1
|
Schober I, Bunk B, Carril G, Freese HM, Ojeda N, Riedel T, Meier-Kolthoff JP, Göker M, Spröer C, Flores-Herrera PA, Nourdin-Galindo G, Gómez F, Cárdenas C, Vásquez-Ponce F, Labra A, Figueroa J, Olivares-Pacheco J, Nübel U, Sikorski J, Marshall SH, Overmann J. Ongoing diversification of the global fish pathogen Piscirickettsia salmonis through genetic isolation and transposition bursts. THE ISME JOURNAL 2023; 17:2247-2258. [PMID: 37853183 PMCID: PMC10689435 DOI: 10.1038/s41396-023-01531-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 09/28/2023] [Accepted: 10/02/2023] [Indexed: 10/20/2023]
Abstract
The management of bacterial pathogens remains a key challenge of aquaculture. The marine gammaproteobacterium Piscirickettsia salmonis is the etiological agent of piscirickettsiosis and causes multi-systemic infections in different salmon species, resulting in considerable mortality and substantial commercial losses. Here, we elucidate its global diversity, evolution, and selection during human interventions. Our comprehensive analysis of 73 closed, high quality genome sequences covered strains from major outbreaks and was supplemented by an analysis of all P. salmonis 16S rRNA gene sequences and metagenomic reads available in public databases. Genome comparison showed that Piscirickettsia comprises at least three distinct, genetically isolated species of which two showed evidence for continuing speciation. However, at least twice the number of species exist in marine fish or seawater. A hallmark of Piscirickettsia diversification is the unprecedented amount and diversity of transposases which are particularly active in subgroups undergoing rapid speciation and are key to the acquisition of novel genes and to pseudogenization. Several group-specific genes are involved in surface antigen synthesis and may explain the differences in virulence between strains. However, the frequent failure of antibiotic treatment of piscirickettsiosis outbreaks cannot be explained by horizontal acquisition of resistance genes which so far occurred only very rarely. Besides revealing a dynamic diversification of an important pathogen, our study also provides the data for improving its surveillance, predicting the emergence of novel lineages, and adapting aquaculture management, and thereby contributes towards the sustainability of salmon farming.
Collapse
Affiliation(s)
- Isabel Schober
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Gabriela Carril
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Heike M Freese
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Nicolás Ojeda
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Thomas Riedel
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
- German Center for Infection Research (DZIF), Partner Site Braunschweig-Hannover, Braunschweig, Germany
| | - Jan P Meier-Kolthoff
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Markus Göker
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Patricio A Flores-Herrera
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Guillermo Nourdin-Galindo
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Fernando Gómez
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Constanza Cárdenas
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- Núcleo Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Campus Curauma, Valparaíso, Chile
| | - Felipe Vásquez-Ponce
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Alvaro Labra
- Laboratorio de Patógenos Acuícolas, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Jaime Figueroa
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Jorge Olivares-Pacheco
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- Núcleo Milenio para la Investigación Colaborativa en Resistencia Antimicrobiana (MICROB-R), Santiago, Chile
| | - Ulrich Nübel
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
- German Center for Infection Research (DZIF), Partner Site Braunschweig-Hannover, Braunschweig, Germany
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Johannes Sikorski
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Sergio H Marshall
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- Núcleo Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Campus Curauma, Valparaíso, Chile
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.
- German Center for Infection Research (DZIF), Partner Site Braunschweig-Hannover, Braunschweig, Germany.
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.
| |
Collapse
|
2
|
Halter T, Köstlbacher S, Collingro A, Sixt BS, Tönshoff ER, Hendrickx F, Kostanjšek R, Horn M. Ecology and evolution of chlamydial symbionts of arthropods. ISME COMMUNICATIONS 2022; 2:45. [PMID: 37938728 PMCID: PMC9723776 DOI: 10.1038/s43705-022-00124-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/31/2022] [Accepted: 04/08/2022] [Indexed: 05/08/2023]
Abstract
The phylum Chlamydiae consists of obligate intracellular bacteria including major human pathogens and diverse environmental representatives. Here we investigated the Rhabdochlamydiaceae, which is predicted to be the largest and most diverse chlamydial family, with the few described members known to infect arthropod hosts. Using published 16 S rRNA gene sequence data we identified at least 388 genus-level lineages containing about 14 051 putative species within this family. We show that rhabdochlamydiae are mainly found in freshwater and soil environments, suggesting the existence of diverse, yet unknown hosts. Next, we used a comprehensive genome dataset including metagenome assembled genomes classified as members of the family Rhabdochlamydiaceae, and we added novel complete genome sequences of Rhabdochlamydia porcellionis infecting the woodlouse Porcellio scaber, and of 'Candidatus R. oedothoracis' associated with the linyphiid dwarf spider Oedothorax gibbosus. Comparative analysis of basic genome features and gene content with reference genomes of well-studied chlamydial families with known host ranges, namely Parachlamydiaceae (protist hosts) and Chlamydiaceae (human and other vertebrate hosts) suggested distinct niches for members of the Rhabdochlamydiaceae. We propose that members of the family represent intermediate stages of adaptation of chlamydiae from protists to vertebrate hosts. Within the genus Rhabdochlamydia, pronounced genome size reduction could be observed (1.49-1.93 Mb). The abundance and genomic distribution of transposases suggests transposable element expansion and subsequent gene inactivation as a mechanism of genome streamlining during adaptation to new hosts. This type of genome reduction has never been described before for any member of the phylum Chlamydiae. This study provides new insights into the molecular ecology, genomic diversity, and evolution of representatives of one of the most divergent chlamydial families.
