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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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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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