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Nagamine K, Kanno Y, Sahara K, Fujimoto T, Yoshido A, Ishikawa Y, Terao M, Kageyama D, Shintani Y. Male-killing virus in a noctuid moth Spodoptera litura. Proc Natl Acad Sci U S A 2023; 120:e2312124120. [PMID: 37931114 PMCID: PMC10655585 DOI: 10.1073/pnas.2312124120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/28/2023] [Indexed: 11/08/2023] Open
Abstract
A female-biased sex ratio is considered advantageous for the cytoplasmic elements that inhabit sexually reproducing organisms. There are numerous examples of bacterial symbionts in the arthropod cytoplasm that bias the host sex ratio toward females through various means, including feminization and male killing. Recently, maternally inherited RNA viruses belonging to the family Partitiviridae were found to cause male killing in moths and flies, but it was unknown whether male-killing viruses were restricted to Partitiviridae or could be found in other taxa. Here, we provide compelling evidence that a maternally inherited RNA virus, Spodoptera litura male-killing virus (SlMKV), selectively kills male embryos of the tobacco caterpillar Spodoptera litura, resulting in all-female broods. SlMKV injected into uninfected S. litura can also be inherited maternally and causes male killing. SlMKV has five genomic segments encoding seven open reading frames, has no homolog of known male-killing genes, and belongs to an unclassified group of arthropod-specific viruses closely related to Tolivirales. When transinfected into larvae, both male and female recipients allow SlMKV to proliferate, but only males die at the pupal stage. The viral RNA levels in embryonic and pupal male killing suggest that the mechanism of male killing involves the constitutive expression of viral products that are specifically lethal to males, rather than the male-specific expression of viral products. Our results, together with recent findings on male-killing partiti-like viruses, suggest that diverse viruses in arthropods tend to acquire male killing independently and that such viruses may be important components of intragenomic conflict in arthropods.
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Affiliation(s)
- Keisuke Nagamine
- Department of Environmental and Horticultural Sciences, Minami Kyushu University, Miyakonojo, Miyazaki885-0035, Japan
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki305-0851, Japan
| | - Yoshiaki Kanno
- Department of Environmental and Horticultural Sciences, Minami Kyushu University, Miyakonojo, Miyazaki885-0035, Japan
| | - Ken Sahara
- Faculty of Agriculture, Iwate University, Morioka, Iwate020-8550, Japan
| | - Toshiaki Fujimoto
- Faculty of Agriculture, Iwate University, Morioka, Iwate020-8550, Japan
| | - Atsuo Yoshido
- Faculty of Agriculture, Iwate University, Morioka, Iwate020-8550, Japan
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, České Budějovice370 05, Czech Republic
| | - Yukio Ishikawa
- Faculty of Agriculture, Setsunan University, Hirakata, Osaka573-0101, Japan
| | - Misato Terao
- Department of Environmental and Horticultural Sciences, Minami Kyushu University, Miyakonojo, Miyazaki885-0035, Japan
| | - Daisuke Kageyama
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki305-0851, Japan
| | - Yoshinori Shintani
- Department of Environmental and Horticultural Sciences, Minami Kyushu University, Miyakonojo, Miyazaki885-0035, Japan
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2
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Morrow JL, Schneider DI, Klasson L, Janitz C, Miller WJ, Riegler M. Parallel Sequencing of Wolbachia wCer2 from Donor and Novel Hosts Reveals Multiple Incompatibility Factors and Genome Stability after Host Transfers. Genome Biol Evol 2021; 12:720-735. [PMID: 32163151 PMCID: PMC7259677 DOI: 10.1093/gbe/evaa050] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2020] [Indexed: 12/11/2022] Open
Abstract
The application of Wolbachia in insect pest and vector control requires the establishment of genotypically stable host associations. The cytoplasmic incompatibility (CI) inducing Wolbachia strain wCer2 naturally occurs in the cherry fruit fly Rhagoletis cerasi as co-infection with other strains and was transferred to other fruit fly species by embryonic microinjections. We obtained wCer2 genome data from its native and three novel hosts, Drosophila simulans, Drosophila melanogaster, and Ceratitis capitata and assessed its genome stability, characteristics, and CI factor (cif) genes. De novo assembly was successful from Wolbachia cell-enriched singly infected D. simulans embryos, with minimal host and other bacterial genome traces. The low yield of Wolbachia sequence reads from total genomic extracts of one multiply infected R. cerasi pupa and one singly infected C. capitata adult limited de novo assemblies but was sufficient for comparative analyses. Across hosts wCer2 was stable in genome synteny and content. Polymorphic nucleotide sites were found in wCer2 of each host; however, only one nucleotide was different between R. cerasi and C. capitata, and none between replicated D. simulans lines. The wCer2 genome is highly similar to wAu (D. simulans), wMel (D. melanogaster), and wRec (Drosophila recens). In contrast to wMel and wRec (each with one cif gene pair) and wAu (without any cif genes), wCer2 has three pairs of Type I cif genes, and one Type V cifB gene without a cifA complement. This may explain previously reported CI patterns of wCer2, including incomplete rescue of its own CI modification in three novel host species.
