1
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Lehman SS, Verhoeve VI, Driscoll TP, Beckmann JF, Gillespie JJ. Metagenome diversity illuminates the origins of pathogen effectors. mBio 2024; 15:e0075923. [PMID: 38564675 PMCID: PMC11077975 DOI: 10.1128/mbio.00759-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 02/12/2024] [Indexed: 04/04/2024] Open
Abstract
Recent metagenome-assembled genome (MAG) analyses have profoundly impacted Rickettsiology systematics. The discovery of basal lineages (novel families Mitibacteraceae and Athabascaceae) with predicted extracellular lifestyles exposed an evolutionary timepoint for the transition to host dependency, which seemingly occurred independent of mitochondrial evolution. Notably, these basal rickettsiae carry the Rickettsiales vir homolog (rvh) type IV secretion system and purportedly use rvh to kill congener microbes rather than parasitize host cells as described for later-evolving rickettsial pathogens. MAG analysis also substantially increased diversity for the genus Rickettsia and delineated a sister lineage (the novel genus Tisiphia) that stands to inform on the emergence of human pathogens from protist and invertebrate endosymbionts. Herein, we probed Rickettsiales MAG and genomic diversity for the distribution of Rickettsia rvh effectors to ascertain their origins. A sparse distribution of most Rickettsia rvh effectors outside of Rickettsiaceae lineages illuminates unique rvh evolution from basal extracellular species and other rickettsial families. Remarkably, nearly every effector was found in multiple divergent forms with variable architectures, indicating profound roles for gene duplication and recombination in shaping effector repertoires in Rickettsia pathogens. Lateral gene transfer plays a prominent role in shaping the rvh effector landscape, as evinced by the discovery of many effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchange between Rickettsia and Legionella species. Our study exemplifies how MAGs can yield insight into pathogen effector origins, particularly how effector architectures might become tailored to the discrete host cell functions of different eukaryotic hosts.IMPORTANCEWhile rickettsioses are deadly vector-borne human diseases, factors distinguishing Rickettsia pathogens from the innumerable bevy of environmental rickettsial endosymbionts remain lacking. Recent metagenome-assembled genome (MAG) studies revealed evolutionary timepoints for rickettsial transitions to host dependency. The rvh type IV secretion system was likely repurposed from congener killing in basal extracellular species to parasitizing host cells in later-evolving pathogens. Our analysis of MAG diversity for over two dozen rvh effectors unearthed their presence in some non-pathogens. However, most effectors were found in multiple divergent forms with variable architectures, indicating gene duplication and recombination-fashioned effector repertoires of Rickettsia pathogens. Lateral gene transfer substantially shaped pathogen effector arsenals, evinced by the discovery of effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchanges between Rickettsia and Legionella species. Our study exemplifies how MAGs yield insight into pathogen effector origins and evolutionary processes tailoring effectors to eukaryotic host cell biology.
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Affiliation(s)
- Stephanie S. Lehman
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Victoria I. Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Timothy P. Driscoll
- Department of Biology, West Virginia University, Morgantown, West Virginia, USA
| | - John F. Beckmann
- Department of Microbiology and Immunology, University of South Alabama, Mobile, Alabama, USA
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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2
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Murphy RO, Beckmann JF. Using Baker's Yeast to Determine Functions of Novel Wolbachia (and Other Prokaryotic) Effectors. Methods Mol Biol 2024; 2739:321-336. [PMID: 38006560 DOI: 10.1007/978-1-0716-3553-7_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
Yeasts are single-celled eukaryotic organisms classified as fungi, mostly in the phylum Ascomycota. Of about 1500 named species, Saccharomyces cerevisiae, also known as baker's yeast, domesticated by humans in the context of cooking and brewing, is a profound genetic tool for exploring functions of novel effector proteins from Wolbachia and prokaryotes in general. Wolbachia is a Gram-negative alpha-proteobacterium that infects up to ~75% of all insects as an obligate intracellular microbe (Jeyaprakash A, Hoy MA, Insect Mol Biol 9:393-405, 2000). Wolbachia's lifestyle presents unique challenges for researchers. Wolbachia cannot be axenically cultured and has never been genetically manipulated. Furthermore, many Wolbachia genes have no known function or well-annotated orthologs in other genomes. Yet given the effects of Wolbachia on host phenotypes, which have considerable practical applications for pest control, they undoubtedly involve secreted effector proteins that interact with host gene products. Studying these effectors is challenging with Wolbachia's current genetic limitations. However, some of the constraints to working with Wolbachia can be overcome by expressing candidate proteins in S. cerevisiae. This approach capitalizes on yeast's small genome (~6500 genes), typical eukaryotic cellular organization, and the sophisticated suite of genetic tools available for its manipulation in culture. Thus, yeast can serve as a powerful mock eukaryotic host background to study Wolbachia effector function. Specifically, yeast is used for recombinant protein expression, drug discovery, protein localization studies, protein interaction mapping (yeast two-hybrid system), modeling chromosomal evolution, and examining interactions between proteins responsible for complex phenotypes in less tractable prokaryotic systems. As an example, the paired genes responsible for Wolbachia-mediated cytoplasmic incompatibility (CI) encode novel proteins with limited homology to other known proteins, and no obvious function. This article details how S. cerevisiae was used as an initial staging ground to explore the molecular basis of one of Wolbachia's trademark phenotypes (CI).
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Affiliation(s)
- Richard O Murphy
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - John F Beckmann
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA.
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3
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Davison HR, Crozier J, Pirro S, Kampen H, Werner D, Hurst GDD. 'Candidatus Tisiphia' is a widespread Rickettsiaceae symbiont in the mosquito Anopheles plumbeus (Diptera: Culicidae). Environ Microbiol 2023; 25:3064-3074. [PMID: 37658745 PMCID: PMC10947512 DOI: 10.1111/1462-2920.16486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 08/08/2023] [Indexed: 09/05/2023]
Abstract
Symbiotic bacteria can alter host biology by providing protection from natural enemies, or alter reproduction or vectoral competence. Symbiont-linked control of vector-borne disease in Anopheles has been hampered by a lack of symbioses that can establish stable vertical transmission in the host. Previous screening found the symbiont 'Candidatus Tisiphia' in Anopheles plumbeus, an aggressive biter and potential secondary vector of malaria parasites and West Nile virus. We screened samples collected over 10-years across Germany and used climate databases to assess environmental influence on incidence. We observed a 95% infection rate, and that the frequency of infection did not fluctuate with broad environmental factors. Maternal inheritance is indicated by presence in the ovaries through FISH microscopy. Finally, we assembled a high-quality 1.6 Mbp draft genome of 'Ca. Tisiphia' to explore its phylogeny and potential metabolic competence. The infection is closely related to strains found in Culicoides biting midges and shows similar patterns of metabolism, providing no evidence of the capacity to synthesize B-vitamins. This infection offers avenues for onward research in anopheline mosquito symbioses. Additionally, it provides future opportunity to study the impact of 'Ca. Tisiphia' on natural and transinfected hosts, especially in relation to reproductive fitness and vectorial competence and capacity.
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Affiliation(s)
- Helen R. Davison
- Institute of Infection, Veterinary and Ecological Sciences (IVES)University of LiverpoolLiverpoolUK
| | - Jessica Crozier
- Institute of Infection, Veterinary and Ecological Sciences (IVES)University of LiverpoolLiverpoolUK
| | | | - Helge Kampen
- Institute of Infectology (IMED)Friedrich‐Loeffler‐Institut, Federal Research Institute for Animal HealthGreifswaldIsle of RiemsGermany
| | - Doreen Werner
- Land Use and GovernanceLeibniz Centre for Agricultural Landscape Research (ZALF)MünchebergGermany
| | - Gregory D. D. Hurst
- Institute of Infection, Veterinary and Ecological Sciences (IVES)University of LiverpoolLiverpoolUK
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4
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Harumoto T. Self-stabilization mechanism encoded by a bacterial toxin facilitates reproductive parasitism. Curr Biol 2023; 33:4021-4029.e6. [PMID: 37673069 DOI: 10.1016/j.cub.2023.08.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/30/2023] [Accepted: 08/10/2023] [Indexed: 09/08/2023]
Abstract
A wide variety of maternally transmitted endosymbionts in insects are associated with reproductive parasitism, whereby they interfere with host reproduction to increase the ratio of infected females and spread within populations.1,2 Recent successes in identifying bacterial factors responsible for reproductive parasitism3,4,5,6,7 as well as further omics approaches8,9,10,11,12 have highlighted the common appearance of deubiquitinase domains, although their biological roles-in particular, how they link to distinct manipulative phenotypes-remain poorly defined. Spiroplasma poulsonii is a helical and motile bacterial endosymbiont of Drosophila,13,14 which selectively kills male progeny with a male-killing toxin Spaid (S. poulsonii androcidin), which encodes an ovarian tumor (OTU) deubiquitinase domain.6 Artificial expression of Spaid in flies reproduces male-killing-associated pathologies that include abnormal apoptosis and neural defects during embryogenesis6,15,16,17,18,19; moreover, it highly accumulates on the dosage-compensated male X chromosome,20 congruent with cellular defects such as the DNA damage/chromatin bridge breakage specifically induced upon that chromosome.6,21,22,23 Here, I show that without the function of OTU, Spaid is polyubiquitinated and degraded through the host ubiquitin-proteasome pathway, leading to the attenuation of male-killing activity as shown previously.6 Furthermore, I find that Spaid utilizes its OTU domain to deubiquitinate itself in an intermolecular manner. Collectively, the deubiquitinase domain of Spaid serves as a self-stabilization mechanism to facilitate male killing in flies, optimizing a molecular strategy of endosymbionts that enables the efficient manipulation of the host at a low energetic cost.
