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Blot N, Clémencet J, Jourda C, Lefeuvre P, Warrit N, Esnault O, Delatte H. Geographic population structure of the honeybee microsporidian parasite Vairimorpha (Nosema) ceranae in the South West Indian Ocean. Sci Rep 2023; 13:12122. [PMID: 37495608 PMCID: PMC10372035 DOI: 10.1038/s41598-023-38905-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023] Open
Abstract
The microsporidian Vairimorpha (Nosema) ceranae is one of the most common parasites of the honeybee. A single honeybee carries many parasites and therefore multiple alleles of V. ceranae genes that seem to be ubiquitous. As a consequence, nucleotide diversity analyses have not allowed discriminating genetic structure of parasite populations. We performed deep loci-targeted sequencing to monitor the haplotype frequencies of genome markers in isolates from discontinuous territories, namely the tropical islands of the South West Indian Ocean. The haplotype frequency distribution corroborated the suspected tetraploidy of the parasite. Most major haplotypes were ubiquitous in the area but with variable frequency. While oceanic isolates differed from European and Asian outgroups, parasite populations from distinct archipelagoes also differed in their haplotype distribution. Interestingly an original and very divergent Malagasy isolate was detected. The observed population structure allowed formulating hypotheses upon the natural history of V. ceranae in this oceanic area. We also discussed the usefulness of allelic distribution assessment, using multiple informative loci or genome-wide analyses, when parasite population is not clonal within a single host.
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Affiliation(s)
- Nicolas Blot
- Université Clermont Auvergne, CNRS, "Laboratoire Microorganismes: Génome et Environnement", Clermont-Ferrand, France.
| | - Johanna Clémencet
- Université de la Réunion, UMR Peuplements Végétaux et Bio-agresseurs en Milieu Tropical, 97410, Saint-Pierre, La Réunion, France
| | - Cyril Jourda
- CIRAD, UMR Peuplements Végétaux et Bio-agresseurs en Milieu Tropical, 97410, Saint-Pierre, La Réunion, France
| | - Pierre Lefeuvre
- CIRAD, UMR Peuplements Végétaux et Bio-agresseurs en Milieu Tropical, 97410, Saint-Pierre, La Réunion, France
| | - Natapot Warrit
- Center of Excellence in Entomology, Department of Biology, Faculty of Sciences, Chulalongkorn University, Bangkok, Thailand
| | - Olivier Esnault
- Groupement de Défense Sanitaire de la Réunion, La Plaine des Cafres, France
| | - Hélène Delatte
- CIRAD, UMR Peuplements Végétaux et Bio-agresseurs en Milieu Tropical, 101, Antananarivo, Madagascar
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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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Polymorphism of 16s rRNA Gene: Any Effect on the Biomolecular Quantitation of the Honey Bee (Apis mellifera L., 1758) Pathogen Nosema ceranae? APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12010422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The microsporidian Nosema ceranae is a severe threat to the western honey bee Apis mellifera, as it is responsible for nosemosis type C, which leads the colonies to dwindle and collapse. Infection quantification is essential to clinical and research aims. Assessment is made often with molecular assays based on rRNA genes, which are present in the N. ceranae genome as multiple and polymorphic copies. This study aims to compare two different methods of Real-Time PCR (qPCR), respectively relying on the 16S rRNA and Hsp70 genes, the first of which is described as a multiple and polymorphic gene. Young worker bees, hatched in the laboratory and artificially inoculated with N. ceranae spores, were incubated at 33 °C and subject to different treatment regimens. Samples were taken post-infection and analyzed with both qPCR methods. Compared to Hsp70, the 16S rRNA method systematically detected higher abundance. Straightforward conversion between the two methods is made impossible by erratic 16s rRNA/Hsp70 ratios. The 16s rRNA polymorphism showed an increase around the inoculated dose, where a higher prevalence of ungerminated spores was expected due to the treatment effects. The possible genetic background of that irregular distribution is discussed in detail. The polymorphic nature of 16S rRNA showed to be a limit in the infection quantification. More reliably, the N. ceranae abundance can be assessed in honey bee samples with methods based on the single-copy gene Hsp70.
