.1590/s1519-9940210332020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
ABSTRACT The fungus Ascosphaera apis, responsible for causing the chalkbrood disease of honey bees, is widely present in temperate regions of the northern hemisphere, but has also spread to other regions of the world such as Brazil. Although it is not usually lethal for the colony, it can reduce its population, hampering its development. This study is a review on the disease that presents a broad overview of its development, identification methods as well as ways to control it. Research shows that chalkbrood is associated with several factors and is most frequently found in colonies of Apis bees during the spring, when there is excess humidity and sudden temperature changes in the hive. Other factors such as viral or bacterial infection, the presence of the ectoparasite Varroa destructor, pesticide poisoning and poor nutrition of nurse bees can also affect its incidence and severity. Field diagnosis is made based on the presence of hardened mummified brood in the pupal stage, of white or black color, in the cells and entrance. Affected cells show dead pupae covered with white mycelia, resembling cotton, or hardened, dry and brittle, resembling chalk pieces, which originated the name. To date, there are no efficient methods to reduce the damage caused by chalkbrood. Genetic selection of bees with higher hygienic behavior and disease resistance is recommended.
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8
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Gerdts J, Dewar RL, Simone Finstrom M, Edwards T, Angove M. Hygienic behaviour selection via freeze-killed honey bee brood not associated with chalkbrood resistance in eastern Australia. PLoS One 2018; 13:e0203969. [PMID: 30427850 PMCID: PMC6235251 DOI: 10.1371/journal.pone.0203969] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 10/19/2018] [Indexed: 11/18/2022] Open
Abstract
Hygienic behaviour is a social immune response in honey bees shown to help provide resistance to honey bee pests and diseases. A survey of hygienic behaviour and brood diseases was conducted on 649 colonies in eastern Australia to initiate a selective breeding program targeting disease resistance and provide a level of resistance to Varroa (Varroa destructor Anderson and Trueman and V. jacobsoni Oudemans) mites should they become established in Australia. The test population showed a remarkably high baseline level of hygienic behaviour with 17% of colonies meeting or exceeding breeding selection thresholds. Colonies belonging to a breeding program were 5.8 times more likely to be highly hygienic and colonies headed by queens raised from hygienic queen mothers were 2.2 times more likely. Nectar availability (nectar yielding flowering plants within honey bee forage range) influenced hygienic behaviour expression but was not a significant predictor of level of hygienic behaviour. Surprisingly, hygienic behaviour was not a significant predictor of the presence of infection of the honey bee brood disease chalkbrood (Ascosphaera apis) and was not influential in predicting severity of chalkbrood infection in surveyed honey bee colonies. This study, along with reports from commercial beekeepers that chalkbrood infection is on the rise, warrants a deeper exploration of the host-pathogen relationship between Apis mellifera and Ascosphaera apis in Australia.
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Affiliation(s)
- Jody Gerdts
- Department of Pharmacy and Applied Science, La Trobe University, Bendigo, Victoria, Australia
| | - R. Laurie Dewar
- Honey Bee Breeding Program, Dewar Apiaries, Kalbar, Queensland, Australia
| | - Michael Simone Finstrom
- Honey Bee Breeding, Genetics, and Physiology Laboratory, USDA-ARS, Baton Rouge, Louisiana, United States of America
| | - Trevor Edwards
- Department of Agriculture and Water Resources, Tullamarine Vic, Australia
| | - Michael Angove
- Department of Pharmacy and Applied Science, La Trobe University, Bendigo, Victoria, Australia
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9
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Affiliation(s)
- Qingyun Diao
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, P. R. China
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture, Haidian District, Beijing, P. R. China
| | - Chunsheng Hou
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, P. R. China
- Key Laboratory of Pollinating Insect Biology, Ministry of Agriculture, Haidian District, Beijing, P. R. China
- * E-mail:
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Chen D, Guo R, Xu X, Xiong C, Liang Q, Zheng Y, Luo Q, Zhang Z, Huang Z, Kumar D, Xi W, Zou X, Liu M. Uncovering the immune responses of Apis mellifera ligustica larval gut to Ascosphaera apis infection utilizing transcriptome sequencing. Gene 2017; 621:40-50. [DOI: 10.1016/j.gene.2017.04.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 03/30/2017] [Accepted: 04/14/2017] [Indexed: 01/11/2023]
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11