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Affiliation(s)
- Toshiyuki Harumoto
- Hakubi Center for Advanced Research, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan; Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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5
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Hochstrasser M. Molecular Biology of Cytoplasmic Incompatibility Caused by Wolbachia Endosymbionts. Annu Rev Microbiol 2023; 77:299-316. [PMID: 37285552 DOI: 10.1146/annurev-micro-041020-024616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Among endosymbiotic bacteria living within eukaryotic cells, Wolbachia is exceptionally widespread, particularly in arthropods. Inherited through the female germline, it has evolved ways to increase the fraction of bacterially infected offspring by inducing parthenogenesis, feminization, male killing, or, most commonly, cytoplasmic incompatibility (CI). In CI, Wolbachia infection of males causes embryonic lethality unless they mate with similarly infected females, creating a relative reproductive advantage for infected females. A set of related Wolbachia bicistronic operons encodes the CI-inducing factors. The downstream gene encodes a deubiquitylase or nuclease and is responsible for CI induction by males, while the upstream product when expressed in females binds its sperm-introduced cognate partner and rescues viability. Both toxin-antidote and host-modification mechanisms have been proposed to explain CI. Interestingly, male killing by either Spiroplasma or Wolbachia endosymbionts involves deubiquitylases as well. Interference with the host ubiquitin system may therefore be a common theme among endosymbiont-mediated reproductive alterations.
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Affiliation(s)
- Mark Hochstrasser
- Department of Molecular Biophysics and Biochemistry and Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA;
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6
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Beckmann J, Gillespie J, Tauritz D. Modeling emergence of Wolbachia toxin-antidote protein functions with an evolutionary algorithm. Front Microbiol 2023; 14:1116766. [PMID: 37362913 PMCID: PMC10288140 DOI: 10.3389/fmicb.2023.1116766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 05/23/2023] [Indexed: 06/28/2023] Open
Abstract
Evolutionary algorithms (EAs) simulate Darwinian evolution and adeptly mimic natural evolution. Most EA applications in biology encode high levels of abstraction in top-down population ecology models. In contrast, our research merges protein alignment algorithms from bioinformatics into codon based EAs that simulate molecular protein string evolution from the bottom up. We apply our EA to reconcile a problem in the field of Wolbachia induced cytoplasmic incompatibility (CI). Wolbachia is a microbial endosymbiont that lives inside insect cells. CI is conditional insect sterility that operates as a toxin antidote (TA) system. Although, CI exhibits complex phenotypes not fully explained under a single discrete model. We instantiate in-silico genes that control CI, CI factors (cifs), as strings within the EA chromosome. We monitor the evolution of their enzymatic activity, binding, and cellular localization by applying selective pressure on their primary amino acid strings. Our model helps rationalize why two distinct mechanisms of CI induction might coexist in nature. We find that nuclear localization signals (NLS) and Type IV secretion system signals (T4SS) are of low complexity and evolve fast, whereas binding interactions have intermediate complexity, and enzymatic activity is the most complex. Our model predicts that as ancestral TA systems evolve into eukaryotic CI systems, the placement of NLS or T4SS signals can stochastically vary, imparting effects that might impact CI induction mechanics. Our model highlights how preconditions and sequence length can bias evolution of cifs toward one mechanism or another.
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Affiliation(s)
- John Beckmann
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Joe Gillespie
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Daniel Tauritz
- Department of Computer Science and Software Engineering, Auburn University, Auburn, AL, United States
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7
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Moore LD, Ballinger MJ. The toxins of vertically transmitted Spiroplasma. Front Microbiol 2023; 14:1148263. [PMID: 37275155 PMCID: PMC10232968 DOI: 10.3389/fmicb.2023.1148263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/19/2023] [Indexed: 06/07/2023] Open
Abstract
Vertically transmitted (VT) microbial symbionts play a vital role in the evolution of their insect hosts. A longstanding question in symbiont research is what genes help promote long-term stability of vertically transmitted lifestyles. Symbiont success in insect hosts is due in part to expression of beneficial or manipulative phenotypes that favor symbiont persistence in host populations. In Spiroplasma, these phenotypes have been linked to toxin and virulence domains among a few related strains. However, these domains also appear frequently in phylogenetically distant Spiroplasma, and little is known about their distribution across the Spiroplasma genus. In this study, we present the complete genome sequence of the Spiroplasma symbiont of Drosophila atripex, a non-manipulating member of the Ixodetis clade of Spiroplasma, for which genomic data are still limited. We perform a genus-wide comparative analysis of toxin domains implicated in defensive and reproductive phenotypes. From 12 VT and 31 non-VT Spiroplasma genomes, ribosome-inactivating proteins (RIPs), OTU-like cysteine proteases (OTUs), ankyrins, and ETX/MTX2 domains show high propensity for VT Spiroplasma compared to non-VT Spiroplasma. Specifically, OTU and ankyrin domains can be found only in VT-Spiroplasma, and RIP domains are found in all VT Spiroplasma and three non-VT Spiroplasma. These domains are frequently associated with Spiroplasma plasmids, suggesting a possible mechanism for dispersal and maintenance among heritable strains. Searching insect genome assemblies available on public databases uncovered uncharacterized Spiroplasma genomes from which we identified several spaid-like genes encoding RIP, OTU, and ankyrin domains, suggesting functional interactions among those domain types. Our results suggest a conserved core of symbiont domains play an important role in the evolution and persistence of VT Spiroplasma in insects.
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Affiliation(s)
- Logan D. Moore
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, United States
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8
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Beckmann J, Gillespie J, Tauritz D. Modelling Emergence of Wolbachia Toxin-Antidote Protein Functions with an Evolutionary Algorithm. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.533954. [PMID: 36993585 PMCID: PMC10055314 DOI: 10.1101/2023.03.23.533954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Evolutionary algorithms (EAs) simulate Darwinian evolution and adeptly mimic natural evolution. Most EA applications in biology encode high levels of abstraction in top-down ecological population models. In contrast, our research merges protein alignment algorithms from bioinformatics into codon based EAs that simulate molecular protein string evolution from the bottom up. We apply our EA to reconcile a problem in the field of Wolbachia induced cytoplasmic incompatibility (CI). Wolbachia is a microbial endosymbiont that lives inside insect cells. CI is conditional insect sterility that operates as a toxin antidote (TA) system. Although, CI exhibits complex phenotypes not fully explained under a single discrete model. We instantiate in-silico genes that control CI, CI factors ( cifs ), as strings within the EA chromosome. We monitor the evolution of their enzymatic activity, binding, and cellular localization by applying selective pressure on their primary amino acid strings. Our model helps rationalize why two distinct mechanisms of CI induction might coexist in nature. We find that nuclear localization signals (NLS) and Type IV secretion system signals (T4SS) are of low complexity and evolve fast, whereas binding interactions have intermediate complexity, and enzymatic activity is the most complex. Our model predicts that as ancestral TA systems evolve into eukaryotic CI systems, the placement of NLS or T4SS signals can stochastically vary, imparting effects that might impact CI induction mechanics. Our model highlights how preconditions, genetic diversity, and sequence length can bias evolution of cifs towards one mechanism or another.
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9
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Verhoeve VI, Lehman SS, Driscoll TP, Beckmann JF, Gillespie JJ. Metagenome diversity illuminates origins of pathogen effectors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.26.530123. [PMID: 36909625 PMCID: PMC10002696 DOI: 10.1101/2023.02.26.530123] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Recent metagenome assembled genome (MAG) analyses have profoundly impacted Rickettsiology systematics. Discovery of basal lineages (Mitibacteraceae and Athabascaceae) with predicted extracellular lifestyles reveals an evolutionary timepoint for the transition to host dependency, which occurred independent of mitochondrial evolution. Notably, these basal rickettsiae carry the Rickettsiales vir homolog (rvh) type IV secretion system (T4SS) and purportedly use rvh to kill congener microbes rather than parasitize host cells as described for derived rickettsial pathogens. MAG analysis also substantially increased diversity for genus Rickettsia and delineated a basal lineage (Tisiphia) that stands to inform on the rise of human pathogens from protist and invertebrate endosymbionts. Herein, we probed Rickettsiales MAG and genomic diversity for the distribution of Rickettsia rvh effectors to ascertain their origins. A sparse distribution of most Rickettsia rvh effectors outside of Rickettsiaceae lineages indicates unique rvh evolution from basal extracellular species and other rickettsial families. Remarkably, nearly every effector was found in multiple divergent forms with variable architectures, illuminating profound roles for gene duplication and recombination in shaping effector repertoires in Rickettsia pathogens. Lateral gene transfer plays a prominent role shaping the rvh effector landscape, as evinced by the discover of many effectors on plasmids and conjugative transposons, as well as pervasive effector gene exchange between Rickettsia and Legionella species. Our study exemplifies how MAGs can provide incredible insight on the origins of pathogen effectors and how their architectural modifications become tailored to eukaryotic host cell biology.