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Cameron TC, Wiles D, Beddoe T. Current Status of Loop-Mediated Isothermal Amplification Technologies for the Detection of Honey Bee Pathogens. Front Vet Sci 2021; 8:659683. [PMID: 33912610 PMCID: PMC8071855 DOI: 10.3389/fvets.2021.659683] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/18/2021] [Indexed: 11/25/2022] Open
Abstract
Approximately one-third of the typical human Western diet depends upon pollination for production, and honey bees (Apis mellifera) are the primary pollinators of numerous food crops, including fruits, nuts, vegetables, and oilseeds. Regional large scale losses of managed honey bee populations have increased significantly during the last decade. In particular, asymptomatic infection of honey bees with viruses and bacterial pathogens are quite common, and co-pathogenic interaction with other pathogens have led to more severe and frequent colony losses. Other multiple environmental stress factors, including agrochemical exposure, lack of quality forage, and reduced habitat, have all contributed to the considerable negative impact upon bee health. The ability to accurately diagnose diseases early could likely lead to better management and treatment strategies. While many molecular diagnostic tests such as real-time PCR and MALDI-TOF mass spectrometry have been developed to detect honey bee pathogens, they are not field-deployable and thus cannot support local apiary husbandry decision-making for disease control. Here we review the field-deployable technology termed loop-mediated isothermal amplification (LAMP) and its application to diagnose honey bee infections.
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Affiliation(s)
- Timothy C Cameron
- Department of Animal, Plant and Soil Science, Centre for AgriBioscience, La Trobe University, Melbourne, VIC, Australia.,Centre for Livestock Interactions With Pathogens, La Trobe University, Melbourne, VIC, Australia
| | - Danielle Wiles
- Department of Animal, Plant and Soil Science, Centre for AgriBioscience, La Trobe University, Melbourne, VIC, Australia.,Centre for Livestock Interactions With Pathogens, La Trobe University, Melbourne, VIC, Australia
| | - Travis Beddoe
- Department of Animal, Plant and Soil Science, Centre for AgriBioscience, La Trobe University, Melbourne, VIC, Australia.,Centre for Livestock Interactions With Pathogens, La Trobe University, Melbourne, VIC, Australia
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Lannutti L, Mira A, Basualdo M, Rodriguez G, Erler S, Silva V, Gisder S, Genersch E, Florin-Christensen M, Schnittger L. Development of a loop-mediated isothermal amplification (LAMP) and a direct LAMP for the specific detection of Nosema ceranae, a parasite of honey bees. Parasitol Res 2020; 119:3947-3956. [DOI: 10.1007/s00436-020-06915-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 09/29/2020] [Indexed: 02/08/2023]
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Peters MJ, Suwannapong G, Pelin A, Corradi N. Genetic and Genome Analyses Reveal Genetically Distinct Populations of the Bee Pathogen Nosema ceranae from Thailand. MICROBIAL ECOLOGY 2019; 77:877-889. [PMID: 30288544 DOI: 10.1007/s00248-018-1268-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/25/2018] [Indexed: 06/08/2023]
Abstract
The recent global decline in Western honeybee (Apis mellifera) populations is of great concern for pollination and honey production worldwide. Declining honeybee populations are frequently infected by the microsporidian pathogen Nosema ceranae. This species was originally described in the Asiatic honeybee (Apis cerana), and its identification in global A. mellifera hives could result from a recent host transfer. Recent genome studies have found that global populations of this parasite are polyploid and that humans may have fueled their global expansion. To better understand N. ceranae biology, we investigated its genetic diversity within part of their native range (Thailand) and among different hosts (A. mellifera, A. cerana) using both PCR and genome-based methods. We find that Thai N. ceranae populations share many SNPs with other global populations and appear to be clonal. However, in stark contrast with previous studies, we found that these populations also carry many SNPs not found elsewhere, indicating that these populations have evolved in their current geographic location for some time. Our genome analyses also indicate the potential presence of diploidy within Thai populations of N. ceranae.