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Simone-Finstrom M. Social Immunity and the Superorganism: Behavioral Defenses Protecting Honey Bee Colonies from Pathogens and Parasites. ACTA ACUST UNITED AC 2017. [DOI: 10.1080/0005772x.2017.1307800] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Liu Y, Yan L, Li Z, Huang WF, Pokhrel S, Liu X, Su S. Larva-mediated chalkbrood resistance-associated single nucleotide polymorphism markers in the honey bee Apis mellifera. INSECT MOLECULAR BIOLOGY 2016; 25:239-250. [PMID: 26991518 DOI: 10.1111/imb.12216] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Chalkbrood is a disease affecting honey bees that seriously impairs brood growth and productivity of diseased colonies. Although honey bees can develop chalkbrood resistance naturally, the details underlying the mechanisms of resistance are not fully understood, and no easy method is currently available for selecting and breeding resistant bees. Finding the genes involved in the development of resistance and identifying single nucleotide polymorphisms (SNPs) that can be used as molecular markers of resistance is therefore a high priority. We conducted genome resequencing to compare resistant (Res) and susceptible (Sus) larvae that were selected following in vitro chalkbrood inoculation. Twelve genomic libraries, including 14.4 Gb of sequence data, were analysed using SNP-finding algorithms. Unique SNPs derived from chromosomes 2 and 11 were analysed in this study. SNPs from resistant individuals were confirmed by PCR and Sanger sequencing using in vitro reared larvae and resistant colonies. We found strong support for an association between the C allele at SNP C2587245T and chalkbrood resistance. SNP C2587245T may be useful as a genetic marker for the selection of chalkbrood resistance and high royal jelly production honey bee lines, thereby helping to minimize the negative effects of chalkbrood on managed honey bees.
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Affiliation(s)
- Y Liu
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - L Yan
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Z Li
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - W-F Huang
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Illinois, USA
| | - S Pokhrel
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - X Liu
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - S Su
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Animal Sciences, Zhejiang University, Hangzhou, China
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Klinger EG, Vojvodic S, DeGrandi-Hoffman G, Welker DL, James RR. Mixed infections reveal virulence differences between host-specific bee pathogens. J Invertebr Pathol 2015; 129:28-35. [PMID: 25982695 DOI: 10.1016/j.jip.2015.05.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 04/27/2015] [Accepted: 05/05/2015] [Indexed: 02/04/2023]
Abstract
Dynamics of host-pathogen interactions are complex, often influencing the ecology, evolution and behavior of both the host and pathogen. In the natural world, infections with multiple pathogens are common, yet due to their complexity, interactions can be difficult to predict and study. Mathematical models help facilitate our understanding of these evolutionary processes, but empirical data are needed to test model assumptions and predictions. We used two common theoretical models regarding mixed infections (superinfection and co-infection) to determine which model assumptions best described a group of fungal pathogens closely associated with bees. We tested three fungal species, Ascosphaera apis, Ascosphaera aggregata and Ascosphaera larvis, in two bee hosts (Apis mellifera and Megachile rotundata). Bee survival was not significantly different in mixed infections vs. solo infections with the most virulent pathogen for either host, but fungal growth within the host was significantly altered by mixed infections. In the host A. mellifera, only the most virulent pathogen was present in the host post-infection (indicating superinfective properties). In M. rotundata, the most virulent pathogen co-existed with the lesser-virulent one (indicating co-infective properties). We demonstrated that the competitive outcomes of mixed infections were host-specific, indicating strong host specificity among these fungal bee pathogens.
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Affiliation(s)
- Ellen G Klinger
- USDA-ARS Pollinating Insect Research Unit, 1410 North 800 East, Logan, UT 84341, United States; Utah State University, 5305 Old Main Hill, Logan, UT 84322, United States.
| | - Svjetlana Vojvodic
- University of Arizona, Center for Insect Science, 1041 E. Lowell St., Tucson, AZ 85721, United States
| | - Gloria DeGrandi-Hoffman
- USDA-ARS Carl Hayden Bee Research Center, 2000 East Allen Road, Tucson, AZ 85721, United States
| | - Dennis L Welker
- Utah State University, 5305 Old Main Hill, Logan, UT 84322, United States
| | - Rosalind R James
- USDA-ARS Pollinating Insect Research Unit, 1410 North 800 East, Logan, UT 84341, United States
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