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Affiliation(s)
- Victoria I Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Stephanie S Lehman
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Timothy P Driscoll
- Department of Biology, West Virginia University, Morgantown, West Virginia, USA
| | - John F Beckmann
- Microbiology and Immunology, University of South Alabama, Mobile, AL, USA
| | - Joseph J Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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10
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Minahan NT, Wu WJ, Tsai KH. Rickettsia felis is an emerging human pathogen associated with cat fleas: A review of findings in Taiwan. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2023; 56:10-19. [PMID: 36585292 DOI: 10.1016/j.jmii.2022.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 12/03/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022]
Abstract
Rickettsia felis is an emerging rickettsial agent principally associated with cat fleas (Ctenocephalides felis), formerly discovered in 1990. Since then, clinical cases of R. felis infection have been identified globally by specific DNA sequences in patients with undifferentiated febrile illness, including in Taiwan, but such evidence is limited. R. felis rickettsiosis is self-limiting and easily treated with doxycycline, but its diagnosis remains a challenge. Environmental risk factors for R. felis rickettsiosis have yet to be clearly demonstrated, and its transmission biology is incompletely understood. Cat fleas are naturally infected with R. felis at varying rates, and vector competence in the transmission of R. felis has been demonstrated in animal models, including dogs, which may serve as reservoir hosts. In northern Taiwan, despite ∼20% of cat fleas infesting companion animals consistently found to be infected with R. felis, only a few cases of potential R. felis infection have been identified through a retrospective serological investigation, though without molecular confirmation. Ecological studies have identified divergent R. felis-like organisms in different arthropod hosts, but these strains appear to serve as nonpathogenic endosymbionts. Although its association with disease is limited, we believe cat flea-borne R. felis warrants increased recognition in an aging population due to immunosenescence and the proximity of companion animals to the elderly. Adopting a One Health approach involving collaboration and communication between clinicians, veterinarians, public health practitioners, and environmental scientists will improve our knowledge about this neglected pathogen and promote the prevention and control of vector-borne diseases.
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Affiliation(s)
- Nicholas T Minahan
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Wen-Jer Wu
- Department of Entomology, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Kun-Hsien Tsai
- Institute of Environmental and Occupational Health Sciences, College of Public Health, National Taiwan University, Taipei, Taiwan; Department of Entomology, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan; Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan.
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11
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Fan ZY, Liu Y, He ZQ, Wen Q, Chen XY, Khan MM, Osman M, Mandour NS, Qiu BL. Rickettsia Infection Benefits Its Whitefly Hosts by Manipulating Their Nutrition and Defense. INSECTS 2022; 13:1161. [PMID: 36555070 PMCID: PMC9785894 DOI: 10.3390/insects13121161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/10/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Endosymbionts play an essential role in the biology, physiology and immunity of insects. Many insects, including the whitefly Bemisia tabaci, are infected with the facultative endosymbiont Rickettsia. However, the mutualism between Rickettsia and its whitefly host remains unclear. This study investigated the biological and physiological benefits of Rickettsia infection to B. tabaci. Results revealed that infection of Rickettsia increased the fertility, the survival rate from nymph to adult and the number of female whiteflies. In addition, this facilitation caused a significant reduction in nymphal developmental duration but did not affect percentage rate of egg hatching. Rickettsia infected B. tabaci had significantly higher glycogen, soluble sugar and trehalose contents than Rickettsia negative B. tabaci individuals. Rickettsia also improved the immunity of its whitefly hosts. Rickettsia infested B. tabaci had lower mortality rates and higher semi-lethal concentrations (LC50) when exposed to the fungus Akanthomyces attenuatus and the insecticides imidacloprid and spirotetramat. The percentage of parasitism by Encarsia formosa was also reduced by Rickettsia infection. Overall, Rickettsia infection benefits B. tabaci by improving the nutritional composition of its host, and also protects B. tabaci by enhancing its resistance towards insecticides (imidacloprid and spirotetramat), entomopathogenic fungi (A. attenuatus) and its main parasitoid (E. formosa); all of which could significantly impact on current management strategies.
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Affiliation(s)
- Ze-Yun Fan
- Chongqing Key Laboratory of Vector Insects, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Engineering Research Center of Biocontrol, Ministry of Education Guangdong Province, South China Agricultural University, Guangzhou 510640, China
| | - Yuan Liu
- Chongqing Key Laboratory of Vector Insects, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Zi-Qi He
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Qin Wen
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Xin-Yi Chen
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Muhammad Musa Khan
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Mohamed Osman
- Department of Plant Protection, Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt
| | - Nasser Said Mandour
- Department of Plant Protection, Faculty of Agriculture, Suez Canal University, Ismailia 41522, Egypt
| | - Bao-Li Qiu
- Chongqing Key Laboratory of Vector Insects, College of Life Sciences, Chongqing Normal University, Chongqing 401331, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Engineering Research Center of Biocontrol, Ministry of Education Guangdong Province, South China Agricultural University, Guangzhou 510640, China
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12
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Martinez J, Ant TH, Murdochy SM, Tong L, da Silva Filipe A, Sinkins SP. Genome sequencing and comparative analysis of Wolbachia strain wAlbA reveals Wolbachia-associated plasmids are common. PLoS Genet 2022; 18:e1010406. [PMID: 36121852 PMCID: PMC9560607 DOI: 10.1371/journal.pgen.1010406] [Citation(s) in RCA: 6] [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: 07/04/2022] [Revised: 10/13/2022] [Accepted: 09/02/2022] [Indexed: 11/18/2022] Open
Abstract
Wolbachia are widespread maternally-transmitted bacteria of arthropods that often spread by manipulating their host's reproduction through cytoplasmic incompatibility (CI). Their invasive potential is currently being harnessed in field trials aiming to control mosquito-borne diseases. Wolbachia genomes commonly harbour prophage regions encoding the cif genes which confer their ability to induce CI. Recently, a plasmid-like element was discovered in wPip, a Wolbachia strain infecting Culex mosquitoes; however, it is unclear how common such extra-chromosomal elements are in Wolbachia. Here we sequenced the complete genome of wAlbA, a strain of the symbiont found in Aedes albopictus, after eliminating the co-infecting and higher density wAlbB strain that previously made sequencing of wAlbA challenging. We show that wAlbA is associated with two new plasmids and identified additional Wolbachia plasmids and related chromosomal islands in over 20% of publicly available Wolbachia genome datasets. These plasmids encode a variety of accessory genes, including several phage-like DNA packaging genes as well as genes potentially contributing to host-symbiont interactions. In particular, we recovered divergent homologues of the cif genes in both Wolbachia- and Rickettsia-associated plasmids. Our results indicate that plasmids are common in Wolbachia and raise fundamental questions around their role in symbiosis. In addition, our comparative analysis provides useful information for the future development of genetic tools to manipulate and study Wolbachia symbionts.
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Affiliation(s)
- Julien Martinez
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Thomas H. Ant
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Shivan M. Murdochy
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Lily Tong
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Ana da Silva Filipe
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Steven P. Sinkins
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
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13
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Mediannikov O, Bechah Y, Amanzougaghene N, Lepidi H, Bassene H, Sambou M, Lienhard C, Benkacimi L, Dieme C, Sokhna C, Fenollar F, Raoult D. Booklice Liposcelis bostrychophila naturally infected by Rickettsia felis cause fever and experimental pneumonia in mammals. J Infect Dis 2022; 226:1075-1083. [PMID: 35776143 DOI: 10.1093/infdis/jiac282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 06/30/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Rickettsia felis is emergent in tropical areas. Despite its high morbidity, its natural history has not yet been fully determined. We investigated the role of the common household booklouse, Liposcelis bostrychophila, recently found to harbour R. felis. METHODS Blood samples from 372 febrile patients from Senegalese villages, as well as nasal and skin samples from 264 asymptomatic individuals, were tested for cat flea-associated and booklice-associated strains of R. felis. Dust samples from beds were collected to isolate booklice and R. felis. Mice were infected with aerosol of R. felis strain from naturally infected booklice. RESULTS Forty febrile patients (11%) were infected by R. felis, including 26 (7%) by the booklice-associated strain. Nine nasal samples (3.4%) and 28 skin samples (10.6%) contained R. felis, including seven and 24, respectively, with the booklice-associated strain. The presence of live L. bostrychophila was observed in 32 dust samples (16.8%); R. felis was identified in 62 dust samples (32.5%). Several mice samples were positive for R. felis; interstitial lymphohistiocytic infiltrates were identified in lungs. CONCLUSIONS L. bostrychophila may be a reservoir of R. felis. The booklice-associated strain is pathogenic in mammals causing pneumonia. Human infection may be acquired via inhalation of infected booklice particles.
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Affiliation(s)
- Oleg Mediannikov
- Aix Marseille Univ, IRD, AP-HM, MEPHII, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Yassina Bechah
- Aix Marseille Univ, IRD, AP-HM, MEPHII, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Nadia Amanzougaghene
- Aix Marseille Univ, IRD, AP-HM, MEPHII, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Hubert Lepidi
- Aix Marseille Univ, IRD, AP-HM, MEPHII, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | | | - Masse Sambou
- VITROME, Campus International UCAD-IRD, Dakar, Senegal
| | | | - Linda Benkacimi
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
| | | | - Cheikh Sokhna
- Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
| | - Florence Fenollar
- IHU-Méditerranée Infection, Marseille, France.,Aix Marseille Univ, IRD, AP-HM, SSA, VITROME, Marseille, France
| | - Didier Raoult
- Aix Marseille Univ, IRD, AP-HM, MEPHII, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
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14
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Bordenstein SR, Bordenstein SR. Widespread phages of endosymbionts: Phage WO genomics and the proposed taxonomic classification of Symbioviridae. PLoS Genet 2022; 18:e1010227. [PMID: 35666732 PMCID: PMC9203015 DOI: 10.1371/journal.pgen.1010227] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 06/16/2022] [Accepted: 04/29/2022] [Indexed: 11/19/2022] Open
Abstract
Wolbachia are the most common obligate, intracellular bacteria in animals. They exist worldwide in arthropod and nematode hosts in which they commonly act as reproductive parasites or mutualists, respectively. Bacteriophage WO, the largest of Wolbachia’s mobile elements, includes reproductive parasitism genes, serves as a hotspot for genetic divergence and genomic rearrangement of the bacterial chromosome, and uniquely encodes a Eukaryotic Association Module with eukaryotic-like genes and an ensemble of putative host interaction genes. Despite WO’s relevance to genome evolution, selfish genetics, and symbiotic applications, relatively little is known about its origin, host range, diversification, and taxonomic classification. Here we analyze the most comprehensive set of 150 Wolbachia and phage WO assemblies to provide a framework for discretely organizing and naming integrated phage WO genomes. We demonstrate that WO is principally in arthropod Wolbachia with relatives in diverse endosymbionts and metagenomes, organized into four variants related by gene synteny, often oriented opposite the putative origin of replication in the Wolbachia chromosome, and the large serine recombinase is an ideal typing tool to distinguish the four variants. We identify a novel, putative lytic cassette and WO’s association with a conserved eleven gene island, termed Undecim Cluster, that is enriched with virulence-like genes. Finally, we evaluate WO-like Islands in the Wolbachia genome and discuss a new model in which Octomom, a notable WO-like Island, arose from a split with WO. Together, these findings establish the first comprehensive Linnaean taxonomic classification of endosymbiont phages, including non-Wolbachia phages from aquatic environments, that includes a new family and two new genera to capture the collective relatedness of these viruses.