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Affiliation(s)
- Melissa J Peters
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Adrian Pelin
- Department of Biochemistry, University of Ottawa, Ottawa, Ontario, Canada
- Center for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Nicolas Corradi
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
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Martín-Hernández R, Bartolomé C, Chejanovsky N, Le Conte Y, Dalmon A, Dussaubat C, García-Palencia P, Meana A, Pinto MA, Soroker V, Higes M. Nosema ceranaeinApis mellifera: a 12 years postdetectionperspective. Environ Microbiol 2018; 20:1302-1329. [DOI: 10.1111/1462-2920.14103] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/07/2018] [Accepted: 03/11/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Raquel Martín-Hernández
- Laboratorio de Patología Apícola. Centro de Investigación Apícola y Agroambiental de Marchamalo, (CIAPA-IRIAF), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha; Marchamalo Spain
- Instituto de Recursos Humanos para la Ciencia y la Tecnología (INCRECYT-FEDER), Fundación Parque Científico y Tecnológico de Castilla - La Mancha; Spain
| | - Carolina Bartolomé
- Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela. Xenómica Comparada de Parásitos Humanos, IDIS, 15782 Santiago de Compostela; Galicia Spain
| | - Nor Chejanovsky
- Agricultural Research Organization, The Volcani Center; Rishon LeZion Israel
| | - Yves Le Conte
- INRA, UR 406 Abeilles et Environnement; F-84000 Avignon France
| | - Anne Dalmon
- INRA, UR 406 Abeilles et Environnement; F-84000 Avignon France
| | | | | | - Aranzazu Meana
- Facultad de Veterinaria, Universidad Complutense de Madrid; Spain
| | - M. Alice Pinto
- Mountain Research Centre (CIMO), Polytechnic Institute of Bragança; 5300-253 Bragança Portugal
| | - Victoria Soroker
- Agricultural Research Organization, The Volcani Center; Rishon LeZion Israel
| | - Mariano Higes
- Laboratorio de Patología Apícola. Centro de Investigación Apícola y Agroambiental de Marchamalo, (CIAPA-IRIAF), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha; Marchamalo Spain
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Sagastume S, Martín-Hernández R, Higes M, Henriques-Gil N. Genotype diversity in the honey bee parasite Nosema ceranae: multi-strain isolates, cryptic sex or both? BMC Evol Biol 2016; 16:216. [PMID: 27756211 PMCID: PMC5069816 DOI: 10.1186/s12862-016-0797-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 10/11/2016] [Indexed: 11/10/2022] Open
Abstract
Background There is great controversy as to whether Microsporidia undergo a sexual cycle. In the paradigmatic case of Nosema ceranae, although there is no morphological evidence of sex, some meiosis-specific genes are present in its reduced genome and there is also high intraspecific variability, with incongruent phylogenies having been systematically obtained. The possibility of sexual recombination is important from an epidemiological standpoint, particularly as N. ceranae is considered to be a major factor in the current disquieting epidemic of widespread bee colony losses. This parasite apparently originated in oriental honey bees, spreading out of Asia and Australia to infect honey bees worldwide. This study had three main objectives: i) to obtain genetic markers that are not part of known multi-copy arrays for strain determination; ii) to shed light on the intraspecific variability and recombination of N. ceranae; and iii) to assess the variability in N. ceranae populations. The answers to these questions are critical to understand the capacity of adaptation of microsporidia. Results Biallelic polymorphisms were detected at a number of specific points in the five coding loci analyzed from European and Australian isolates of N. ceranae. Heterozygous genotypes were abundant and cloning experiments demonstrate that they reflect the existence of multiple alternative sequences in each isolate. The comparisons of different clones and genotypes clearly indicate that new haplotypes are generated by homologous recombination. Conclusions The N. ceranae isolates from honey bees correspond to genotypically distinct populations, revealing that individual honey bees may not be infected by a particular clone but rather, a pool of different strains. Homologous recombination implies the existence of a cryptic sex cycle yet to be described in N. ceranae. There are no diagnostic alleles associated with Australian or European origins, nor are there differences between the two hosts, A. cerana and A. mellifera, supporting the absence of biological barriers for N. ceranae transmission. Diversity is high among microsporidia of both these origins, and the maintenance of a high heterozygosis in the recently invaded European populations, could hypothetically underlie the stronger virulence of N. ceranae observed in A. mellifera.