Collapse
Affiliation(s)
- Tamara Halter
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Doctoral School in Microbiology and Environmental Science, University of Vienna, Vienna, Austria
| | - Stephan Köstlbacher
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Doctoral School in Microbiology and Environmental Science, University of Vienna, Vienna, Austria
| | - Astrid Collingro
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Barbara S Sixt
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Elena R Tönshoff
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich (ETH), Zurich, Switzerland
| | | | - Rok Kostanjšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Matthias Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.
| |
Collapse
|
3
|
Selberherr E, Penz T, König L, Conrady B, Siegl A, Horn M, Schmitz-Esser S. The life cycle-dependent transcriptional profile of the obligate intracellular amoeba symbiont Amoebophilus asiaticus. FEMS Microbiol Ecol 2022; 98:6499296. [PMID: 34999767 PMCID: PMC8831229 DOI: 10.1093/femsec/fiac001] [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] [Received: 10/29/2021] [Revised: 12/22/2021] [Accepted: 01/04/2022] [Indexed: 12/04/2022] Open
Abstract
Free-living amoebae often harbor obligate intracellular bacterial symbionts. Amoebophilus (A.) asiaticus is a representative of a lineage of amoeba symbionts in the phylum Bacteroidota. Here, we analyse the transcriptome of A. asiaticus strain 5a2 at four time points during its infection cycle and replication within the Acanthamoeba host using RNA sequencing. Our results reveal a dynamic transcriptional landscape throughout different A. asiaticus life cycle stages. Many intracellular bacteria and pathogens utilize eukaryotic-like proteins (ELPs) for host cell interaction and the A. asiaticus 5a2 genome shows a particularly high abundance of ELPs. We show the expression of all genes encoding ELPs and found many ELPs to be differentially expressed. At the replicative stage of A. asiaticus, ankyrin repeat proteins and tetratricopeptide/Sel1-like repeat proteins were upregulated. At the later time points, high expression levels of a type 6 secretion system that likely prepares for a new infection cycle after lysing its host, were found. This study reveals comprehensive insights into the intracellular lifestyle of A. asiaticus and highlights candidate genes for host cell interaction. The results from this study have implications for other intracellular bacteria such as other amoeba-associated bacteria and the arthropod symbionts Cardinium forming the sister lineage of A. asiaticus.
