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Klocek D, Grybchuk D, Macedo DH, Galan A, Votýpka J, Schmid-Hempel R, Schmid-Hempel P, Yurchenko V, Kostygov AY. RNA viruses of Crithidia bombi, a parasite of bumblebees. J Invertebr Pathol 2023; 201:107991. [PMID: 37714407 DOI: 10.1016/j.jip.2023.107991] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/05/2023] [Accepted: 09/10/2023] [Indexed: 09/17/2023]
Abstract
Leishbuviridae (Bunyavirales) are a diverse monophyletic group of negative-sense single-stranded RNA virus infecting parasitic flagellates of the family Trypanosomatidae. The presence of RNA viruses in trypanosomatids can influence the virulence of the latter. Here, we performed a screening for viruses in Crithidia bombi - a common parasite of important pollinators Bombus spp. (bumblebees) that negatively affects its host in stressful conditions. The majority (8/10) of C. bombi isolates collected in Europe and North America were positive for a virus that we named Crithidia bombi leishbuvirus 1 with high conservation of amino acid sequences between isolates. The results of our comparative phylogenetic analyses of the trypanosomatids and their viruses suggest that the high mobility of bumblebees and frequent coinfections by different strains of C. bombi determine an extensive viral exchange between the latter.
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Affiliation(s)
- Donnamae Klocek
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
| | - Danyil Grybchuk
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia; Central European Institute of Technology, Masaryk University, 625 00 Brno, Czechia
| | - Diego H Macedo
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
| | - Arnau Galan
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
| | - Jan Votýpka
- Faculty of Science, Charles University, 128 00 Prague, Czechia; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
| | | | - Paul Schmid-Hempel
- Institute of Integrative Biology, ETH Zürich, 16 8092 Zürich, Switzerland
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia.
| | - Alexei Yu Kostygov
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia.
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Macedo DH, Grybchuk D, Režnarová J, Votýpka J, Klocek D, Yurchenko T, Ševčík J, Magri A, Dolinská MU, Záhonová K, Lukeš J, Servienė E, Jászayová A, Serva S, Malysheva MN, Frolov AO, Yurchenko V, Kostygov AY. Diversity of RNA viruses in the cosmopolitan monoxenous trypanosomatid Leptomonas pyrrhocoris. BMC Biol 2023; 21:191. [PMID: 37697369 PMCID: PMC10496375 DOI: 10.1186/s12915-023-01687-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 08/22/2023] [Indexed: 09/13/2023] Open
Abstract
BACKGROUND Trypanosomatids are parasitic flagellates well known because of some representatives infecting humans, domestic animals, and cultural plants. Many trypanosomatid species bear RNA viruses, which, in the case of human pathogens Leishmania spp., influence the course of the disease. One of the close relatives of leishmaniae, Leptomonas pyrrhocoris, has been previously shown to harbor viruses of the groups not documented in other trypanosomatids. At the same time, this species has a worldwide distribution and high prevalence in the natural populations of its cosmopolitan firebug host. It therefore represents an attractive model to study the diversity of RNA viruses. RESULTS We surveyed 106 axenic cultures of L. pyrrhocoris and found that 64 (60%) of these displayed 2-12 double-stranded RNA fragments. The analysis of next-generation sequencing data revealed four viral groups with seven species, of which up to five were simultaneously detected in a single trypanosomatid isolate. Only two of these species, a tombus-like virus and an Ostravirus, were earlier documented in L. pyrrhocoris. In addition, there were four new species of Leishbuviridae, the family encompassing trypanosomatid-specific viruses, and a new species of Qinviridae, the family previously known only from metatranscriptomes of invertebrates. Currently, this is the only qinvirus with an unambiguously determined host. Our phylogenetic inferences suggest reassortment in the tombus-like virus owing to the interaction of different trypanosomatid strains. Two of the new Leishbuviridae members branch early on the phylogenetic tree of this family and display intermediate stages of genomic segment reduction between insect Phenuiviridae and crown Leishbuviridae. CONCLUSIONS The unprecedented wide range of viruses in one protist species and the simultaneous presence of up to five viral species in a single Leptomonas pyrrhocoris isolate indicate the uniqueness of this flagellate. This is likely determined by the peculiarity of its firebug host, a highly abundant cosmopolitan species with several habits ensuring wide distribution and profuseness of L. pyrrhocoris, as well as its exposure to a wider spectrum of viruses compared to other trypanosomatids combined with a limited ability to transmit these viruses to its relatives. Thus, L. pyrrhocoris represents a suitable model to study the adoption of new viruses and their relationships with a protist host.
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Affiliation(s)
- Diego H Macedo
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
- University of Stockholm, Stockholm, Sweden
| | - Danyil Grybchuk
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
- Central European Institute of Technology, Masaryk University, 625 00, Brno, Czech Republic
| | - Jana Režnarová
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
- University Hospital in Ostrava, Ostrava, Czech Republic
| | - Jan Votýpka
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Faculty of Science, Charles University, 128 44, Prague, Czech Republic
| | - Donnamae Klocek
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
| | - Tatiana Yurchenko
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
| | - Jan Ševčík
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
| | - Alice Magri
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
- Department of Veterinary Medical Sciences, Alma Mater Studiorum - University of Bologna, Ozzano Dell'Emilia, 40064, Bologna, Italy
| | - Michaela Urda Dolinská
- Department of Epizootiology, Parasitology and Protection of One Health, University of Veterinary Medicine and Pharmacy, 041 81, Košice, Slovakia
| | - Kristína Záhonová
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Faculty of Science, Charles University, BIOCEV, 252 50, Vestec, Czech Republic
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Edmonton, AB, T6G 2R3, Canada
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Faculty of Sciences, University of South Bohemia, 370 05, České Budějovice, Czech Republic
| | - Elena Servienė
- Laboratory of Genetics, Institute of Botany, Nature Research Centre, 08412, Vilnius, Lithuania
| | - Alexandra Jászayová
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
- Institute of Parasitology, Slovak Academy of Sciences, 040 01, Košice, Slovakia
- University of Veterinary Medicine and Pharmacy, 041 81, Košice, Slovakia
| | - Saulius Serva
- Department of Biochemistry and Molecular Biology, Institute of Biosciences, Vilnius University, 10257, Vilnius, Lithuania
| | - Marina N Malysheva
- Zoological Institute of Russian Academy of Sciences, 199034, St. Petersburg, Russia
| | - Alexander O Frolov
- Zoological Institute of Russian Academy of Sciences, 199034, St. Petersburg, Russia
| | | | - Alexei Yu Kostygov
- Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic.