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Affiliation(s)
- Soledad Sagastume
- Centro Apícola Regional, Bee Pathology Laboratory, 19180, Marchamalo, Guadalajara, Spain.
| | - Raquel Martín-Hernández
- Centro Apícola Regional, Bee Pathology Laboratory, 19180, Marchamalo, Guadalajara, Spain.,Instituto de Recursos Humanos para la Ciencia y la Tecnología (INCRECYT), Parque Científico de Albacete, Spain
| | - Mariano Higes
- Centro Apícola Regional, Bee Pathology Laboratory, 19180, Marchamalo, Guadalajara, Spain
| | - Nuno Henriques-Gil
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina, Universidad CEU San Pablo, Campus de Montepríncipe, 28668, Madrid, Spain
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Maside X, Gómez-Moracho T, Jara L, Martín-Hernández R, De la Rúa P, Higes M, Bartolomé C. Population Genetics of Nosema apis and Nosema ceranae: One Host (Apis mellifera) and Two Different Histories. PLoS One 2015; 10:e0145609. [PMID: 26720131 PMCID: PMC4699903 DOI: 10.1371/journal.pone.0145609] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 12/07/2015] [Indexed: 12/26/2022] Open
Abstract
Two microsporidians are known to infect honey bees: Nosema apis and Nosema ceranae. Whereas population genetics data for the latter have been released in the last few years, such information is still missing for N. apis. Here we analyze the patterns of nucleotide polymorphism at three single-copy loci (PTP2, PTP3 and RPB1) in a collection of Apis mellifera isolates from all over the world, naturally infected either with N. apis (N = 22) or N. ceranae (N = 23), to provide new insights into the genetic diversity, demography and evolution of N. apis, as well as to compare them with evidence from N. ceranae. Neutral variation in N. apis and N. ceranae is of the order of 1%. This amount of diversity suggests that there is no substantial differentiation between the genetic content of the two nuclei present in these parasites, and evidence for genetic recombination provides a putative mechanism for the flow of genetic information between chromosomes. The analysis of the frequency spectrum of neutral variants reveals a significant surplus of low frequency variants, particularly in N. ceranae, and suggests that the populations of the two pathogens are not in mutation-drift equilibrium and that they have experienced a population expansion. Most of the variation in both species occurs within honey bee colonies (between 62%-90% of the total genetic variance), although in N. apis there is evidence for differentiation between parasites isolated from distinct A. mellifera lineages (20%-34% of the total variance), specifically between those collected from lineages A and C (or M). This scenario is consistent with a long-term host-parasite relationship and contrasts with the lack of differentiation observed among host-lineages in N. ceranae (< 4% of the variance), which suggests that the spread of this emergent pathogen throughout the A. mellifera worldwide population is a recent event.
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Affiliation(s)
- Xulio Maside
- Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
- Xenómica Comparada de Parásitos Humanos, IDIS, Santiago de Compostela, Galicia, Spain
- Departamento de Anatomía Patolóxica e Ciencias Forenses, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
| | - Tamara Gómez-Moracho
- Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
- Xenómica Comparada de Parásitos Humanos, IDIS, Santiago de Compostela, Galicia, Spain
- Laboratorio de Patología Apícola. Centro de Investigación Apícola y Agroambiental (CIAPA), Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Marchamalo, Guadalajara, Spain
| | - Laura Jara
- Departamento de Zoología y Antropología Física, Facultad de Veterinaria, Universidad de Murcia, Murcia, Spain
| | - Raquel Martín-Hernández
- Laboratorio de Patología Apícola. Centro de Investigación Apícola y Agroambiental (CIAPA), Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Marchamalo, Guadalajara, Spain
- Instituto de Recursos Humanos para la Ciencia y la Tecnología (INCRECYT-FEDER), Fundación Parque Científico y Tecnológico de Albacete, Albacete, Spain
| | - Pilar De la Rúa
- Departamento de Zoología y Antropología Física, Facultad de Veterinaria, Universidad de Murcia, Murcia, Spain
| | - Mariano Higes
- Laboratorio de Patología Apícola. Centro de Investigación Apícola y Agroambiental (CIAPA), Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, Marchamalo, Guadalajara, Spain
| | - Carolina Bartolomé
- Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain
- Xenómica Comparada de Parásitos Humanos, IDIS, Santiago de Compostela, Galicia, Spain