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Affiliation(s)
- Jennifer L Morrow
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Daniela I Schneider
- Division of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Austria.,Department of Epidemiology of Microbial Diseases, Yale University, New Haven, Connecticut
| | - Lisa Klasson
- Molecular Evolution, Department of Cell and Molecular Biology, Uppsala University, Sweden
| | - Caroline Janitz
- Next Generation Sequencing Facility, Western Sydney University, Penrith, NSW, Australia
| | - Wolfgang J Miller
- Division of Cell & Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Austria
| | - Markus Riegler
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
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3
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Cruz MA, Magalhães S, Sucena É, Zélé F. Wolbachia and host intrinsic reproductive barriers contribute additively to postmating isolation in spider mites. Evolution 2021; 75:2085-2101. [PMID: 34156702 DOI: 10.1111/evo.14286] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 05/04/2021] [Accepted: 05/20/2021] [Indexed: 12/27/2022]
Abstract
Wolbachia are maternally-inherited bacteria that induce cytoplasmic incompatibility in many arthropod species. However, the ubiquity of this isolation mechanism for host speciation processes remains elusive, as only few studies have examined Wolbachia-induced incompatibilities when host populations are not genetically compatible. Here, we used three populations of two genetically differentiated colour forms of the haplodiploid spider mite Tetranychus urticae to dissect the interaction between Wolbachia-induced and host-associated incompatibilities, and their relative contribution to postmating isolation. We found that these two sources of incompatibility act through different mechanisms in an additive fashion. Host-associated incompatibility contributes 1.5 times more than Wolbachia-induced incompatibility in reducing hybrid production, the former through an overproduction of haploid sons at the expense of diploid daughters (ca. 75% decrease) and the latter by increasing the embryonic mortality of daughters (by ca. 49%). Furthermore, regardless of cross direction, we observed near-complete F1 hybrid sterility and complete F2 hybrid breakdown between populations of the two forms, but Wolbachia did not contribute to this outcome. We thus show mechanistic independence and an additive nature of host-intrinsic and Wolbachia-induced sources of isolation. Wolbachia may contribute to reproductive isolation in this system, thereby potentially affecting host differentiation and distribution in the field.