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Bartolomé C, Buendía-Abad M, Ornosa C, De la Rúa P, Martín-Hernández R, Higes M, Maside X. Bee Trypanosomatids: First Steps in the Analysis of the Genetic Variation and Population Structure of Lotmaria passim, Crithidia bombi and Crithidia mellificae. MICROBIAL ECOLOGY 2022; 84:856-867. [PMID: 34609533 PMCID: PMC9622509 DOI: 10.1007/s00248-021-01882-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
Trypanosomatids are among the most prevalent parasites in bees but, despite the fact that their impact on the colonies can be quite important and that their infectivity may potentially depend on their genotypes, little is known about the population diversity of these pathogens. Here we cloned and sequenced three non-repetitive single copy loci (DNA topoisomerase II, glyceraldehyde-3-phosphate dehydrogenase and RNA polymerase II large subunit, RPB1) to produce new genetic data from Crithidia bombi, C. mellificae and Lotmaria passim isolated from honeybees and bumblebees. These were analysed by applying population genetic tools in order to quantify and compare their variability within and between species, and to obtain information on their demography and population structure. The general pattern for the three species was that (1) they were subject to the action of purifying selection on nonsynonymous variants, (2) the levels of within species diversity were similar irrespective of the host, (3) there was evidence of recombination among haplotypes and (4) they showed no haplotype structuring according to the host. C. bombi exhibited the lowest levels of synonymous variation (πS= 0.06 ± 0.04 %) - and a mutation frequency distribution compatible with a population expansion after a bottleneck - that contrasted with the extensive polymorphism displayed by C. mellificae (πS= 2.24 ± 1.00 %), which likely has a more ancient origin. L. passim showed intermediate values (πS= 0.40 ± 0.28 %) and an excess of variants a low frequencies probably linked to the spread of this species to new geographical areas.
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Affiliation(s)
- Carolina Bartolomé
- Grupo de Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain.
- Instituto de Investigación Sanitaria de Santiago (IDIS), 15706, Santiago de Compostela, Galicia, Spain.
| | - María Buendía-Abad
- Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Laboratorio de Patología Apícola, Centro de Investigación Apícola y Agroambiental (CIAPA), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, 19180, Marchamalo, Spain
| | - Concepción Ornosa
- Departamento de Biodiversidad, Ecología y Evolución, Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Pilar De la Rúa
- Departamento de Zoología y Antropología Física, Facultad de Veterinaria, Universidad de Murcia, 30100, Murcia, Spain
| | - Raquel Martín-Hernández
- Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Laboratorio de Patología Apícola, Centro de Investigación Apícola y Agroambiental (CIAPA), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, 19180, Marchamalo, Spain
- Instituto de Recursos Humanos para la Ciencia y la Tecnología, Fundación Parque Científico Tecnológico de Albacete, 02006, Albacete, Spain
| | - Mariano Higes
- Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal (IRIAF), Laboratorio de Patología Apícola, Centro de Investigación Apícola y Agroambiental (CIAPA), Consejería de Agricultura de la Junta de Comunidades de Castilla-La Mancha, 19180, Marchamalo, Spain
| | - Xulio Maside
- Grupo de Medicina Xenómica, CIMUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain
- Instituto de Investigación Sanitaria de Santiago (IDIS), 15706, Santiago de Compostela, Galicia, Spain
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Effects of an alternative host on the prevalence and infection intensity of a bumble bee parasite. Parasitology 2022; 149:562-567. [PMID: 35067238 PMCID: PMC10090601 DOI: 10.1017/s003118202200004x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Several bee parasites are transmitted through flowers, and some of them can infect multiple host species. Given the shared use of flowers by bee species, parasites can potentially encounter multiple host species, which could affect the evolution of parasite virulence. We used the trypanosomatid parasite Crithidia bombi and its host, the common eastern bumble bee (Bombus impatiens), to explore the effect of infecting an alternative host, the alfalfa leaf-cutter bee (Megachile rotundata), on parasite infectivity and ability to replicate. We conducted a serial passage experiment on primary and alternative hosts, assessing infectivity and intensity of infection during five passes. Parasite cells from each pass through the alternative host were also used to infect a group of primary hosts. We found that serial passes through the alternative host increased infectivity, but there was no effect on intensity of infection. Interestingly, both the probability and intensity of infection on the primary host increased after serial passage through the alternative host. This increase in intensity of infection could be due to maladaptation after selection of new C. bombi strains has occurred in the alternative host. This study suggests that host switching has the potential to affect the adaptation of bee parasites to their hosts.
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Peacock L, Kay C, Farren C, Bailey M, Carrington M, Gibson W. Sequential production of gametes during meiosis in trypanosomes. Commun Biol 2021; 4:555. [PMID: 33976359 PMCID: PMC8113336 DOI: 10.1038/s42003-021-02058-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 03/24/2021] [Indexed: 02/03/2023] Open
Abstract
Meiosis is a core feature of eukaryotes that occurs in all major groups, including the early diverging excavates. In this group, meiosis and production of haploid gametes have been described in the pathogenic protist, Trypanosoma brucei, and mating occurs in the salivary glands of the insect vector, the tsetse fly. Here, we searched for intermediate meiotic stages among trypanosomes from tsetse salivary glands. Many different cell types were recovered, including trypanosomes in Meiosis I and gametes. Significantly, we found trypanosomes containing three nuclei with a 1:2:1 ratio of DNA contents. Some of these cells were undergoing cytokinesis, yielding a mononucleate gamete and a binucleate cell with a nuclear DNA content ratio of 1:2. This cell subsequently produced three more gametes in two further rounds of division. Expression of the cell fusion protein HAP2 (GCS1) was not confined to gametes, but also extended to meiotic intermediates. We propose a model whereby the two nuclei resulting from Meiosis I undergo asynchronous Meiosis II divisions with sequential production of haploid gametes.