Collapse
Affiliation(s)
- E Selberherr
- Unit of Food Microbiology, Institute of Food Safety, Food Technology and Veterinary Public Health, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Austria
| | - T Penz
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.,current affiliation: CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - L König
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - B Conrady
- Department of Veterinary and Animal Science, University of Copenhagen, Denmark
| | - A Siegl
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - M Horn
- Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - S Schmitz-Esser
- Department of Animal Science, Iowa State University, Ames, USA
| |
Collapse
|
4
|
Garber AI, Kupper M, Laetsch DR, Weldon SR, Ladinsky MS, Bjorkman PJ, McCutcheon JP. The Evolution of Interdependence in a Four-Way Mealybug Symbiosis. Genome Biol Evol 2021; 13:evab123. [PMID: 34061185 PMCID: PMC8331144 DOI: 10.1093/gbe/evab123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2021] [Indexed: 01/03/2023] Open
Abstract
Mealybugs are insects that maintain intracellular bacterial symbionts to supplement their nutrient-poor plant sap diets. Some mealybugs have a single betaproteobacterial endosymbiont, a Candidatus Tremblaya species (hereafter Tremblaya) that alone provides the insect with its required nutrients. Other mealybugs have two nutritional endosymbionts that together provision these same nutrients, where Tremblaya has gained a gammaproteobacterial partner that resides in its cytoplasm. Previous work had established that Pseudococcus longispinus mealybugs maintain not one but two species of gammaproteobacterial endosymbionts along with Tremblaya. Preliminary genomic analyses suggested that these two gammaproteobacterial endosymbionts have large genomes with features consistent with a relatively recent origin as insect endosymbionts, but the patterns of genomic complementarity between members of the symbiosis and their relative cellular locations were unknown. Here, using long-read sequencing and various types of microscopy, we show that the two gammaproteobacterial symbionts of P. longispinus are mixed together within Tremblaya cells, and that their genomes are somewhat reduced in size compared with their closest nonendosymbiotic relatives. Both gammaproteobacterial genomes contain thousands of pseudogenes, consistent with a relatively recent shift from a free-living to an endosymbiotic lifestyle. Biosynthetic pathways of key metabolites are partitioned in complex interdependent patterns among the two gammaproteobacterial genomes, the Tremblaya genome, and horizontally acquired bacterial genes that are encoded on the mealybug nuclear genome. Although these two gammaproteobacterial endosymbionts have been acquired recently in evolutionary time, they have already evolved codependencies with each other, Tremblaya, and their insect host.
Collapse
Affiliation(s)
- Arkadiy I Garber
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
- Biodesign Center for Mechanisms of Evolution and School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Maria Kupper
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
- Biodesign Center for Mechanisms of Evolution and School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Dominik R Laetsch
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Stephanie R Weldon
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
| | - Mark S Ladinsky
- Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Pamela J Bjorkman
- Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - John P McCutcheon
- Division of Biological Sciences, University of Montana, Missoula, Montana, USA
- Biodesign Center for Mechanisms of Evolution and School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| |
Collapse
|
5
|
Wang H, Zhang H, Zhong Z, Sun Y, Wang M, Chen H, Zhou L, Cao L, Lian C, Li C. Molecular analyses of the gill symbiosis of the bathymodiolin mussel Gigantidas platifrons. iScience 2020; 24:101894. [PMID: 33364583 PMCID: PMC7750550 DOI: 10.1016/j.isci.2020.101894] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/07/2020] [Accepted: 12/02/2020] [Indexed: 11/29/2022] Open
Abstract
Although the deep-sea bathymodiolin mussels have been intensively studied as a model of animal-bacteria symbiosis, it remains challenging to assess the host-symbiont interactions due to the complexity of the symbiotic tissue-the gill. Using cold-seep mussel Gigantidas platifrons as a model, we isolated the symbiont harboring bacteriocytes and profiled the transcriptomes of the three major parts of the symbiosis-the gill, the bacteriocyte, and the symbiont. This breakdown of the complex symbiotic tissue allowed us to characterize the host-symbiont interactions further. Our data showed that the gill's non-symbiotic parts play crucial roles in maintaining and protecting the symbiosis; the bacteriocytes supply the symbiont with metabolites, control symbiont population, and shelter the symbiont from phage infection; the symbiont dedicates to the methane oxidation and energy production. This study demonstrates that the bathymodiolin symbiosis interacts at the tissue, cellular, and molecular level, maintaining high efficiency and harmonic chemosynthetic micro niche.
Collapse
Affiliation(s)
- Hao Wang
- Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Huan Zhang
- Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Zhaoshan Zhong
- Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan Sun
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China.,Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Minxiao Wang
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China.,Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Hao Chen
- Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Li Zhou
- Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Lei Cao
- Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Chao Lian
- Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China
| | - Chaolun Li
- Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, P. R. China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, P. R. China.,Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, P. R. China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
6
|
Zhang X, Xiao S, Jiang X, Li Y, Fan Z, Yu Y, Wang P, Li D, Zhao X, Liu C. Genomic characterization of Escherichia coli LCT-EC001, an extremely multidrug-resistant strain with an amazing number of resistance genes. Gut Pathog 2019; 11:25. [PMID: 31139265 PMCID: PMC6528259 DOI: 10.1186/s13099-019-0298-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 04/13/2019] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Multidrug resistance is a growing global public health threat with far more serious consequences than generally anticipated. In this study, we investigated the antibiotic resistance and genomic traits of a clinical strain of Escherichia coli LCT-EC001. RESULTS LCT-EC001 was resistant to 16 kinds of widely used antibiotics, including fourth-generation cephalosporins and carbapenems. In total, up to 68 determinants associated with antibiotic resistance were identified, including 8 beta-lactamase genes (notably producing ESBLs and KPCs), 31 multidrug efflux system genes, 6 outer membrane transport system genes, 4 aminoglycoside-modifying enzyme genes, 10 two-component regulatory system genes, and 9 other enzyme or transcriptional regulator genes, covering nearly all known drug-resistance mechanisms in E. coli. More than half of the resistance genes were located close to mobile genetic elements, such as plasmids, transposons, genomics islands, and insertion sequences. Phylogenetic analysis revealed that this strain may have evolved from E. coli K-12 but is a completely new MLST type. CONCLUSIONS Antibiotic resistance was extremely severe in E. coli LCT-EC001, mainly due to mobile genetic elements that allowed the gain of a large quantity of resistance genes. The antibiotic resistance genes of E. coli LCT-EC001 can probably be transferred to other bacteria. To the best of our knowledge, this is the first report of a strain of E. coli which has such a large amount of antibiotic resistance genes. Apart from providing an E. coli reference genome with an extremely high multidrug-resistant background for future analyses, this work also offers a strategy for investigating the complement and characteristics of genes contributing to drug resistance at the whole-genome level.