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Affiliation(s)
- Sarah R. Bordenstein
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt Microbiome Innovation Center, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
| | - Seth R. Bordenstein
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt Microbiome Innovation Center, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Infection, Immunology, and Inflammation, Vanderbilt University, Nashville, Tennessee, United States of America
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15
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Davison HR, Pilgrim J, Wybouw N, Parker J, Pirro S, Hunter-Barnett S, Campbell PM, Blow F, Darby AC, Hurst GDD, Siozios S. Genomic diversity across the Rickettsia and 'Candidatus Megaira' genera and proposal of genus status for the Torix group. Nat Commun 2022; 13:2630. [PMID: 35551207 PMCID: PMC9098888 DOI: 10.1038/s41467-022-30385-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 04/29/2022] [Indexed: 11/09/2022] Open
Abstract
Members of the bacterial genus Rickettsia were originally identified as causative agents of vector-borne diseases in mammals. However, many Rickettsia species are arthropod symbionts and close relatives of ‘Candidatus Megaira’, which are symbiotic associates of microeukaryotes. Here, we clarify the evolutionary relationships between these organisms by assembling 26 genomes of Rickettsia species from understudied groups, including the Torix group, and two genomes of ‘Ca. Megaira’ from various insects and microeukaryotes. Our analyses of the new genomes, in comparison with previously described ones, indicate that the accessory genome diversity and broad host range of Torix Rickettsia are comparable to those of all other Rickettsia combined. Therefore, the Torix clade may play unrecognized roles in invertebrate biology and physiology. We argue this clade should be given its own genus status, for which we propose the name ‘Candidatus Tisiphia’. The bacterial genus Rickettsia includes vector-borne pathogens and arthropod symbionts that are close relatives of symbionts of microeukaryotes classified under the genus ‘Candidatus Megaira’. Here, Davison et al. clarify the evolutionary relationships between these organisms by assembling 28 genomes of understudied species, and propose that a distinct clade known as Torix Rickettsia should be considered a separate genus.
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Affiliation(s)
- Helen R Davison
- Institute of Infection, Veterinary and Ecological sciences, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Jack Pilgrim
- Institute of Infection, Veterinary and Ecological sciences, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Nicky Wybouw
- Terrestrial Ecology Unit, Department of Biology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Joseph Parker
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA, 91125, USA
| | | | - Simon Hunter-Barnett
- Institute of Infection, Veterinary and Ecological sciences, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Paul M Campbell
- Institute of Infection, Veterinary and Ecological sciences, University of Liverpool, Liverpool, L69 7ZB, UK.,School of Health and Life Sciences, Faculty of Biology Medicine and Health, the University of Manchester, Manchester, UK
| | - Frances Blow
- Institute of Infection, Veterinary and Ecological sciences, University of Liverpool, Liverpool, L69 7ZB, UK.,Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, USA
| | - Alistair C Darby
- Institute of Infection, Veterinary and Ecological sciences, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Gregory D D Hurst
- Institute of Infection, Veterinary and Ecological sciences, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Stefanos Siozios
- Institute of Infection, Veterinary and Ecological sciences, University of Liverpool, Liverpool, L69 7ZB, UK.
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16
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Verhoeve VI, Fauntleroy TD, Risteen RG, Driscoll TP, Gillespie JJ. Cryptic Genes for Interbacterial Antagonism Distinguish Rickettsia Species Infecting Blacklegged Ticks From Other Rickettsia Pathogens. Front Cell Infect Microbiol 2022; 12:880813. [PMID: 35592653 PMCID: PMC9111745 DOI: 10.3389/fcimb.2022.880813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/04/2022] [Indexed: 01/28/2023] Open
Abstract
Background The genus Rickettsia (Alphaproteobacteria: Rickettsiales) encompasses numerous obligate intracellular species with predominantly ciliate and arthropod hosts. Notable species are pathogens transmitted to mammals by blood-feeding arthropods. Mammalian pathogenicity evolved from basal, non-pathogenic host-associations; however, some non-pathogens are closely related to pathogens. One such species, Rickettsia buchneri, is prevalent in the blacklegged tick, Ixodes scapularis. While I. scapularis transmits several pathogens to humans, it does not transmit Rickettsia pathogens. We hypothesize that R. buchneri established a mutualism with I. scapularis, blocking tick superinfection with Rickettsia pathogens. Methods To improve estimates for assessing R. buchneri infection frequency in blacklegged tick populations, we used comparative genomics to identify an R. buchneri gene (REIS_1424) not present in other Rickettsia species present throughout the I. scapularis geographic range. Bioinformatic and phylogenomics approaches were employed to propose a function for the hypothetical protein (263 aa) encoded by REIS_1424. Results REIS_1424 has few analogs in other Rickettsiales genomes and greatest similarity to non-Proteobacteria proteins. This cohort of proteins varies greatly in size and domain composition, possessing characteristics of Recombination hotspot (Rhs) and contact dependent growth inhibition (CDI) toxins, with similarity limited to proximal C-termini (~145 aa). This domain was named CDI-like/Rhs-like C-terminal toxin (CRCT). As such proteins are often found as toxin-antidote (TA) modules, we interrogated REIS_1423 (151 aa) as a putative antidote. Indeed, REIS_1423 is similar to proteins encoded upstream of CRCT domain-containing proteins. Accordingly, we named these proteins CDI-like/Rhs-like C-terminal toxin antidotes (CRCA). R. buchneri expressed both REIS_1423 and REIS_1424 in tick cell culture, and PCR assays showed specificity for R. buchneri over other rickettsiae and utility for positive detection in three tick populations. Finally, phylogenomics analyses uncovered divergent CRCT/CRCA modules in varying states of conservation; however, only R. buchneri and related Tamurae/Ixodes Group rickettsiae carry complete TA modules. Conclusion We hypothesize that Rickettsia CRCT/CRCA modules circulate in the Rickettsia mobile gene pool, arming rickettsiae for battle over arthropod colonization. While its functional significance remains to be tested, R. buchneri CRCT/CRCA serves as a marker to positively identify infection and begin deciphering the role this endosymbiont plays in the biology of the blacklegged tick.
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Affiliation(s)
- Victoria I. Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Tyesha D. Fauntleroy
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Riley G. Risteen
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Timothy P. Driscoll
- Department of Biology, West Virginia University, Morgantown, WV, United States
| | - Joseph J. Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
- *Correspondence: Joseph J. Gillespie,
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17
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Quek S, Cerdeira L, Jeffries CL, Tomlinson S, Walker T, Hughes GL, Heinz E. Wolbachia endosymbionts in two Anopheles species indicates independent acquisitions and lack of prophage elements. Microb Genom 2022; 8. [PMID: 35446252 PMCID: PMC9453072 DOI: 10.1099/mgen.0.000805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Wolbachia is a genus of obligate bacterial endosymbionts that infect a diverse range of arthropod species as well as filarial nematodes, with its single described species, Wolbachia pipientis, divided into several ‘supergroups’ based on multilocus sequence typing. Wolbachia strains in mosquitoes have been shown to inhibit the transmission of human pathogens, including Plasmodium malaria parasites and arboviruses. Despite their large host range, Wolbachia strains within the major malaria vectors of the Anopheles gambiae and Anopheles funestus complexes appear at low density, established solely on PCR-based methods. Questions have been raised as to whether this represents a true endosymbiotic relationship. However, recent definitive evidence for two distinct, high-density strains of supergroup B Wolbachia within Anopheles demeilloni and Anopheles moucheti has opened exciting possibilities to explore naturally occurring Wolbachia endosymbionts in Anopheles for biocontrol strategies to block Plasmodium transmission. Here, we utilize genomic analyses to demonstrate that both Wolbachia strains have retained all key metabolic and transport pathways despite their smaller genome size, with this reduction potentially attributable to degenerated prophage regions. Even with this reduction, we confirmed the presence of cytoplasmic incompatibility (CI) factor genes within both strains, with wAnD maintaining intact copies of these genes while the cifB gene was interrupted in wAnM, so functional analysis is required to determine whether wAnM can induce CI. Additionally, phylogenetic analysis indicates that these Wolbachia strains may have been introduced into these two Anopheles species via horizontal transmission events, rather than by ancestral acquisition and subsequent loss events in the Anopheles gambiae species complex. These are the first Wolbachia genomes, to our knowledge, that enable us to study the relationship between natural strain Plasmodium malaria parasites and their anopheline hosts.