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Affiliation(s)
- Lori Peacock
- School of Biological Sciences University of Bristol, Bristol, UK
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Chris Kay
- School of Biological Sciences University of Bristol, Bristol, UK
| | - Chloe Farren
- School of Biological Sciences University of Bristol, Bristol, UK
| | - Mick Bailey
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Wendy Gibson
- School of Biological Sciences University of Bristol, Bristol, UK.
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Gibson W. The sexual side of parasitic protists. Mol Biochem Parasitol 2021; 243:111371. [PMID: 33872659 DOI: 10.1016/j.molbiopara.2021.111371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/26/2021] [Accepted: 04/13/2021] [Indexed: 01/09/2023]
Abstract
Much of the vast evolutionary landscape occupied by Eukaryotes is dominated by protists. Though parasitism has arisen in many lineages, there are three main groups of parasitic protists of relevance to human and livestock health: the Apicomplexa, including the malaria parasite Plasmodium and coccidian pathogens of livestock such as Eimeria; the excavate flagellates, encompassing a diverse range of protist pathogens including trypanosomes, Leishmania, Giardia and Trichomonas; and the Amoebozoa, including pathogenic amoebae such as Entamoeba. These three groups represent separate, deep branches of the eukaryote tree, underlining their divergent evolutionary histories. Here, I explore what is known about sex in these three main groups of parasitic protists.
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Affiliation(s)
- Wendy Gibson
- School of Biological Sciences, Life Sciences Building, University of Bristol, Bristol, BS8 1TQ, United Kingdom.
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7
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Abstract
In this study, we sequenced and analyzed the genomes of 40 strains, in addition to the already-reported two type strains, of two Crithidia species infecting bumblebees in Alaska and Central Europe and demonstrated that different strains of Crithidia bombi and C. expoeki vary considerably in terms of single nucleotide polymorphisms and gene copy number. Based on the genomic structure, phylogenetic analyses, and the pattern of copy number variation, we confirmed the status of C. expoeki as a separate species. The Alaskan populations appear to be clearly separated from those of Central Europe. This pattern fits a scenario of rapid host-parasite coevolution, where the selective advantage of a given parasite strain is only temporary. This study provides helpful insights into possible scenarios of selection and diversification of trypanosomatid parasites.IMPORTANCE A group of trypanosomatid flagellates includes several well-studied medically and economically important parasites of vertebrates and plants. Nevertheless, the vast majority of trypanosomatids infect only insects (mostly flies and true bugs) and, because of that, has attracted little research attention in the past. Of several hundred trypanosomatid species, only four can infect bees (honeybees and bumblebees). Because of such scarcity, these parasites are severely understudied. We analyzed whole-genome information for a total of 42 representatives of bee-infecting trypanosomatids collected in Central Europe and Alaska from a population genetics point of view. Our data shed light on the evolution, selection, and diversification in this important group of trypanosomatid parasites.
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Recent advances in trypanosomatid research: genome organization, expression, metabolism, taxonomy and evolution. Parasitology 2018; 146:1-27. [PMID: 29898792 DOI: 10.1017/s0031182018000951] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Unicellular flagellates of the family Trypanosomatidae are obligatory parasites of invertebrates, vertebrates and plants. Dixenous species are aetiological agents of a number of diseases in humans, domestic animals and plants. Their monoxenous relatives are restricted to insects. Because of the high biological diversity, adaptability to dramatically different environmental conditions, and omnipresence, these protists have major impact on all biotic communities that still needs to be fully elucidated. In addition, as these organisms represent a highly divergent evolutionary lineage, they are strikingly different from the common 'model system' eukaryotes, such as some mammals, plants or fungi. A number of excellent reviews, published over the past decade, were dedicated to specialized topics from the areas of trypanosomatid molecular and cell biology, biochemistry, host-parasite relationships or other aspects of these fascinating organisms. However, there is a need for a more comprehensive review that summarizing recent advances in the studies of trypanosomatids in the last 30 years, a task, which we tried to accomplish with the current paper.
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Schmid-Hempel P, Aebi M, Barribeau S, Kitajima T, du Plessis L, Schmid-Hempel R, Zoller S. The genomes of Crithidia bombi and C. expoeki, common parasites of bumblebees. PLoS One 2018; 13:e0189738. [PMID: 29304093 PMCID: PMC5755769 DOI: 10.1371/journal.pone.0189738] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 11/30/2017] [Indexed: 11/19/2022] Open
Abstract
Trypanosomatids (Trypanosomatidae, Kinetoplastida) are flagellated protozoa containing many parasites of medical or agricultural importance. Among those, Crithidia bombi and C. expoeki, are common parasites in bumble bees around the world, and phylogenetically close to Leishmania and Leptomonas. They have a simple and direct life cycle with one host, and partially castrate the founding queens greatly reducing their fitness. Here, we report the nuclear genome sequences of one clone of each species, extracted from a field-collected infection. Using a combination of Roche 454 FLX Titanium, Pacific Biosciences PacBio RS, and Illumina GA2 instruments for C. bombi, and PacBio for C. expoeki, we could produce high-quality and well resolved sequences. We find that these genomes are around 32 and 34 MB, with 7,808 and 7,851 annotated genes for C. bombi and C. expoeki, respectively-which is somewhat less than reported from other trypanosomatids, with few introns, and organized in polycistronic units. A large fraction of genes received plausible functional support in comparison primarily with Leishmania and Trypanosoma. Comparing the annotated genes of the two species with those of six other trypanosomatids (C. fasciculata, L. pyrrhocoris, L. seymouri, B. ayalai, L. major, and T. brucei) shows similar gene repertoires and many orthologs. Similar to other trypanosomatids, we also find signs of concerted evolution in genes putatively involved in the interaction with the host, a high degree of synteny between C. bombi and C. expoeki, and considerable overlap with several other species in the set. A total of 86 orthologous gene groups show signatures of positive selection in the branch leading to the two Crithidia under study, mostly of unknown function. As an example, we examined the initiating glycosylation pathway of surface components in C. bombi, finding it deviates from most other eukaryotes and also from other kinetoplastids, which may indicate rapid evolution in the extracellular matrix that is involved in interactions with the host. Bumble bees are important pollinators and Crithidia-infections are suspected to cause substantial selection pressure on their host populations. These newly sequenced genomes provide tools that should help better understand host-parasite interactions in these pollinator pathogens.