Collapse
Affiliation(s)
- Xuelin Zhang
- Respiratory Diseases Department, The Second Medical Center of PLA General Hospital, Beijing, 100853 China
- Hyperbaric Oxygen Department, The First Medical Center of PLA General Hospital, Beijing, 100853 China
| | - Saisong Xiao
- Department of Anesthesiology, Dongzhimen Hospital Beijing University of Chinese Medicine, Beijing, 100700 China
| | - Xuege Jiang
- Respiratory Diseases Department, The Second Medical Center of PLA General Hospital, Beijing, 100853 China
| | - Yun Li
- Respiratory Diseases Department, The Eighth Medical Center of PLA General Hospital, Beijing, 100091 China
| | - Zhongyi Fan
- Respiratory Diseases Department, The Second Medical Center of PLA General Hospital, Beijing, 100853 China
| | - Yi Yu
- Respiratory Diseases Department, The Second Medical Center of PLA General Hospital, Beijing, 100853 China
| | - Peng Wang
- Respiratory Diseases Department, The Second Medical Center of PLA General Hospital, Beijing, 100853 China
| | - Diangeng Li
- Respiratory Diseases Department, The Second Medical Center of PLA General Hospital, Beijing, 100853 China
| | - Xian Zhao
- Respiratory Diseases Department, The Second Medical Center of PLA General Hospital, Beijing, 100853 China
| | - Changting Liu
- Respiratory Diseases Department, The Second Medical Center of PLA General Hospital, Beijing, 100853 China
| |
Collapse
|
7
|
Ongoing Transposon-Mediated Genome Reduction in the Luminous Bacterial Symbionts of Deep-Sea Ceratioid Anglerfishes. mBio 2018; 9:mBio.01033-18. [PMID: 29946051 PMCID: PMC6020299 DOI: 10.1128/mbio.01033-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diverse marine fish and squid form symbiotic associations with extracellular bioluminescent bacteria. These symbionts are typically free-living bacteria with large genomes, but one known lineage of symbionts has undergone genomic reduction and evolution of host dependence. It is not known why distinct evolutionary trajectories have occurred among different luminous symbionts, and not all known lineages previously had genome sequences available. In order to better understand patterns of evolution across diverse bioluminescent symbionts, we de novo sequenced the genomes of bacteria from a poorly studied interaction, the extracellular symbionts from the "lures" of deep-sea ceratioid anglerfishes. Deep-sea anglerfish symbiont genomes are reduced in size by about 50% compared to free-living relatives. They show a striking convergence of genome reduction and loss of metabolic capabilities with a distinct lineage of obligately host-dependent luminous symbionts. These losses include reductions in amino acid synthesis pathways and abilities to utilize diverse sugars. However, the symbiont genomes have retained a number of categories of genes predicted to be useful only outside the host, such as those involved in chemotaxis and motility, suggesting that they may persist in the environment. These genomes contain very high numbers of pseudogenes and show massive expansions of transposable elements, with transposases accounting for 28 and 31% of coding sequences in the symbiont genomes. Transposon expansions appear to have occurred at different times in each symbiont lineage, indicating either independent evolutions of reduction or symbiont replacement. These results suggest ongoing genomic reduction in extracellular luminous symbionts that is facilitated by transposon proliferations.IMPORTANCE Many female deep-sea anglerfishes possess a "lure" containing luminous bacterial symbionts. Here we show that unlike most luminous symbionts, these bacteria are undergoing an evolutionary transition toward small genomes with limited metabolic capabilities. Comparative analyses of the symbiont genomes indicate that this transition is ongoing and facilitated by transposon expansions. This transition may have occurred independently in different symbiont lineages, although it is unclear why. Genomic reduction is common in bacteria that only live within host cells but less common in bacteria that, like anglerfish symbionts, live outside host cells. Since multiple evolutions of genomic reduction have occurred convergently in luminous bacteria, they make a useful system with which to understand patterns of genome evolution in extracellular symbionts. This work demonstrates that ecological factors other than an intracellular lifestyle can lead to dramatic gene loss and evolutionary changes and that transposon expansions may play important roles in this process.