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Affiliation(s)
- Shannon Quek
- Department of Tropical Disease Biology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Louise Cerdeira
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Claire L Jeffries
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Sean Tomlinson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Thomas Walker
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Grant L Hughes
- Department of Tropical Disease Biology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK.,Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Eva Heinz
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.,Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
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18
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The CinB Nuclease from wNo Wolbachia Is Sufficient for Induction of Cytoplasmic Incompatibility in Drosophila. mBio 2022; 13:e0317721. [PMID: 35073749 PMCID: PMC8787490 DOI: 10.1128/mbio.03177-21] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Wolbachia is an obligate intracellular bacterium that can alter reproduction of its arthropod hosts, often through a mechanism called cytoplasmic incompatibility (CI). In CI, uninfected females fertilized by infected males yield few offspring, but if both are similarly infected, normal embryo viability results (called "rescue"). CI factors (Cifs) responsible for CI are pairs of proteins encoded by linked genes. The downstream gene in each pair encodes either a deubiquitylase (CidB) or a nuclease (CinB). The upstream gene products, CidA and CinA, bind their cognate enzymes with high specificity. Expression of CidB or CinB in yeast inhibits growth, but growth is rescued by expression of the cognate CifA protein. By contrast, transgenic Drosophila male germ line expression of both cifA and cifB was reported to be necessary to induce CI-like embryonic arrest; cifA expression alone in females is sufficient for rescue. This pattern, seen with genes from several Wolbachia strains, has been called the "2-by-1" model. Here, we show that male germ line expression of the cinB gene alone, from a distinct clade of cif genes from wNo Wolbachia, is sufficient to induce nearly complete loss of embryo viability. This male sterility is fully rescued by cognate cinAwNo expression in the female germ line. The proteins behave similarly in yeast. CinBwNo toxicity depends on its nuclease active site. These results demonstrate that highly divergent CinB nucleases can induce CI, that rescue by cognate CifA factors is a general feature of Wolbachia CI systems, and that CifA is not strictly required in males for CI induction. IMPORTANCE Wolbachia bacteria live within the cells of many insects. Like mitochondria, they are only inherited from females. Wolbachia often increases the number of infected females to promote spread of infection using a type of male sterility called cytoplasmic incompatibility (CI): when uninfected females mate with infected males, most embryos die; if both are similarly infected, embryos develop normally, giving infected females an advantage in producing offspring. CI is being used against disease-carrying mosquitoes and agricultural pests. Wolbachia proteins called CifA and CifB, which bind one another, cause CI, but how they work has been unclear. Here, we show that a CifB protein singly produced in fruit fly males causes sterility in crosses to normal females, but this is rescued if the females produce the CifA partner. These findings clarify a broad range of observations on CI and will allow more rational approaches to using it for insect control.
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19
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Massey JH, Newton ILG. Diversity and function of arthropod endosymbiont toxins. Trends Microbiol 2022; 30:185-198. [PMID: 34253453 PMCID: PMC8742837 DOI: 10.1016/j.tim.2021.06.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 02/03/2023]
Abstract
Bacterial endosymbionts induce dramatic phenotypes in their arthropod hosts, including cytoplasmic incompatibility, feminization, parthenogenesis, male killing, parasitoid defense, and pathogen blocking. The molecular mechanisms underlying these effects remain largely unknown but recent evidence suggests that protein toxins secreted by the endosymbionts play a role. Here, we describe the diversity and function of endosymbiont proteins with homology to known bacterial toxins. We focus on maternally transmitted endosymbionts belonging to the Wolbachia, Rickettsia, Arsenophonus, Hamiltonella, Spiroplasma, and Cardinium genera because of their ability to induce the above phenotypes. We identify at least 16 distinct toxin families with diverse enzymatic activities, including AMPylases, nucleases, proteases, and glycosyltransferases. Notably, several annotated toxins contain domains with homology to eukaryotic proteins, suggesting that arthropod endosymbionts mimic host biochemistry to manipulate host physiology, similar to bacterial pathogens.
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Affiliation(s)
| | - Irene L. G. Newton
- Department of Biology, Indiana University, Bloomington, Indiana, USA,Corresponding author,
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20
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Structural and mechanistic insights into the complexes formed by Wolbachia cytoplasmic incompatibility factors. Proc Natl Acad Sci U S A 2021; 118:2107699118. [PMID: 34620712 DOI: 10.1073/pnas.2107699118] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2021] [Indexed: 11/18/2022] Open
Abstract
Wolbachia bacteria, inherited through the female germ line, infect a large fraction of arthropod species. Many Wolbachia strains manipulate host reproduction, most commonly through cytoplasmic incompatibility (CI). CI, a conditional male sterility, results when Wolbachia-infected male insects mate with uninfected females; viability is restored if the female is similarly infected (called "rescue"). CI is used to help control mosquito-borne viruses such as dengue and Zika, but its mechanisms remain unknown. The coexpressed CI factors CifA and CifB form stable complexes in vitro, but the timing and function of this interaction in the insect are unresolved. CifA expression in the female germ line is sufficient for rescue. We report high-resolution structures of a CI-factor complex, CinA-CinB, which utilizes a unique binding mode between the CinA rescue factor and the CinB nuclease; the structures were validated by biochemical and yeast growth analyses. Importantly, transgenic expression in Drosophila of a nonbinding CinA mutant, designed based on the CinA-CinB structure, suggests CinA expressed in females must bind CinB imported by sperm in order to rescue embryonic viability. Binding between cognate factors is conserved in an enzymatically distinct CI system, CidA-CidB, suggesting universal features in Wolbachia CI induction and rescue.
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21
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Beckmann JF, Van Vaerenberghe K, Akwa DE, Cooper BS. A single mutation weakens symbiont-induced reproductive manipulation through reductions in deubiquitylation efficiency. Proc Natl Acad Sci U S A 2021; 118:e2113271118. [PMID: 34548405 PMCID: PMC8488622 DOI: 10.1073/pnas.2113271118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2021] [Indexed: 11/18/2022] Open
Abstract
Animals interact with microbes that affect their performance and fitness, including endosymbionts that reside inside their cells. Maternally transmitted Wolbachia bacteria are the most common known endosymbionts, in large part because of their manipulation of host reproduction. For example, many Wolbachia cause cytoplasmic incompatibility (CI) that reduces host embryonic viability when Wolbachia-modified sperm fertilize uninfected eggs. Operons termed cifs control CI, and a single factor (cifA) rescues it, providing Wolbachia-infected females a fitness advantage. Despite CI's prevalence in nature, theory indicates that natural selection does not act to maintain CI, which varies widely in strength. Here, we investigate the genetic and functional basis of CI-strength variation observed among sister Wolbachia that infect Drosophila melanogaster subgroup hosts. We cloned, Sanger sequenced, and expressed cif repertoires from weak CI-causing wYak in Drosophila yakuba, revealing mutations suspected to weaken CI relative to model wMel in D. melanogaster A single valine-to-leucine mutation within the deubiquitylating (DUB) domain of the wYak cifB homolog (cidB) ablates a CI-like phenotype in yeast. The same mutation reduces both DUB efficiency in vitro and transgenic CI strength in the fly, each by about twofold. Our results map hypomorphic transgenic CI to reduced DUB activity and indicate that deubiquitylation is central to CI induction in cid systems. We also characterize effects of other genetic variation distinguishing wMel-like cifs Importantly, CI strength determines Wolbachia prevalence in natural systems and directly influences the efficacy of Wolbachia biocontrol strategies in transinfected mosquito systems. These approaches rely on strong CI to reduce human disease.
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Affiliation(s)
- John F Beckmann
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849;
| | | | - Daniel E Akwa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849
| | - Brandon S Cooper
- Division of Biological Sciences, University of Montana, Missoula, MT 59801
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22
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Shropshire JD, Rosenberg R, Bordenstein SR. The impacts of cytoplasmic incompatibility factor (cifA and cifB) genetic variation on phenotypes. Genetics 2021; 217:1-13. [PMID: 33683351 PMCID: PMC8218869 DOI: 10.1093/genetics/iyaa007] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/13/2020] [Indexed: 11/13/2022] Open
Abstract
Wolbachia are maternally transmitted, intracellular bacteria that can
often selfishly spread through arthropod populations via cytoplasmic incompatibility (CI).
CI manifests as embryonic death when males expressing prophage WO genes
cifA and cifB mate with uninfected females or females
harboring an incompatible Wolbachia strain. Females with a compatible
cifA-expressing strain rescue CI. Thus, cif-mediated
CI confers a relative fitness advantage to females transmitting
Wolbachia. However, whether cif sequence variation
underpins incompatibilities between Wolbachia strains and variation in CI
penetrance remains unknown. Here, we engineer Drosophila melanogaster to
transgenically express cognate and non-cognate cif homologs and assess
their CI and rescue capability. Cognate expression revealed that cifA;B
native to D. melanogaster causes strong CI, and cognate
cifA;B homologs from two other Drosophila-associated
Wolbachia cause weak transgenic CI, including the first demonstration
of phylogenetic type 2 cifA;B CI. Intriguingly, non-cognate expression of
cifA and cifB alleles from different strains revealed
that cifA homologs generally contribute to strong transgenic CI and
interchangeable rescue despite their evolutionary divergence, and cifB
genetic divergence contributes to weak or no transgenic CI. Finally, we find that a type 1
cifA can rescue CI caused by a genetically divergent type 2
cifA;B in a manner consistent with unidirectional incompatibility. By
genetically dissecting individual CI functions for type 1 and 2 cifA and
cifB, this work illuminates new relationships between
cif genotype and CI phenotype. We discuss the relevance of these
findings to CI’s genetic basis, phenotypic variation patterns, and mechanism.