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Affiliation(s)
| | - Markus Aebi
- Institute of Microbiology, ETH Zurich, Zürich, Switzerland
| | - Seth Barribeau
- Institute of Integrative Biology (IBZ), ETH Zurich, Zürich, Switzerland
| | | | - Louis du Plessis
- Institute of Integrative Biology (IBZ), ETH Zurich, Zürich, Switzerland
| | | | - Stefan Zoller
- Genetic Diversity Centre (GDC), ETH Zurich, Zürich, Switzerland
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Palmer-Young EC, Hogeboom A, Kaye AJ, Donnelly D, Andicoechea J, Connon SJ, Weston I, Skyrm K, Irwin RE, Adler LS. Context-dependent medicinal effects of anabasine and infection-dependent toxicity in bumble bees. PLoS One 2017; 12:e0183729. [PMID: 28832668 PMCID: PMC5568382 DOI: 10.1371/journal.pone.0183729] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 08/09/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Floral phytochemicals are ubiquitous in nature, and can function both as antimicrobials and as insecticides. Although many phytochemicals act as toxins and deterrents to consumers, the same chemicals may counteract disease and be preferred by infected individuals. The roles of nectar and pollen phytochemicals in pollinator ecology and conservation are complex, with evidence for both toxicity and medicinal effects against parasites. However, it remains unclear how consistent the effects of phytochemicals are across different parasite lineages and environmental conditions, and whether pollinators actively self-medicate with these compounds when infected. APPROACH Here, we test effects of the nectar alkaloid anabasine, found in Nicotiana, on infection intensity, dietary preference, and survival and performance of bumble bees (Bombus impatiens). We examined variation in the effects of anabasine on infection with different lineages of the intestinal parasite Crithidia under pollen-fed and pollen-starved conditions. RESULTS We found that anabasine did not reduce infection intensity in individual bees infected with any of four Crithidia lineages that were tested in parallel, nor did anabasine reduce infection intensity in microcolonies of queenless workers. In addition, neither anabasine nor its isomer, nicotine, was preferred by infected bees in choice experiments, and infected bees consumed less anabasine than did uninfected bees under no-choice conditions. Furthermore, anabasine exacerbated the negative effects of infection on bee survival and microcolony performance. Anabasine reduced infection in only one experiment, in which bees were deprived of pollen and post-pupal contact with nestmates. In this experiment, anabasine had antiparasitic effects in bees from only two of four colonies, and infected bees exhibited reduced-rather than increased-phytochemical consumption relative to uninfected bees. CONCLUSIONS Variation in the effect of anabasine on infection suggests potential modulation of tritrophic interactions by both host genotype and environmental variables. Overall, our results demonstrate that Bombus impatiens prefer diets without nicotine and anabasine, and suggest that the medicinal effects and toxicity of anabasine may be context dependent. Future research should identify the specific environmental and genotypic factors that determine whether nectar phytochemicals have medicinal or deleterious effects on pollinators.
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Affiliation(s)
- Evan C. Palmer-Young
- Organismic & Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Alison Hogeboom
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Alexander J. Kaye
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Dash Donnelly
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Jonathan Andicoechea
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Sara June Connon
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Ian Weston
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Kimberly Skyrm
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Rebecca E. Irwin
- Department of Biology, Dartmouth College, Hanover, New Hampshire, United States of America
- Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, United States of America
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11
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Palmer‐Young EC, Sadd BM, Adler LS. Evolution of resistance to single and combined floral phytochemicals by a bumble bee parasite. J Evol Biol 2017; 30:300-312. [PMID: 27783434 PMCID: PMC5324628 DOI: 10.1111/jeb.13002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 01/05/2023]
Abstract
Repeated exposure to inhibitory compounds can drive the evolution of resistance, which weakens chemical defence against antagonists. Floral phytochemicals in nectar and pollen have antimicrobial properties that can ameliorate infection in pollinators, but evolved resistance among parasites could diminish the medicinal efficacy of phytochemicals. However, multicompound blends, which occur in nectar and pollen, present simultaneous chemical challenges that may slow resistance evolution. We assessed evolution of resistance by the common bumble bee gut parasite Crithidia bombi to two floral phytochemicals, singly and combined, over 6 weeks (~100 generations) of chronic exposure. Resistance of C. bombi increased under single and combined phytochemical exposure, without any associated costs of reduced growth under phytochemical-free conditions. After 6 weeks' exposure, phytochemical concentrations that initially inhibited growth by > 50%, and exceeded concentrations in floral nectar, had minimal effects on evolved parasite lines. Unexpectedly, the phytochemical combination did not impede resistance evolution compared to single compounds. These results demonstrate that repeated phytochemical exposure, which could occur in homogeneous floral landscapes or with therapeutic phytochemical treatment of managed hives, can cause rapid evolution of resistance in pollinator parasites. We discuss possible explanations for submaximal phytochemical resistance in natural populations. Evolved resistance could diminish the antiparasitic value of phytochemical ingestion, weakening an important natural defence against infection.
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Affiliation(s)
| | - B. M. Sadd
- School of Biological SciencesIllinois State UniversityNormalILUSA
| | - L. S. Adler
- Department of BiologyUniversity of Massachusetts at AmherstAmherstMAUSA
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12
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Marxer M, Vollenweider V, Schmid-Hempel P. Insect antimicrobial peptides act synergistically to inhibit a trypanosome parasite. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150302. [PMID: 27160603 PMCID: PMC4874398 DOI: 10.1098/rstb.2015.0302] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2016] [Indexed: 11/12/2022] Open
Abstract
The innate immune system provides protection from infection by producing essential effector molecules, such as antimicrobial peptides (AMPs) that possess broad-spectrum activity. This is also the case for bumblebees, Bombus terrestris, when infected by the trypanosome, Crithidia bombi Furthermore, the expressed mixture of AMPs varies with host genetic background and infecting parasite strain (genotype). Here, we used the fact that clones of C. bombi can be cultivated and kept as strains in medium to test the effect of various combinations of AMPs on the growth rate of the parasite. In particular, we used pairwise combinations and a range of physiological concentrations of three AMPs, namely Abaecin, Defensin and Hymenoptaecin, synthetized from the respective genomic sequences. We found that these AMPs indeed suppress the growth of eight different strains of C. bombi, and that combinations of AMPs were typically more effective than the use of a single AMP alone. Furthermore, the most effective combinations were rarely those consisting of maximum concentrations. In addition, the AMP combination treatments revealed parasite strain specificity, such that strains varied in their sensitivity towards the same mixtures. Hence, variable expression of AMPs could be an alternative strategy to combat highly variable infections.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'.