- * E-mail:
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Pelin A, Selman M, Aris-Brosou S, Farinelli L, Corradi N. Genome analyses suggest the presence of polyploidy and recent human-driven expansions in eight global populations of the honeybee pathogen Nosema ceranae. Environ Microbiol 2015; 17:4443-58. [PMID: 25914091 DOI: 10.1111/1462-2920.12883] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 04/13/2015] [Accepted: 04/15/2015] [Indexed: 12/23/2022]
Abstract
Nosema ceranae is a microsporidian pathogen whose infections have been associated with recent global declines in the populations of western honeybees (Apis mellifera). Despite the outstanding economic and ecological threat that N. ceranae may represent for honeybees worldwide, many aspects of its biology, including its mode of reproduction, propagation and ploidy, are either very unclear or unknown. In the present study, we set to gain knowledge in these biological aspects by re-sequencing the genome of eight isolates (i.e. a population of spores isolated from one single beehive) of this species harvested from eight geographically distant beehives, and by investigating their level of polymorphism. Consistent with previous analyses performed using single gene sequences, our analyses uncovered the presence of very high genetic diversity within each isolate, but also very little hive-specific polymorphism. Surprisingly, the nature, location and distribution of this genetic variation suggest that beehives around the globe are infected by a population of N. ceranae cells that may be polyploid (4n or more), and possibly clonal. Lastly, phylogenetic analyses based on genome-wide single-nucleotide polymorphism data extracted from these parasites and mitochondrial sequences from their hosts all failed to support the current geographical structure of our isolates.
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Affiliation(s)
- Adrian Pelin
- Canadian Institute for Advanced Research, Department of Biology; University of Ottawa, Ottawa, ON, Canada
| | - Mohammed Selman
- Canadian Institute for Advanced Research, Department of Biology; University of Ottawa, Ottawa, ON, Canada
| | - Stéphane Aris-Brosou
- Departments of Biology and of Mathematics & Statistics, University of Ottawa, Ottawa, ON, Canada
| | - Laurent Farinelli
- FASTERIS S.A., Ch. du Pont-du-Centenaire 109, P.O. Box 28, Plan-les-Ouates, CH-1228, Geneva, Switzerland
| | - Nicolas Corradi
- Canadian Institute for Advanced Research, Department of Biology; University of Ottawa, Ottawa, ON, Canada
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Gómez-Moracho T, Bartolomé C, Martín-Hernández R, Higes M, Maside X. Evidence for weak genetic recombination at the PTP2 locus of Nosema ceranae. Environ Microbiol 2014; 17:1300-9. [PMID: 25052231 DOI: 10.1111/1462-2920.12574] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 07/17/2014] [Indexed: 11/29/2022]
Abstract
The microsporidian Nosema ceranae is an emergent pathogen that threatens the health of honeybees and other pollinators all over the world. Its recent rapid spread across a wide variety of host species and environments demonstrated an enhanced ability of adaptation, which seems to contradict the lack of evidence for genetic recombination and the absence of a sexual stage in its life cycle. Here we retrieved fresh data of the patterns of genetic variation at the PTP2 locus in naturally infected Apis mellifera colonies, by means of single genome amplification. This technique, designed to prevent the formation of chimeric haplotypes during polymerase chain reaction (PCR), provides more reliable estimates of the diversity levels and haplotype structure than standard PCR-cloning methods. Our results are consistent with low but significant rates of recombination in the history of the haplotypes detected: estimates of the population recombination rate are of the order of 30 and support recent evidence for unexpectedly high levels of variation of the parasites within honeybee colonies. These observations suggest the existence of a diploid stage at some point in the life cycle of this parasite and are relevant for our understanding of the dynamics of its expanding population.
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Affiliation(s)
- Tamara Gómez-Moracho
- Laboratorio de Patología Apícola, Centro Apícola Regional, JCCM, Marchamalo, 19180, Spain; Grupo de Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, 15782, Spain; Grupo de Xenómica Comparada de Parásitos Humanos, IDIS, Santiago de Compostela, Galicia, 15782, Spain
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