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Affiliation(s)
- Miguel A Cruz
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Edificio C2, 3° Piso Campo Grande, Lisboa, Portugal
| | - Sara Magalhães
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Edificio C2, 3° Piso Campo Grande, Lisboa, Portugal.,Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa, Portugal
| | - Élio Sucena
- Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa, Portugal.,Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Flore Zélé
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Edificio C2, 3° Piso Campo Grande, Lisboa, Portugal.,Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa, Portugal.,ISEM, University of Montpellier, CNRS, IRD, EPHE, Montpellier, France
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4
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Lv N, Peng J, Chen XY, Guo CF, Sang W, Wang XM, Ahmed MZ, Xu YY, Qiu BL. Antagonistic interaction between male-killing and cytoplasmic incompatibility induced by Cardinium and Wolbachia in the whitefly, Bemisia tabaci. Insect Sci 2021; 28:330-346. [PMID: 32339445 DOI: 10.1111/1744-7917.12793] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/30/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Cardinium and Wolbachia are maternally inherited bacterial symbionts of arthropods that can manipulate host reproduction by increasing the fitness of infected females. Here, we report that Cardinium and Wolbachia coinfection induced male-killing and cytoplasmic incompatibility (CI) when they coexisted in a cryptic species of whitefly, Bemisia tabaci Asia II7. Cardinium and Wolbachia symbionts were either singly or simultaneously localized in the bacteriocytes placed in the abdomen of B. tabaci nymphs and adults. Cardinium-Wolbachia coinfection induced male-killing and resulted in a higher female sex ratio in the intraspecific amphigenetic progeny of Asia II7 ICWH and ICWL lines; interestingly, male-killing induction was enhanced with increased Cardinium titer. Moreover, single infection of Wolbachia induced partial CI in the Asia II7 IW line and resulted in reduced fecundity, higher embryonic mortality, and lower female sex ratio. The uninfected Asia II7 IU line had significantly higher fecundity, lower embryonic and nymphal mortalities, and a lower level of CI than both the Wolbachia-infected Asia II7 IW line and the Cardinium-Wolbachia-coinfected Asia II7 ICWH line. Our findings indicate that Cardinium-Wolbachia coinfection induced male-killing, which may have had antagonistic effects on Wolbachia-induced CI in the Asia II7 whiteflies. For the first time, our study revealed that B. tabaci Asia II7 reproduction is co-manipulated by Cardinium and Wolbachia endosymbionts.
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Affiliation(s)
- Ning Lv
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China
- Engineering Research Center of Biocontrol, Ministry of Education, Guangzhou, China
| | - Jing Peng
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China
- Engineering Research Center of Biocontrol, Ministry of Education, Guangzhou, China
| | - Xin-Yi Chen
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China
- Engineering Research Center of Biocontrol, Ministry of Education, Guangzhou, China
| | - Chang-Fei Guo
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China
- Engineering Research Center of Biocontrol, Ministry of Education, Guangzhou, China
| | - Wen Sang
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China
- Engineering Research Center of Biocontrol, Ministry of Education, Guangzhou, China
| | - Xing-Min Wang
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China
- Engineering Research Center of Biocontrol, Ministry of Education, Guangzhou, China
- Maoming Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Maoming, Guangdong Province, China
| | - Muhammad Z Ahmed
- Florida Department of Agriculture and Consumer Services, 1911 SW 34th Street, Gainesville, USA
| | - Yong-Yu Xu
- College of Plant Protection, Shandong Agricultural University, Taian, Shandong Province, China
| | - Bao-Li Qiu
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China
- Engineering Research Center of Biocontrol, Ministry of Education, Guangzhou, China
- Maoming Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Maoming, Guangdong Province, China
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5
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Shan HW, Luan JB, Liu YQ, Douglas AE, Liu SS. The inherited bacterial symbiont Hamiltonella influences the sex ratio of an insect host. Proc Biol Sci 2019; 286:20191677. [PMID: 31744432 PMCID: PMC6892053 DOI: 10.1098/rspb.2019.1677] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/18/2019] [Indexed: 01/13/2023] Open
Abstract
In many intracellular symbioses, the microbial symbionts provide nutrients advantageous to the host. However, the function of Hamiltonella defensa, a symbiotic bacterium localized in specialized host cells (bacteriocytes) of a whitefly Bemisia tabaci, is uncertain. We eliminate this bacterium from its whitefly host by two alternative methods: heat treatment and antibiotics. The sex ratio of the host progeny and subsequent generations of Hamiltonella-free females was skewed from 1 : 1 (male : female) to an excess of males, often exceeding a ratio of 20 : 1. B. tabaci is haplodiploid, with diploid females derived from fertilized eggs and haploid males from unfertilized eggs. The Hamiltonella status of the insect did not affect copulation frequency or sperm reserve in the spermathecae, indicating that the male-biased sex ratio is unlikely due to the limitation of sperm but likely to be associated with events subsequent to sperm transfer to the female insects, such as failure in fertilization. The host reproductive response to Hamiltonella elimination is consistent with two alternative processes: adaptive shift in sex allocation by females and a constitutive compensatory response of the insect to Hamiltonella-mediated manipulation. Our findings suggest that a bacteriocyte symbiont influences the reproductive output of female progeny in a haplodiploid insect.