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Affiliation(s)
- Monika Marxer
- ETH Zurich, Institute of Integrative Biology (IBZ), Universitätsstrasse 16, 8092 Zürich, Switzerland
| | - Vera Vollenweider
- ETH Zurich, Institute of Integrative Biology (IBZ), Universitätsstrasse 16, 8092 Zürich, Switzerland
| | - Paul Schmid-Hempel
- ETH Zurich, Institute of Integrative Biology (IBZ), Universitätsstrasse 16, 8092 Zürich, Switzerland
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Genome of Leptomonas pyrrhocoris: a high-quality reference for monoxenous trypanosomatids and new insights into evolution of Leishmania. Sci Rep 2016; 6:23704. [PMID: 27021793 PMCID: PMC4810370 DOI: 10.1038/srep23704] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 02/24/2016] [Indexed: 01/22/2023] Open
Abstract
Many high-quality genomes are available for dixenous (two hosts) trypanosomatid species of the genera Trypanosoma, Leishmania, and Phytomonas, but only fragmentary information is available for monoxenous (single-host) trypanosomatids. In trypanosomatids, monoxeny is ancestral to dixeny, thus it is anticipated that the genome sequences of the key monoxenous parasites will be instrumental for both understanding the origin of parasitism and the evolution of dixeny. Here, we present a high-quality genome for Leptomonas pyrrhocoris, which is closely related to the dixenous genus Leishmania. The L. pyrrhocoris genome (30.4 Mbp in 60 scaffolds) encodes 10,148 genes. Using the L. pyrrhocoris genome, we pinpointed genes gained in Leishmania. Among those genes, 20 genes with unknown function had expression patterns in the Leishmania mexicana life cycle suggesting their involvement in virulence. By combining differential expression data for L. mexicana, L. major and Leptomonas seymouri, we have identified several additional proteins potentially involved in virulence, including SpoU methylase and U3 small nucleolar ribonucleoprotein IMP3. The population genetics of L. pyrrhocoris was also addressed by sequencing thirteen strains of different geographic origin, allowing the identification of 1,318 genes under positive selection. This set of genes was significantly enriched in components of the cytoskeleton and the flagellum.
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Liaisons dangereuses: sexual recombination among pathogenic trypanosomes. Res Microbiol 2015; 166:459-66. [DOI: 10.1016/j.resmic.2015.05.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/18/2015] [Accepted: 05/18/2015] [Indexed: 11/20/2022]
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Mating compatibility in the parasitic protist Trypanosoma brucei. Parasit Vectors 2014; 7:78. [PMID: 24559099 PMCID: PMC3936861 DOI: 10.1186/1756-3305-7-78] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 02/17/2014] [Indexed: 12/30/2022] Open
Abstract
Background Genetic exchange has been described in several kinetoplastid parasites, but the most well-studied mating system is that of Trypanosoma brucei, the causative organism of African sleeping sickness. Sexual reproduction takes place in the salivary glands (SG) of the tsetse vector and involves meiosis and production of haploid gametes. Few genetic crosses have been carried out to date and consequently there is little information about the mating compatibility of different trypanosomes. In other single-celled eukaryotes, mating compatibility is typically determined by a system of two or more mating types (MT). Here we investigated the MT system in T. brucei. Methods We analysed a large series of F1, F2 and back crosses by pairwise co-transmission of red and green fluorescent cloned cell lines through experimental tsetse flies. To analyse each cross, trypanosomes were cloned from fly SG containing a mixture of both parents, and genotyped by microsatellites and molecular karyotype. To investigate mating compatibility at the level of individual cells, we directly observed the behaviour of SG-derived gametes in intra- or interclonal mixtures of red and green fluorescent trypanosomes ex vivo. Results Hybrid progeny were found in all F1 and F2 crosses and most of the back crosses. The success of individual crosses was highly variable as judged by the number of hybrid clones produced, suggesting a range of mating compatibilities among F1 progeny. As well as hybrids, large numbers of recombinant genotypes resulting from intraclonal mating (selfers) were found in some crosses. In ex vivo mixtures, red and green fluorescent trypanosome gametes were observed to pair up and interact via their flagella in both inter- and intraclonal combinations. While yellow hybrid trypanosomes were frequently observed in interclonal mixtures, such evidence of cytoplasmic exchange was rare in the intraclonal mixtures. Conclusions The outcomes of individual crosses, particularly back crosses, were variable in numbers of both hybrid and selfer clones produced, and do not readily fit a simple two MT model. From comparison of the behaviour of trypanosome gametes in inter- and intraclonal mixtures, we infer that mating compatibility is controlled at the level of gamete fusion.
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Schmid-Hempel R, Eckhardt M, Goulson D, Heinzmann D, Lange C, Plischuk S, Escudero LR, Salathé R, Scriven JJ, Schmid-Hempel P. The invasion of southern South America by imported bumblebees and associated parasites. J Anim Ecol 2014; 83:823-37. [PMID: 24256429 DOI: 10.1111/1365-2656.12185] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 11/18/2013] [Indexed: 01/13/2023]
Abstract
The Palaearctic Bombus ruderatus (in 1982/1983) and Bombus terrestris (1998) have both been introduced into South America (Chile) for pollination purposes. We here report on the results of sampling campaigns in 2004, and 2010-2012 showing that both species have established and massively expanded their range. Bombus terrestris, in particular, has spread by some 200 km year(-1) and had reached the Atlantic coast in Argentina by the end of 2011. Both species, and especially B. terrestris, are infected by protozoan parasites that seem to spread along with the imported hosts and spillover to native species. Genetic analyses by polymorphic microsatellite loci suggest that the host population of B. terrestris is genetically diverse, as expected from a large invading founder population, and structured through isolation by distance. Genetically, the populations of the trypanosomatid parasite, Crithidia bombi, sampled in 2004 are less diverse, and distinct from the ones sampled later. Current C. bombi populations are highly heterozygous and also structured through isolation by distance correlating with the genetic distances of B. terrestris, suggesting the latter's expansion to be a main structuring factor for the parasite. Remarkably, wherever B. terrestris spreads, the native Bombus dahlbomii disappears although the reasons remain unclear. Our ecological and genetic data suggest a major invasion event that is currently unfolding in southern South America with disastrous consequences for the native bumblebee species.