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Affiliation(s)
- J Dylan Shropshire
- Department of Biological Sciences, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235, USA.,Vanderbilt Microbiome Initiative, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235, USA.,Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
| | - Rachel Rosenberg
- Department of Biological Sciences, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235, USA.,Vanderbilt Microbiome Initiative, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235, USA
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235, USA.,Vanderbilt Microbiome Initiative, Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235, USA.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN 37235, USA
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23
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Caragata EP, Dutra HLC, Sucupira PHF, Ferreira AGA, Moreira LA. Wolbachia as translational science: controlling mosquito-borne pathogens. Trends Parasitol 2021; 37:1050-1067. [PMID: 34303627 DOI: 10.1016/j.pt.2021.06.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/21/2021] [Accepted: 06/29/2021] [Indexed: 01/23/2023]
Abstract
In this review we examine how exploiting the Wolbachia-mosquito relationship has become an increasingly popular strategy for controlling arbovirus transmission. Field deployments of Wolbachia-infected mosquitoes have led to significant decreases in dengue virus incidence via high levels of mosquito population suppression and replacement, emphasizing the success of Wolbachia approaches. Here, we examine how improved knowledge of Wolbachia-host interactions has provided key insight into the mechanisms of the essential phenotypes of pathogen blocking and cytoplasmic incompatibility. And we discuss recent studies demonstrating that extrinsic factors, such as ambient temperature, can modulate Wolbachia density and maternal transmission. Finally, we assess the prospects of using Wolbachia to control other vectors and agricultural pest species.
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Affiliation(s)
- Eric P Caragata
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, USA.
| | - Heverton L C Dutra
- Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Pedro H F Sucupira
- Mosquitos Vetores: Endossimbiontes e Interação Patógeno-Vetor, Instituto René Rachou - Fiocruz, Belo Horizonte, MG, Brazil
| | - Alvaro G A Ferreira
- Mosquitos Vetores: Endossimbiontes e Interação Patógeno-Vetor, Instituto René Rachou - Fiocruz, Belo Horizonte, MG, Brazil
| | - Luciano A Moreira
- Mosquitos Vetores: Endossimbiontes e Interação Patógeno-Vetor, Instituto René Rachou - Fiocruz, Belo Horizonte, MG, Brazil.
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24
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Salje J. Cells within cells: Rickettsiales and the obligate intracellular bacterial lifestyle. Nat Rev Microbiol 2021; 19:375-390. [PMID: 33564174 DOI: 10.1038/s41579-020-00507-2] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2020] [Indexed: 01/01/2023]
Abstract
The Rickettsiales are a group of obligate intracellular vector-borne Gram-negative bacteria that include many organisms of clinical and agricultural importance, including Anaplasma spp., Ehrlichia chaffeensis, Wolbachia, Rickettsia spp. and Orientia tsutsugamushi. This Review provides an overview of the current state of knowledge of the biology of these bacteria and their interactions with host cells, with a focus on pathogenic species or those that are otherwise important for human health. This includes a description of rickettsial genomics, bacterial cell biology, the intracellular lifestyles of Rickettsiales and the mechanisms by which they induce and evade the innate immune response.
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Affiliation(s)
- Jeanne Salje
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK. .,Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Public Health Research Institute, Rutgers University, Newark, NJ, USA.
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25
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Martinez J, Klasson L, Welch JJ, Jiggins FM. Life and Death of Selfish Genes: Comparative Genomics Reveals the Dynamic Evolution of Cytoplasmic Incompatibility. Mol Biol Evol 2021; 38:2-15. [PMID: 32797213 PMCID: PMC7783169 DOI: 10.1093/molbev/msaa209] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cytoplasmic incompatibility is a selfish reproductive manipulation induced by the endosymbiont Wolbachia in arthropods. In males Wolbachia modifies sperm, leading to embryonic mortality in crosses with Wolbachia-free females. In females, Wolbachia rescues the cross and allows development to proceed normally. This provides a reproductive advantage to infected females, allowing the maternally transmitted symbiont to spread rapidly through host populations. We identified homologs of the genes underlying this phenotype, cifA and cifB, in 52 of 71 new and published Wolbachia genome sequences. They are strongly associated with cytoplasmic incompatibility. There are up to seven copies of the genes in each genome, and phylogenetic analysis shows that Wolbachia frequently acquires new copies due to pervasive horizontal transfer between strains. In many cases, the genes have subsequently acquired loss-of-function mutations to become pseudogenes. As predicted by theory, this tends to occur first in cifB, whose sole function is to modify sperm, and then in cifA, which is required to rescue the cross in females. Although cif genes recombine, recombination is largely restricted to closely related homologs. This is predicted under a model of coevolution between sperm modification and embryonic rescue, where recombination between distantly related pairs of genes would create a self-incompatible strain. Together, these patterns of gene gain, loss, and recombination support evolutionary models of cytoplasmic incompatibility.
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Affiliation(s)
- Julien Martinez
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow, United Kingdom
| | - Lisa Klasson
- Molecular Evolution, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - John J Welch
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Francis M Jiggins
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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26
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Driscoll TP, Verhoeve VI, Brockway C, Shrewsberry DL, Plumer M, Sevdalis SE, Beckmann JF, Krueger LM, Macaluso KR, Azad AF, Gillespie JJ. Evolution of Wolbachia mutualism and reproductive parasitism: insight from two novel strains that co-infect cat fleas. PeerJ 2020; 8:e10646. [PMID: 33362982 PMCID: PMC7750005 DOI: 10.7717/peerj.10646] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/03/2020] [Indexed: 12/26/2022] Open
Abstract
Wolbachiae are obligate intracellular bacteria that infect arthropods and certain nematodes. Usually maternally inherited, they may provision nutrients to (mutualism) or alter sexual biology of (reproductive parasitism) their invertebrate hosts. We report the assembly of closed genomes for two novel wolbachiae, wCfeT and wCfeJ, found co-infecting cat fleas (Ctenocephalides felis) of the Elward Laboratory colony (Soquel, CA, USA). wCfeT is basal to nearly all described Wolbachia supergroups, while wCfeJ is related to supergroups C, D and F. Both genomes contain laterally transferred genes that inform on the evolution of Wolbachia host associations. wCfeT carries the Biotin synthesis Operon of Obligate intracellular Microbes (BOOM); our analyses reveal five independent acquisitions of BOOM across the Wolbachia tree, indicating parallel evolution towards mutualism. Alternately, wCfeJ harbors a toxin-antidote operon analogous to the wPip cinAB operon recently characterized as an inducer of cytoplasmic incompatibility (CI) in flies. wCfeJ cinB and three adjacent genes are collectively similar to large modular toxins encoded in CI-like operons of certain Wolbachia strains and Rickettsia species, signifying that CI toxins streamline by fission of large modular toxins. Remarkably, the C. felis genome itself contains two CI-like antidote genes, divergent from wCfeJ cinA, revealing episodic reproductive parasitism in cat fleas and evidencing mobility of CI loci independent of WO-phage. Additional screening revealed predominant co-infection (wCfeT/wCfeJ) amongst C. felis colonies, though fleas in wild populations mostly harbor wCfeT alone. Collectively, genomes of wCfeT, wCfeJ, and their cat flea host supply instances of lateral gene transfers that could drive transitions between parasitism and mutualism.
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Affiliation(s)
| | - Victoria I Verhoeve
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| | | | | | - Mariah Plumer
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| | - Spiridon E Sevdalis
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| | - John F Beckmann
- Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Laura M Krueger
- Orange County Mosquito and Vector Control District, Garden Grove, CA, USA
| | - Kevin R Macaluso
- Microbiology and Immunology, University of South Alabama, Mobile, AL, USA
| | - Abdu F Azad
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
| | - Joseph J Gillespie
- Microbiology and Immunology, University of Maryland at Baltimore, Baltimore, MD, USA
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27
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Semiatizki A, Weiss B, Bagim S, Rohkin-Shalom S, Kaltenpoth M, Chiel E. Effects, interactions, and localization of Rickettsia and Wolbachia in the house fly parasitoid, Spalangia endius. MICROBIAL ECOLOGY 2020; 80:718-728. [PMID: 32488484 DOI: 10.1007/s00248-020-01520-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/28/2020] [Indexed: 06/11/2023]
Abstract
Many insect species harbor facultative microbial symbionts that affect their biology in diverse ways. Here, we studied the effects, interactions, and localization of two bacterial symbionts-Wolbachia and Rickettsia-in the parasitoid Spalangia endius. We crossed between four S. endius colonies-Wolbachia only (W), Rickettsia only (R), both (WR), and none (aposymbiotic, APS) (16 possible crosses) and found that Wolbachia induces incomplete cytoplasmic incompatibility (CI), both when the males are W or WR. Rickettsia did not cause reproductive manipulations and did not rescue the Wolbachia-induced CI. However, when R females were crossed with W or WR males, significantly less offspring were produced compared with that of control crosses. In non-CI crosses, the presence of Wolbachia in males caused a significant reduction in offspring numbers. Females' developmental time was significantly prolonged in the R colony, with adults starting to emerge one day later than the other colonies. Other fitness parameters did not differ significantly between the colonies. Using fluorescence in situ hybridization microscopy in females, we found that Wolbachia is localized alongside Rickettsia inside oocytes, follicle cells, and nurse cells in the ovaries. However, Rickettsia is distributed also in muscle cells all over the body, in ganglia, and even in the brain.