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Affiliation(s)
- Hong-Wei Shan
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Jun-Bo Luan
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Yin-Quan Liu
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Angela E. Douglas
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Shu-Sheng Liu
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou, People's Republic of China
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6
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Schebeck M, Feldkirchner L, Stauffer C, Schuler H. Dynamics of an Ongoing Wolbachia Spread in the European Cherry Fruit Fly, Rhagoletis cerasi (Diptera: Tephritidae). Insects 2019; 10:insects10060172. [PMID: 31208002 PMCID: PMC6627601 DOI: 10.3390/insects10060172] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/06/2019] [Accepted: 06/11/2019] [Indexed: 11/20/2022]
Abstract
Numerous terrestrial arthropods are infected with the alphaproteobacterium Wolbachia. This endosymbiont is usually transmitted vertically from infected females to their offspring and can alter the reproduction of hosts through various manipulations, like cytoplasmic incompatibility (CI), enhancing its spread in new host populations. Studies on the spatial and temporal dynamics of Wolbachia under natural conditions are scarce. Here, we analyzed Wolbachia infection frequencies in populations of the European cherry fruit fly, Rhagoletis cerasi (L.), in central Germany—an area of an ongoing spread of the CI-inducing strain wCer2. In total, 295 individuals from 19 populations were PCR-screened for the presence of wCer2 and their mitochondrial haplotype. Results were compared with historic data to understand the infection dynamics of the ongoing wCer2 invasion. An overall wCer2 infection frequency of about 30% was found, ranging from 0% to 100% per population. In contrast to an expected smooth transition from wCer2-infected to completely wCer2-uninfected populations, a relatively scattered infection pattern across geography was observed. Moreover, a strong Wolbachia-haplotype association was detected, with only a few rare misassociations. Our results show a complex dynamic of an ongoing Wolbachia spread in natural field populations of R. cerasi.
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Affiliation(s)
- Martin Schebeck
- Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences Vienna, BOKU, Peter-Jordan-Straße 82/I, A-1190 Vienna, Austria.
| | - Lukas Feldkirchner
- Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences Vienna, BOKU, Peter-Jordan-Straße 82/I, A-1190 Vienna, Austria.
| | - Christian Stauffer
- Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences Vienna, BOKU, Peter-Jordan-Straße 82/I, A-1190 Vienna, Austria.
| | - Hannes Schuler
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Universitätsplatz 5, I-39100 Bozen-Bolzano, Italy.
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7
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Lindsey ARI, Rice DW, Bordenstein SR, Brooks AW, Bordenstein SR, Newton ILG. Evolutionary Genetics of Cytoplasmic Incompatibility Genes cifA and cifB in Prophage WO of Wolbachia. Genome Biol Evol 2018; 10:434-451. [PMID: 29351633 PMCID: PMC5793819 DOI: 10.1093/gbe/evy012] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2018] [Indexed: 12/20/2022] Open
Abstract
The bacterial endosymbiont Wolbachia manipulates arthropod reproduction to facilitate its maternal spread through host populations. The most common manipulation is cytoplasmic incompatibility (CI): Wolbachia-infected males produce modified sperm that cause embryonic mortality, unless rescued by embryos harboring the same Wolbachia. The genes underlying CI, cifA and cifB, were recently identified in the eukaryotic association module of Wolbachia’s prophage WO. Here, we use transcriptomic and genomic approaches to address three important evolutionary facets of the cif genes. First, we assess whether or not cifA and cifB comprise a classic toxin–antitoxin operon in wMel and show that the two genes exhibit striking, transcriptional differences across host development. They can produce a bicistronic message despite a predicted hairpin termination element in their intergenic region. Second, cifA and cifB strongly coevolve across the diversity of phage WO. Third, we provide new domain and functional predictions across homologs within Wolbachia, and show that amino acid sequences vary substantially across the genus. Finally, we investigate conservation of cifA and cifB and find frequent degradation and loss of the genes in strains that no longer induce CI. Taken together, we demonstrate that cifA and cifB exhibit complex transcriptional regulation in wMel, provide functional annotations that broaden the potential mechanisms of CI induction, and report recurrent erosion of cifA and cifB in non-CI strains, thus expanding our understanding of the most widespread form of reproductive parasitism.