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Affiliation(s)
- Regula Schmid-Hempel
- ETH Zürich, Institute of Integrative Biology (IBZ), ETH-Zentrum CHN, Universitätsstrasse 16, CH-8092, Zürich, Switzerland
| | - Michael Eckhardt
- ETH Zürich, Institute of Integrative Biology (IBZ), ETH-Zentrum CHN, Universitätsstrasse 16, CH-8092, Zürich, Switzerland
| | - David Goulson
- Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Daniel Heinzmann
- ETH Zürich, Institute of Integrative Biology (IBZ), ETH-Zentrum CHN, Universitätsstrasse 16, CH-8092, Zürich, Switzerland
| | - Carlos Lange
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE), CCT La Plata CONICET-UNLP, Comisión de Investigaciones Cientificas de la provincia de Buenos Aires (CICPBA), Calle 2 # 584, 1900, La Plata, Argentina
| | - Santiago Plischuk
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE), CCT La Plata CONICET-UNLP, Comisión de Investigaciones Cientificas de la provincia de Buenos Aires (CICPBA), Calle 2 # 584, 1900, La Plata, Argentina
| | - Luisa R Escudero
- Instituto de Biología, Pontificia Universita Católica de Valparaíso, Avda. Brasil, 2950, Valparaíso, Chile
| | - Rahel Salathé
- ETH Zürich, Institute of Integrative Biology (IBZ), ETH-Zentrum CHN, Universitätsstrasse 16, CH-8092, Zürich, Switzerland
| | - Jessica J Scriven
- Biological and Environmental Sciences, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Paul Schmid-Hempel
- ETH Zürich, Institute of Integrative Biology (IBZ), ETH-Zentrum CHN, Universitätsstrasse 16, CH-8092, Zürich, Switzerland
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Cisarovsky G, Schmid-Hempel P. Few colonies of the host Bombus terrestris disproportionately affect the genetic diversity of its parasite, Crithidia bombi. INFECTION GENETICS AND EVOLUTION 2014; 21:192-7. [DOI: 10.1016/j.meegid.2013.11.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 10/30/2013] [Accepted: 11/01/2013] [Indexed: 11/28/2022]
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Tibayrenc M, Ayala FJ. Reproductive clonality of pathogens: a perspective on pathogenic viruses, bacteria, fungi, and parasitic protozoa. Proc Natl Acad Sci U S A 2012; 109:E3305-13. [PMID: 22949662 PMCID: PMC3511763 DOI: 10.1073/pnas.1212452109] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We propose that clonal evolution in micropathogens be defined as restrained recombination on an evolutionary scale, with genetic exchange scarce enough to not break the prevalent pattern of clonal population structure, a definition already widely used for all kinds of pathogens, although not clearly formulated by many scientists and rejected by others. The two main manifestations of clonal evolution are strong linkage disequilibrium (LD) and widespread genetic clustering ("near-clading"). We hypothesize that this pattern is not mainly due to natural selection, but originates chiefly from in-built genetic properties of pathogens, which could be ancestral and could function as alternative allelic systems to recombination genes ("clonality/sexuality machinery") to escape recombinational load. The clonal framework of species of pathogens should be ascertained before any analysis of biomedical phenotypes (phylogenetic character mapping). In our opinion, this model provides a conceptual framework for the population genetics of any micropathogen.
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Affiliation(s)
- Michel Tibayrenc
- Maladies Infectieuses et Vecteurs Ecologie, Génétique, Evolution et Contrôle, Institut de Rercherche pour le Développement 224, Centre National de la Recherche Scientifique 5290, Universités Montpellier 1 and 2, 34394 Montpellier Cedex 5, France; and
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697
| | - Francisco J. Ayala
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697
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Salathé R, Tognazzo M, Schmid-Hempel R, Schmid-Hempel P. Probing mixed-genotype infections I: extraction and cloning of infections from hosts of the trypanosomatid Crithidia bombi. PLoS One 2012; 7:e49046. [PMID: 23155449 PMCID: PMC3498296 DOI: 10.1371/journal.pone.0049046] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 10/03/2012] [Indexed: 11/25/2022] Open
Abstract
We here present an efficient, precise and reliable method to isolate and cultivate healthy and viable single Crithidia bombi cells from bumblebee faeces using flow cytometry. We report a precision of >99% in obtaining single trypanosomatid cells for further culture and analysis (“cloning”). In the study, we have investigated the use of different liquid media to cultivate C. bombi and present an optimal medium for obtaining viable clones from all tested, infected host donors. We show that this method can be applied to genotype a collection of clones from natural infections. Furthermore, we show how to cryo-preserve C. bombi cells to be revived to become infective clones after at least 4 years of storage. Considering the high prevalence of infections in natural populations, our method provides a powerful tool in studying the level and diversity of these infections, and thus enriches the current methodology for the studies of complex host-parasite interactions.
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Affiliation(s)
- Rahel Salathé
- Institute of Integrative Biology (IBZ), ETH Zürich, Zürich, Switzerland
- * E-mail: (RS); (PSH)
| | | | | | - Paul Schmid-Hempel
- Institute of Integrative Biology (IBZ), ETH Zürich, Zürich, Switzerland
- * E-mail: (RS); (PSH)
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20
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Probing mixed-genotype infections II: high multiplicity in natural infections of the trypanosomatid, Crithidia bombi, in its host, Bombus spp. PLoS One 2012; 7:e49137. [PMID: 23145099 PMCID: PMC3493493 DOI: 10.1371/journal.pone.0049137] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 10/03/2012] [Indexed: 11/30/2022] Open
Abstract
Mixed-genotype infections have major consequences for many essential elements of host-parasite interactions. With genetic exchange between co-infecting parasite genotypes increased diversity among parasite offspring and the emergence of novel genotypes from infected hosts is possible. We here investigated mixed- genotype infections using the host, Bombus spp. and its trypanosome parasite Crithidia bombi as our study case. The natural infections of C. bombi were genotyped with a novel method for a representative sample of workers and spring queens in Switzerland. We found that around 60% of all infected hosts showed mixed-genotype infections with an average of 2.47±0.22 (S.E.) and 3.65±1.02 genotypes per worker or queen, respectively. Queens, however, harboured up to 29 different genotypes. Based on the genotypes of co-infecting strains, these could be putatively assigned to either ‘primary’ and ‘derived’ genotypes - the latter resulting from genetic exchange among the primary genotypes. High genetic relatedness among co-infecting derived but not primary genotypes supported this scenario. Co-infection in queens seems to be a major driver for the diversity of genotypes circulating in host populations.