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Affiliation(s)
- Amit Semiatizki
- Department of Biology and Environment, University of Haifa-Oranim, 36006, Tivon, Israel
| | - Benjamin Weiss
- Department for Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
| | - Shir Bagim
- Department of Biology and Environment, University of Haifa-Oranim, 36006, Tivon, Israel
| | - Sarit Rohkin-Shalom
- Department of Biology and Environment, University of Haifa-Oranim, 36006, Tivon, Israel
| | - Martin Kaltenpoth
- Department for Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
| | - Elad Chiel
- Department of Biology and Environment, University of Haifa-Oranim, 36006, Tivon, Israel.
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28
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Shropshire JD, Leigh B, Bordenstein SR. Symbiont-mediated cytoplasmic incompatibility: what have we learned in 50 years? eLife 2020; 9:61989. [PMID: 32975515 PMCID: PMC7518888 DOI: 10.7554/elife.61989] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 09/14/2020] [Indexed: 12/12/2022] Open
Abstract
Cytoplasmic incompatibility (CI) is the most common symbiont-induced reproductive manipulation. Specifically, symbiont-induced sperm modifications cause catastrophic mitotic defects in the fertilized embryo and ensuing lethality in crosses between symbiotic males and either aposymbiotic females or females harboring a different symbiont strain. However, if the female carries the same symbiont strain, then embryos develop properly, thereby imparting a relative fitness benefit to symbiont-transmitting mothers. Thus, CI drives maternally-transmitted bacteria to high frequencies in arthropods worldwide. In the past two decades, CI experienced a boom in interest due to its (i) deployment in worldwide efforts to curb mosquito-borne diseases, (ii) causation by bacteriophage genes, cifA and cifB, that modify sexual reproduction, and (iii) important impacts on arthropod speciation. This review serves as a gateway to experimental, conceptual, and quantitative themes of CI and outlines significant gaps in understanding CI’s mechanism that are ripe for investigation from diverse subdisciplines in the life sciences.
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Affiliation(s)
- J Dylan Shropshire
- Department of Biological Sciences, Vanderbilt University, Nashville, United States.,Vanderbilt Microbiome Initiative, Vanderbilt University, Nashville, United States
| | - Brittany Leigh
- Department of Biological Sciences, Vanderbilt University, Nashville, United States.,Vanderbilt Microbiome Initiative, Vanderbilt University, Nashville, United States
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University, Nashville, United States.,Vanderbilt Microbiome Initiative, Vanderbilt University, Nashville, United States.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, United States.,Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, United States
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29
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Chen H, Zhang M, Hochstrasser M. The Biochemistry of Cytoplasmic Incompatibility Caused by Endosymbiotic Bacteria. Genes (Basel) 2020; 11:genes11080852. [PMID: 32722516 PMCID: PMC7465683 DOI: 10.3390/genes11080852] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/19/2020] [Accepted: 07/20/2020] [Indexed: 12/29/2022] Open
Abstract
Many species of arthropods carry maternally inherited bacterial endosymbionts that can influence host sexual reproduction to benefit the bacterium. The most well-known of such reproductive parasites is Wolbachia pipientis. Wolbachia are obligate intracellular α-proteobacteria found in nearly half of all arthropod species. This success has been attributed in part to their ability to manipulate host reproduction to favor infected females. Cytoplasmic incompatibility (CI), a phenomenon wherein Wolbachia infection renders males sterile when they mate with uninfected females, but not infected females (the rescue mating), appears to be the most common. CI provides a reproductive advantage to infected females in the presence of a threshold level of infected males. The molecular mechanisms of CI and other reproductive manipulations, such as male killing, parthenogenesis, and feminization, have remained mysterious for many decades. It had been proposed by Werren more than two decades ago that CI is caused by a Wolbachia-mediated sperm modification and that rescue is achieved by a Wolbachia-encoded rescue factor in the infected egg. In the past few years, new research has highlighted a set of syntenic Wolbachia gene pairs encoding CI-inducing factors (Cifs) as the key players for the induction of CI and its rescue. Within each Cif pair, the protein encoded by the upstream gene is denoted A and the downstream gene B. To date, two types of Cifs have been characterized based on the enzymatic activity identified in the B protein of each protein pair; one type encodes a deubiquitylase (thus named CI-inducing deubiquitylase or cid), and a second type encodes a nuclease (named CI-inducing nuclease or cin). The CidA and CinA proteins bind tightly and specifically to their respective CidB and CinB partners. In transgenic Drosophila melanogaster, the expression of either the Cid or Cin protein pair in the male germline induces CI and the expression of the cognate A protein in females is sufficient for rescue. With the identity of the Wolbachia CI induction and rescue factors now known, research in the field has turned to directed studies on the molecular mechanisms of CI, which we review here.
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Affiliation(s)
- Hongli Chen
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06511, USA; (H.C.); (M.Z.)
| | - Mengwen Zhang
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06511, USA; (H.C.); (M.Z.)
- Department of Chemistry, Yale University, New Haven, CT 06511, USA
| | - Mark Hochstrasser
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06511, USA; (H.C.); (M.Z.)
- Department of Molecular, Cellular, & Developmental Biology, Yale University, New Haven, CT 06511, USA
- Correspondence:
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30
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Rosenwald LC, Sitvarin MI, White JA. Endosymbiotic Rickettsiella causes cytoplasmic incompatibility in a spider host. Proc Biol Sci 2020; 287:20201107. [PMID: 32635864 DOI: 10.1098/rspb.2020.1107] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Many arthropod hosts are infected with bacterial endosymbionts that manipulate host reproduction, but few bacterial taxa have been shown to cause such manipulations. Here, we show that a bacterial strain in the genus Rickettsiella causes cytoplasmic incompatibility (CI) between infected and uninfected hosts. We first surveyed the bacterial community of the agricultural spider Mermessus fradeorum (Linyphiidae) using high throughput sequencing and found that individual spiders can be infected with up to five different strains of maternally inherited symbiont from the genera Wolbachia, Rickettsia, and Rickettsiella. The Rickettsiella strain was pervasive, found in all 23 tested spider matrilines. We used antibiotic curing to generate uninfected matrilines that we reciprocally crossed with individuals infected only with Rickettsiella. We found that only 13% of eggs hatched when uninfected females were mated with Rickettsiella-infected males; in contrast, at least 83% of eggs hatched in the other cross types. This is the first documentation of Rickettsiella, or any Gammaproteobacteria, causing CI. We speculate that induction of CI may be much more widespread among maternally inherited bacteria than previously appreciated. Further, our results reinforce the importance of thoroughly characterizing and assessing the inherited microbiome before attributing observed host phenotypes to well-characterized symbionts such as Wolbachia.
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Affiliation(s)
- Laura C Rosenwald
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center N, Lexington, KY, USA
| | - Michael I Sitvarin
- Department of Biology, Clayton State University, 2000 Clayton State Blvd., Morrow, GA, USA
| | - Jennifer A White
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center N, Lexington, KY, USA
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31
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Driscoll TP, Verhoeve VI, Gillespie JJ, Johnston JS, Guillotte ML, Rennoll-Bankert KE, Rahman MS, Hagen D, Elsik CG, Macaluso KR, Azad AF. A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity. BMC Biol 2020; 18:70. [PMID: 32560686 PMCID: PMC7305587 DOI: 10.1186/s12915-020-00802-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 05/29/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Fleas (Insecta: Siphonaptera) are small flightless parasites of birds and mammals; their blood-feeding can transmit many serious pathogens (i.e., the etiological agents of bubonic plague, endemic and murine typhus). The lack of flea genome assemblies has hindered research, especially comparisons to other disease vectors. Accordingly, we sequenced the genome of the cat flea, Ctenocephalides felis, an insect with substantial human health and veterinary importance across the globe. RESULTS By combining Illumina and PacBio sequencing of DNA derived from multiple inbred female fleas with Hi-C scaffolding techniques, we generated a chromosome-level genome assembly for C. felis. Unexpectedly, our assembly revealed extensive gene duplication across the entire genome, exemplified by ~ 38% of protein-coding genes with two or more copies and over 4000 tRNA genes. A broad range of genome size determinations (433-551 Mb) for individual fleas sampled across different populations supports the widespread presence of fluctuating copy number variation (CNV) in C. felis. Similarly, broad genome sizes were also calculated for individuals of Xenopsylla cheopis (Oriental rat flea), indicating that this remarkable "genome-in-flux" phenomenon could be a siphonapteran-wide trait. Finally, from the C. felis sequence reads, we also generated closed genomes for two novel strains of Wolbachia, one parasitic and one symbiotic, found to co-infect individual fleas. CONCLUSION Rampant CNV in C. felis has dire implications for gene-targeting pest control measures and stands to complicate standard normalization procedures utilized in comparative transcriptomics analysis. Coupled with co-infection by novel Wolbachia endosymbionts-potential tools for blocking pathogen transmission-these oddities highlight a unique and underappreciated disease vector.