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Affiliation(s)
| | - Danny W Rice
- Department of Biology, Indiana University, Bloomington
| | | | - Andrew W Brooks
- Department of Biological Sciences, Vanderbilt University.,Vanderbilt Genetics Institute, Vanderbilt University
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University.,Vanderbilt Genetics Institute, Vanderbilt University.,Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University.,Department of Pathology, Microbiology and Immunology, Vanderbilt University
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8
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Newton ILG, Clark ME, Kent BN, Bordenstein SR, Qu J, Richards S, Kelkar YD, Werren JH. Comparative Genomics of Two Closely Related Wolbachia with Different Reproductive Effects on Hosts. Genome Biol Evol 2016; 8:1526-42. [PMID: 27189996 PMCID: PMC4898810 DOI: 10.1093/gbe/evw096] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Wolbachia pipientis are obligate intracellular bacteria commonly found in many arthropods. They can induce various reproductive alterations in hosts, including cytoplasmic incompatibility, male-killing, feminization, and parthenogenetic development, and can provide host protection against some viruses and other pathogens. Wolbachia differ from many other primary endosymbionts in arthropods because they undergo frequent horizontal transmission between hosts and are well known for an abundance of mobile elements and relatively high recombination rates. Here, we compare the genomes of two closely related Wolbachia (with 0.57% genome-wide synonymous divergence) that differ in their reproductive effects on hosts. wVitA induces a sperm-egg incompatibility (also known as cytoplasmic incompatibility) in the parasitoid insect Nasonia vitripennis, whereas wUni causes parthenogenetic development in a different parasitoid, Muscidifurax uniraptor Although these bacteria are closely related, the genomic comparison reveals rampant rearrangements, protein truncations (particularly in proteins predicted to be secreted), and elevated substitution rates. These changes occur predominantly in the wUni lineage, and may be due in part to adaptations by wUni to a new host environment, or its phenotypic shift to parthenogenesis induction. However, we conclude that the approximately 8-fold elevated synonymous substitution rate in wUni is due to a either an elevated mutation rate or a greater number of generations per year in wUni, which occurs in semitropical host species. We identify a set of genes whose loss or pseudogenization in the wUni lineage implicates them in the phenotypic shift from cytoplasmic incompatibility to parthenogenesis induction. Finally, comparison of these closely related strains allows us to determine the fine-scale mutation patterns in Wolbachia Although Wolbachia are AT rich, mutation probabilities estimated from 4-fold degenerate sites are not AT biased, and predict an equilibrium AT content much less biased than observed (57-50% AT predicted vs. 76% current content at degenerate sites genome wide). The contrast suggests selection for increased AT content within Wolbachia genomes.