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Popp M, Erler S, Lattorff HMG. Seasonal variability of prevalence and occurrence of multiple infections shape the population structure of Crithidia bombi, an intestinal parasite of bumblebees (Bombus spp.). Microbiologyopen 2012; 1:362-72. [PMID: 23233373 PMCID: PMC3535382 DOI: 10.1002/mbo3.35] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 07/27/2012] [Accepted: 08/06/2012] [Indexed: 11/07/2022] Open
Abstract
Ergonomic growth phases of annual social insect societies strongly influence horizontally transmitted parasites. Herein, we focused on the impact of temporal changes in host demography on the population structure of a horizontally transmitted parasite. Seasonal fluctuations in prevalence and the occurrence of multiple infections of the gut parasite Crithidia bombi were analyzed in repeatedly sampled populations of two common bumblebee (Bombus spp.) species. Prevalence of C. bombi was greatest in the middle of the foraging season and coincided with the maximal occurrence of multiple infections. Both decline later in the season. The genetic structure of the parasite population also showed strong seasonal fluctuations with a drastic decline in effective population size and an increase in linkage disequilibrium when infection rates were highest. These effects are mainly attributable to significant changes in parasite allele frequencies leading to selection of specific alleles and increasing the frequency of homozygote genotypes in the middle of the season. Within host, competition between parasite genotypes might explain the observed pattern leading to selection of these alleles, and thus a boost of homozygote genotypes in the middle of the season. Toward the end of the season, selection appears to relax and we observed a recovery in linkage equilibrium, as well as an increase in effective population size. This might be explained by genetic exchange in these trypanosomes in natural populations.
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Affiliation(s)
- Mario Popp
- Institut für Biologie, Molekulare Ökologie, Martin-Luther-Universität Halle-Wittenberg, Hoher Weg 4, 06099, Halle (Saale), Germany.
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Erler S, Popp M, Wolf S, Lattorff HMG. Sex, horizontal transmission, and multiple hosts prevent local adaptation of Crithidia bombi, a parasite of bumblebees (Bombus spp.). Ecol Evol 2012; 2:930-40. [PMID: 22837838 PMCID: PMC3399159 DOI: 10.1002/ece3.250] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 02/28/2012] [Accepted: 02/29/2012] [Indexed: 12/04/2022] Open
Abstract
Local adaptation within host-parasite systems can evolve by several non-exclusive drivers (e.g., host species-genetic adaptation; ecological conditions-ecological adaptation, and time-temporal adaptation). Social insects, especially bumblebees, with an annual colony life history not only provide an ideal system to test parasite transmission within and between different host colonies, but also parasite adaptation to specific host species and environments. Here, we study local adaptation in a multiple-host parasite characterized by high levels of horizontal transmission. Crithidia bombi occurs as a gut parasite in several bumblebee species. Parasites were sampled from five different host species in two subsequent years. Population genetic tools were used to test for the several types of adaptation. Although we found no evidence for local adaptation of the parasite toward host species, there was a slight temporal differentiation of the parasite populations, which might have resulted from severe bottlenecks during queen hibernation. Parasite populations were in Hardy-Weinberg equilibrium and showed no signs of linkage disequilibrium suggesting that sexual reproduction is an alternative strategy in this otherwise clonal parasite. Moreover, high levels of multiple infections were found, which might facilitate sexual genetic exchange. The detection of identical clones in different host species suggested that horizontal transmission occurs between host species and underpins the lack of host-specific adaptation.
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Affiliation(s)
- Silvio Erler
- Institut für Biologie, Molekulare Ökologie, Martin-Luther-Universität Halle-WittenbergHoher Weg 4, 06099 Halle (Saale), Germany
- Present address: Departamentul de Tehnologii Apicole şi Sericicole, Universitatea de Ştiinţe Agricole şi Medicină VeterinarăCalea Mănăştur 3–5, 400372, Cluj-Napoca, Romania
| | - Mario Popp
- Institut für Biologie, Molekulare Ökologie, Martin-Luther-Universität Halle-WittenbergHoher Weg 4, 06099 Halle (Saale), Germany
| | - Stephan Wolf
- Institut für Biologie, Molekulare Ökologie, Martin-Luther-Universität Halle-WittenbergHoher Weg 4, 06099 Halle (Saale), Germany
- Present address: Department of Plant and Invertebrate Ecology, Rothamsted ResearchAL5 2JQ Harpenden, United Kingdom
| | - H Michael G Lattorff
- Institut für Biologie, Molekulare Ökologie, Martin-Luther-Universität Halle-WittenbergHoher Weg 4, 06099 Halle (Saale), Germany
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Koch H, Schmid-Hempel P. Gut microbiota instead of host genotype drive the specificity in the interaction of a natural host-parasite system. Ecol Lett 2012; 15:1095-103. [PMID: 22765311 DOI: 10.1111/j.1461-0248.2012.01831.x] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 05/31/2012] [Accepted: 06/14/2012] [Indexed: 01/15/2023]
Abstract
Specific interactions between parasite genotypes and host genotypes (G(p) × G(h)) are commonly found in invertebrate systems, but are largely lacking a mechanistic explanation. The genotype of invertebrate hosts can be complemented by the genomes of microorganisms living on or within the host ('microbiota'). We investigated whether the bacterial gut microbiota of bumble bees (Bombus terrestris) can account for the specificity of interactions between individuals from different colonies (previously taken as host genotype proxy) and genotypes of the parasite Crithidia bombi. For this, we transplanted the microbiota between individuals of six colonies. Both the general infection load and the specific success of different C. bombi genotypes were mostly driven by the microbiota, rather than by worker genotype. Variation in gut microbiota can therefore be responsible for specific immune phenotypes and the evolution of gut parasites may be driven by interactions with 'microbiota types' as well as with host genotypes.