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Affiliation(s)
| | - Victoria I Verhoeve
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joseph J Gillespie
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - J Spencer Johnston
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Mark L Guillotte
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kristen E Rennoll-Bankert
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - M Sayeedur Rahman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Darren Hagen
- Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK, USA
| | - Christine G Elsik
- Division of Animal Sciences, University of Missouri, Columbia, MO, USA
- Division of Plant Sciences, University of Missouri, Columbia, MO, USA
- MU Informatics Institute, University of Missouri, Columbia, MO, USA
| | - Kevin R Macaluso
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL, USA
| | - Abdu F Azad
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
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32
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Computational evidence for antitoxins associated with RelE/ParE, RatA, Fic, and AbiEii-family toxins in Wolbachia genomes. Mol Genet Genomics 2020; 295:891-909. [DOI: 10.1007/s00438-020-01662-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023]
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33
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Beckmann JF, Sharma GD, Mendez L, Chen H, Hochstrasser M. The Wolbachia cytoplasmic incompatibility enzyme CidB targets nuclear import and protamine-histone exchange factors. eLife 2019; 8:e50026. [PMID: 31774393 PMCID: PMC6881146 DOI: 10.7554/elife.50026] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/13/2019] [Indexed: 01/22/2023] Open
Abstract
Intracellular Wolbachia bacteria manipulate arthropod reproduction to promote their own inheritance. The most prevalent mechanism, cytoplasmic incompatibility (CI), traces to a Wolbachia deubiquitylase, CidB, and CidA. CidB has properties of a toxin, while CidA binds CidB and rescues embryonic viability. CidB is also toxic to yeast where we identified both host effects and high-copy suppressors of toxicity. The strongest suppressor was karyopherin-α, a nuclear-import receptor; this required nuclear localization-signal binding. A protein-interaction screen of Drosophila extracts using a substrate-trapping catalytic mutant, CidB*, also identified karyopherin-α; the P32 protamine-histone exchange factor bound as well. When CidB* bound CidA, these host protein interactions disappeared. These associations would place CidB at the zygotic male pronucleus where CI defects first manifest. Overexpression of karyopherin-α, P32, or CidA in female flies suppressed CI. We propose that CidB targets nuclear-protein import and protamine-histone exchange and that CidA rescues embryos by restricting CidB access to its targets.
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Affiliation(s)
| | - Gagan Deep Sharma
- Department of Entomology and Plant PathologyAuburn UniversityAuburnUnited States
| | - Luis Mendez
- Department of Entomology and Plant PathologyAuburn UniversityAuburnUnited States
| | - Hongli Chen
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenUnited States
| | - Mark Hochstrasser
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenUnited States
- Department of Molecular, Cellular, and Developmental BiologyYale UniversityNew HavenUnited States
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34
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Chen H, Ronau JA, Beckmann JF, Hochstrasser M. A Wolbachia nuclease and its binding partner provide a distinct mechanism for cytoplasmic incompatibility. Proc Natl Acad Sci U S A 2019; 116:22314-22321. [PMID: 31615889 PMCID: PMC6825299 DOI: 10.1073/pnas.1914571116] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wolbachia are endosymbiotic bacteria that infect nearly half of all arthropod species. This pandemic is due in part to their ability to increase their transmission through the female germline, most commonly by a mechanism called cytoplasmic incompatibility (CI). The Wolbachia cid operon, encoding 2 proteins, CidA and CidB, the latter a deubiquitylating enzyme (DUB), recapitulates CI in transgenic Drosophila melanogaster However, some CI-inducing Wolbachia strains lack a DUB-encoding cid operon; it was therefore proposed that the related cin operon codes for an alternative CI system. Here we show that the Wolbachia cin operon encodes a nuclease, CinB, and a second protein, CinA, that tightly binds CinB. Recombinant CinB has nuclease activity against both single-stranded and double-stranded DNA but not RNA under the conditions tested. Expression of the cin operon in transgenic male flies induces male sterility and embryonic defects typical of CI. Importantly, transgenic CinA can rescue defects in egg-hatch rates when expressed in females. Expression of CinA also rescues CinB-induced growth defects in yeast. CinB has 2 PD-(D/E)xK nuclease domains, and both are required for nuclease activity and for toxicity in yeast and flies. Our data suggest a distinct mechanism for CI involving a nuclease toxin and highlight the central role of toxin-antidote operons in Wolbachia-induced cytoplasmic incompatibility.
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Affiliation(s)
- Hongli Chen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
| | - Judith A Ronau
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
| | - John F Beckmann
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 26849
| | - Mark Hochstrasser
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511;
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511
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35
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Siozios S, Pilgrim J, Darby AC, Baylis M, Hurst GDD. The draft genome of strain cCpun from biting midges confirms insect Cardinium are not a monophyletic group and reveals a novel gene family expansion in a symbiont. PeerJ 2019; 7:e6448. [PMID: 30809447 PMCID: PMC6387759 DOI: 10.7717/peerj.6448] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/15/2019] [Indexed: 01/02/2023] Open
Abstract
Background It is estimated that 13% of arthropod species carry the heritable symbiont Cardinium hertigii. 16S rRNA and gyrB sequence divides this species into at least four groups (A–D), with the A group infecting a range of arthropods, the B group infecting nematode worms, the C group infecting Culicoides biting midges, and the D group associated with the marine copepod Nitocra spinipes. To date, genome sequence has only been available for strains from groups A and B, impeding general understanding of the evolutionary history of the radiation. We present a draft genome sequence for a C group Cardinium, motivated both by the paucity of genomic information outside of the A and B group, and the importance of Culicoides biting midge hosts as arbovirus vectors. Methods We reconstructed the genome of cCpun, a Cardinium strain from group C that naturally infects Culicoides punctatus, through Illumina sequencing of infected host specimens. Results The draft genome presented has high completeness, with BUSCO scores comparable to closed group A Cardinium genomes. Phylogenomic analysis based on concatenated single copy core proteins do not support Cardinium from arthropod hosts as a monophyletic group, with nematode Cardinium strains nested within the two groups infecting arthropod hosts. Analysis of the genome of cCpun revealed expansion of a variety of gene families classically considered important in symbiosis (e.g., ankyrin domain containing genes), and one set—characterized by DUF1703 domains—not previously associated with symbiotic lifestyle. This protein group encodes putative secreted nucleases, and the cCpun genome carried at least 25 widely divergent paralogs, 24 of which shared a common ancestor in the C group. The genome revealed no evidence in support of B vitamin provisioning to its haematophagous host, and indeed suggests Cardinium may be a net importer of biotin. Discussion These data indicate strains of Cardinium within nematodes cluster within Cardinium strains found in insects. The draft genome of cCpun further produces new hypotheses as to the interaction of the symbiont with the midge host, in particular the biological role of DUF1703 nuclease proteins that are predicted as being secreted by cCpun. In contrast, the coding content of this genome provides no support for a role for the symbiont in provisioning the host with B vitamins.
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Affiliation(s)
- Stefanos Siozios
- Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Jack Pilgrim
- Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Alistair C Darby
- Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Matthew Baylis
- Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK.,NIHR Health Protection Research Unit in Emerging and Zoonotic Infections (HPRU-EZI), University of Liverpool, Liverpool, UK
| | - Gregory D D Hurst
- Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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Beckmann JF, Bonneau M, Chen H, Hochstrasser M, Poinsot D, Merçot H, Weill M, Sicard M, Charlat S. The Toxin-Antidote Model of Cytoplasmic Incompatibility: Genetics and Evolutionary Implications. Trends Genet 2019; 35:175-185. [PMID: 30685209 DOI: 10.1016/j.tig.2018.12.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 10/27/2022]
Abstract
Wolbachia bacteria inhabit the cells of about half of all arthropod species, an unparalleled success stemming in large part from selfish invasive strategies. Cytoplasmic incompatibility (CI), whereby the symbiont makes itself essential to embryo viability, is the most common of these and constitutes a promising weapon against vector-borne diseases. After decades of theoretical and experimental struggle, major recent advances have been made toward a molecular understanding of this phenomenon. As pieces of the puzzle come together, from yeast and Drosophila fly transgenesis to CI diversity patterns in natural mosquito populations, it becomes clearer than ever that the CI induction and rescue stem from a toxin-antidote (TA) system. Further, the tight association of the CI genes with prophages provides clues to the possible evolutionary origin of this phenomenon and the levels of selection at play.
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Affiliation(s)
- John F Beckmann
- Auburn University, Department of Entomology and Plant Pathology, 301 Funchess Hall, Auburn, AL 36849, USA; Equal contribution
| | - Manon Bonneau
- Institut des Sciences de l'Evolution de Montpellier (ISEM), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Ecole Pratique des Hautes Etudes (EPHE), Institut de Recherche pour le Développement (IRD), Montpellier, France; Equal contribution
| | - Hongli Chen
- Yale University, Department of Molecular Biophysics and Biochemistry, 266 Whitney Avenue, New Haven, CT 06511, USA
| | - Mark Hochstrasser
- Yale University, Department of Molecular Biophysics and Biochemistry, 266 Whitney Avenue, New Haven, CT 06511, USA
| | - Denis Poinsot
- Université Rennes 1, Institut de Génétique, Environnement, et Protection des Plantes (IGEPP), Campus Beaulieu, 35042 Rennes, France
| | - Hervé Merçot
- Sorbonne Université, Université Pierre et Marie Curie (UPMC) Université Paris 06, CNRS, Institut de Biologie Paris Seine, Evolution Paris Seine (IBPS, EPS), 7-9 Quai St-Bernard, 75005 Paris, France
| | - Mylène Weill
- Institut des Sciences de l'Evolution de Montpellier (ISEM), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Ecole Pratique des Hautes Etudes (EPHE), Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Mathieu Sicard
- Institut des Sciences de l'Evolution de Montpellier (ISEM), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Ecole Pratique des Hautes Etudes (EPHE), Institut de Recherche pour le Développement (IRD), Montpellier, France.
| | - Sylvain Charlat
- CNRS, University of Lyon, Laboratoire de Biométrie et Biologie Evolutive, 16 rue Raphael Dubois, 69622 Villeurbanne, France.
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