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Affiliation(s)
| | | | - Bethany N Kent
- Department of Biological Sciences, Vanderbilt University
| | - Seth R Bordenstein
- Department of Biological Sciences, Vanderbilt University Department of Pathology, Microbiology and Immunology, Vanderbilt University
| | - Jiaxin Qu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Stephen Richards
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Yogeshwar D Kelkar
- Department of Biostatistics and Computational Biology, University of Rochester
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Hamm CA, Begun DJ, Vo A, Smith CCR, Saelao P, Shaver AO, Jaenike J, Turelli M. Wolbachia do not live by reproductive manipulation alone: infection polymorphism in Drosophila suzukii and D. subpulchrella. Mol Ecol 2014; 23:4871-85. [PMID: 25156506 DOI: 10.1111/mec.12901] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/09/2014] [Accepted: 08/15/2014] [Indexed: 01/30/2023]
Abstract
Drosophila suzukii recently invaded North America and Europe. Populations in Hawaii, California, New York and Nova Scotia are polymorphic for Wolbachia, typically with <20% infection frequency. The Wolbachia in D. suzukii, denoted wSuz, is closely related to wRi, the variant prevalent in continental populations of D. simulans. wSuz is also nearly identical to Wolbachia found in D. subpulchrella, plausibly D. suzukii's sister species. This suggests vertical Wolbachia transmission through cladogenesis ('cladogenic transmission'). The widespread occurrence of 7-20% infection frequencies indicates a stable polymorphism. wSuz is imperfectly maternally transmitted, with wild infected females producing on average 5-10% uninfected progeny. As expected from its low frequency, wSuz produces no cytoplasmic incompatibility (CI), that is, no increased embryo mortality when infected males mate with uninfected females, and no appreciable sex-ratio distortion. The persistence of wSuz despite imperfect maternal transmission suggests positive fitness effects. Assuming a balance between selection and imperfect transmission, we expect a fitness advantage on the order of 20%. Unexpectedly, Wolbachia-infected females produce fewer progeny than do uninfected females. We do not yet understand the maintenance of wSuz in D. suzukii. The absence of detectable CI in D. suzukii and D. subpulchrella makes it unlikely that CI-based mechanisms could be used to control this species without transinfection using novel Wolbachia. Contrary to their reputation as horizontally transmitted reproductive parasites, many Wolbachia infections are acquired through introgression or cladogenesis and many cause no appreciable reproductive manipulation. Such infections, likely to be mutualistic, may be central to understanding the pervasiveness of Wolbachia among arthropods.
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Affiliation(s)
- Christopher A Hamm
- Department of Evolution and Ecology, University of California, One Shields Avenue, Davis, CA, 95616, USA
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10
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Abstract
The bacterial endosymbiont Wolbachia manipulates arthropod host biology in numerous ways, including sex ratio distortion and differential offspring survival. These bacteria infect a vast array of arthropods, some of which pose serious agricultural and human health threats. Wolbachia-mediated phenotypes such as cytoplasmic incompatibility and/or pathogen interference can be used for vector and disease control; however, many medically important vectors and important agricultural species are uninfected or are infected with strains of Wolbachia that do not elicit phenotypes desirable for disease or pest control. The ability to transfer strains of Wolbachia into new hosts (transinfection) can create novel Wolbachia-host associations. Transinfection has two primary benefits. First, Wolbachia-host interactions can be examined to tease apart the influence of the host and bacteria on phenotypes. Second, desirable phenotypes induced by Wolbachia in a particular insect can be transferred to another recipient host. This can allow the manipulation of insect populations that transmit pathogens or detrimentally affect agriculture. As such, transinfection is a valuable tool to explore Wolbachia biology and control arthropod-borne disease. The present review summarizes what is currently known about Wolbachia transinfection methods and applications. We also provide a comprehensive list of published successful and unsuccessful Wolbachia transinfection attempts.
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Affiliation(s)
- G L Hughes
- The Huck Institutes of The Life Sciences, The Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA; Department of Entomology, Pennsylvania State University, University Park, PA, USA
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Abstract
The best-known members of the bacterial genus Rickettsia are associates of blood-feeding arthropods that are pathogenic when transmitted to vertebrates. These species include the agents of acute human disease such as typhus and Rocky Mountain spotted fever. However, many other Rickettsia have been uncovered in recent surveys of bacteria associated with arthropods and other invertebrates; the hosts of these bacteria have no relationship with vertebrates. It is therefore perhaps more appropriate to consider Rickettsia as symbionts that are transmitted vertically in invertebrates, and secondarily as pathogens of vertebrates. In this review, we highlight the emerging diversity of Rickettsia species that are not associated with vertebrate pathogenicity. Phylogenetic analysis suggests multiple transitions between symbionts that are transmitted strictly vertically and those that exhibit mixed (horizontal and vertical) transmission. Rickettsia may thus be an excellent model system in which to study the evolution of transmission pathways. We also focus on the emergence of Rickettsia as a diverse reproductive manipulator of arthropods, similar to the closely related Wolbachia, including strains associated with male-killing, parthenogenesis, and effects on fertility. We emphasize some outstanding questions and potential research directions, and suggest ways in which the study of non-pathogenic Rickettsia can advance our understanding of their disease-causing relatives.
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Affiliation(s)
- Steve J Perlman
- Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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