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Affiliation(s)
- Hauke Koch
- Institute of Integrative Biology (IBZ), ETH Zurich, ETH-Zentrum CHN, Zurich, Switzerland.
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Ruiz-González MX, Bryden J, Moret Y, Reber-Funk C, Schmid-Hempel P, Brown MJF. DYNAMIC TRANSMISSION, HOST QUALITY, AND POPULATION STRUCTURE IN A MULTIHOST PARASITE OF BUMBLEBEES. Evolution 2012; 66:3053-66. [DOI: 10.1111/j.1558-5646.2012.01655.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ulrich Y, Schmid-Hempel P. Host modulation of parasite competition in multiple infections. Proc Biol Sci 2012; 279:2982-9. [PMID: 22492064 DOI: 10.1098/rspb.2012.0474] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Parasite diversity is a constant challenge to host immune systems and has important clinical implications, but factors underpinning its emergence and maintenance are still poorly understood. Hosts typically harbour multiple parasite genotypes that share both host resources and immune responses. Parasite diversity is thus shaped not only by resource competition between co-infecting parasites but also by host-driven immune-mediated competition. We investigated these effects in an insect-trypanosome system, combining in vivo and in vitro single and double inoculations. In vivo, a non-pathogenic, general immune challenge was used to manipulate host immune condition and resulted in a reduced ability of hosts to defend against a subsequent exposure to the trypanosome parasites, illustrating the costs of immune activation. The associated increase in available host space benefited the weaker parasite strains of each pair as much as the otherwise more competitive strains, resulting in more frequent multiple infections in immune-challenged hosts. In vitro assays showed that in the absence of a host, overall parasite diversity was minimal because the outcome of competition was virtually fixed and resulted in strain extinction. Altogether, this shows that parasite competition is largely host-mediated and suggests a role for host immune condition in the maintenance of parasite diversity.
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Affiliation(s)
- Yuko Ulrich
- Institute of Integrative Biology (IBZ), ETH Zürich, Universitätsstrasse 16, 8092 Zürich, Switzerland.
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Multifaceted population structure and reproductive strategy in Leishmania donovani complex in one Sudanese village. PLoS Negl Trop Dis 2011; 5:e1448. [PMID: 22206035 PMCID: PMC3243727 DOI: 10.1371/journal.pntd.0001448] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 11/06/2011] [Indexed: 11/19/2022] Open
Abstract
Leishmania species of the subgenus Leishmania and especially L. donovani are responsible for a large proportion of visceral leishmaniasis cases. The debate on the mode of reproduction and population structure of Leishmania parasites remains opened. It has been suggested that Leishmania parasites could alternate different modes of reproduction, more particularly clonality and frequent recombinations either between related individuals (endogamy) or between unrelated individuals (outcrossing) within strongly isolated subpopulations. To determine whether this assumption is generalized to other species, a population genetics analysis within Leishmania donovani complex strains was conducted within a single village. The results suggest that a mixed-mating reproduction system exists, an important heterogeneity of subsamples and the coexistence of several genetic entities in Sudanese L. donovani. Indeed, results showed significant genetic differentiation between the three taxa (L. donovani, L. infantum and L. archibaldi) and between the human or canine strains of such taxa, suggesting that there may be different imbricated transmission cycles involving either dogs or humans. Results also are in agreement with an almost strict specificity of L. donovani stricto sensu to human hosts. This empirical study demonstrates the complexity of population structure in the genus Leishmania and the need to pursue such kind of analyses at the smallest possible spatio-temporal and ecological scales. Leishmaniases are a serious public health problem, especially in developing countries, caused by Leishmania parasites and transmitted by sandfly bites. More information is needed on the population biology of these pathogens for diagnostic and epidemiological inquiries and for drug and vaccine elaboration. For studies dealing with the population genetics, exploring the genetic patterns of such organisms at microgeographic scales is fundamental. In this context, we made a population genetic study, based on 20 microsatellite loci, on 61 strains of Leishmania donovani complex collected in a Sudanese village, Babar El Fugara, during the epidemic of 1996–2000. Results showed that considering the whole sample as a single population was not adequate because of the coexistence of several genetic entities and a genetic differentiation between the human or canine strains. In addition, our findings suggested that clonality may have a strong impact on the L. donovani complex, unlike other Leishmania species. This study demonstrates the need to pursue population genetics studies in Leishmania species from sampling designs that control maximum possible confounding factors and to elaborate such kinds of analyses at the smallest possible spatio-temporal and ecological scales.
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Salathé RM, Schmid-Hempel P. The genotypic structure of a multi-host bumblebee parasite suggests a role for ecological niche overlap. PLoS One 2011; 6:e22054. [PMID: 21853023 PMCID: PMC3154203 DOI: 10.1371/journal.pone.0022054] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 06/16/2011] [Indexed: 01/09/2023] Open
Abstract
The genotypic structure of parasite populations is an important determinant of ecological and evolutionary dynamics of host-parasite interactions with consequences for pest management and disease control. Genotypic structure is especially interesting where multiple hosts co-exist and share parasites. We here analyze the natural genotypic distribution of Crithidia bombi, a trypanosomatid parasite of bumblebees (Bombus spp.), in two ecologically different habitats over a time period of three years. Using an algorithm to reconstruct genotypes in cases of multiple infections, and combining these with directly identified genotypes from single infections, we find a striking diversity of infection for both data sets, with almost all multi-locus genotypes being unique, and are inferring that around half of the total infections are resulting from multiple strains. Our analyses further suggest a mixture of clonality and sexuality in natural populations of this parasite species. Finally, we ask whether parasite genotypes are associated with host species (the phylogenetic hypothesis) or whether ecological factors (niche overlap in flower choice) shape the distribution of parasite genotypes (the ecological hypothesis). Redundancy analysis demonstrates that in the region with relatively high parasite prevalence, both host species identity and niche overlap are equally important factors shaping the distribution of parasite strains, whereas in the region with lower parasite prevalence, niche overlap more strongly contributes to the distribution observed. Overall, our study underlines the importance of ecological factors in shaping the natural dynamics of host-parasite systems.
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Affiliation(s)
- Rahel M Salathé
- Institute of Integrative Biology (IBZ), ETH Zürich, Zürich, Switzerland.
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