Collapse
|
8
|
Kumru S, Tekedar HC, Gulsoy N, Waldbieser GC, Lawrence ML, Karsi A. Comparative Analysis of the Flavobacterium columnare Genomovar I and II Genomes. Front Microbiol 2017; 8:1375. [PMID: 28790987 PMCID: PMC5524665 DOI: 10.3389/fmicb.2017.01375] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 07/06/2017] [Indexed: 11/16/2022] Open
Abstract
Columnaris disease caused by Gram-negative rod Flavobacterium columnare is one of the most common diseases of catfish. F. columnare is also a common problem in other cultured fish species worldwide. F. columnare has three major genomovars; we have sequenced a representative strain from genomovar I (ATCC 49512, which is avirulent in catfish) and genomovar II (94-081, which is highly pathogenic in catfish). Here, we present a comparative analysis of the two genomes. Interestingly, F. columnare ATCC 49512 and 94-081 meet criteria to be considered different species based on the Average Nucleotide Identity (90.71% similar) and DNA–DNA Hybridization (42.6% similar). Genome alignment indicated the two genomes have a large number of rearrangements. However, function-based comparative genomics analysis indicated that the two strains have similar functional capabilities with 2,263 conserved orthologous clusters; strain ATCC 49512 has 290 unique orthologous clusters while strain 94-081 has 391. Both strains carry type I secretion system, type VI secretion system, and type IX secretion system. The two genomes also have similar CRISPR capacities. The F. columnare strain ATCC 49512 genome contains a higher number of insertion sequence families and phage regions, while the F. columnare strain 94-081 genome has more genomic islands and more regulatory gene capacity. Transposon mutagenesis using Tn4351 in pathogenic strain 94-081 yielded six mutants, and experimental infections of fish showed hemolysin and glycine cleavage protein mutants had 15 and 10% mortalities, respectively, while the wild-type strain caused 100% mortalities. Our comparative and mutational analysis yielded important information on classification of genomovars I and II F. columnare as well as potential virulence genes in F. columnare strain 94-081.
Collapse
Affiliation(s)
- Salih Kumru
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State UniversityMississippi State, MS, United States
| | - Hasan C Tekedar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State UniversityMississippi State, MS, United States
| | - Nagihan Gulsoy
- Department of Biology, Faculty of Art and Sciences, Marmara UniversityIstanbul, Turkey
| | - Geoffrey C Waldbieser
- Warmwater Aquaculture Research Unit, United States Agricultural Research Service, StonevilleMS, United States
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State UniversityMississippi State, MS, United States
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State UniversityMississippi State, MS, United States
| |
Collapse
|
9
|
Cerveau N, Gilbert C, Liu C, Garrett RA, Grève P, Bouchon D, Cordaux R. Genomic context drives transcription of insertion sequences in the bacterial endosymbiont Wolbachia wVulC. Gene 2015; 564:81-6. [PMID: 25813874 DOI: 10.1016/j.gene.2015.03.044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 03/19/2015] [Accepted: 03/20/2015] [Indexed: 11/24/2022]
Abstract
Transposable elements (TEs) are DNA pieces that are present in almost all the living world at variable genomic density. Due to their mobility and density, TEs are involved in a large array of genomic modifications. In eukaryotes, TE expression has been studied in detail in several species. In prokaryotes, studies of IS expression are generally linked to particular copies that induce a modification of neighboring gene expression. Here we investigated global patterns of IS transcription in the Alphaproteobacterial endosymbiont Wolbachia wVulC, using both RT-PCR and bioinformatic analyses. We detected several transcriptional promoters in all IS groups. Nevertheless, only one of the potentially functional IS groups possesses a promoter located upstream of the transposase gene, that could lead up to the production of a functional protein. We found that the majority of IS groups are expressed whatever their functional status. RT-PCR analyses indicate that the transcription of two IS groups lacking internal promoters upstream of the transposase start codon may be driven by the genomic environment. We confirmed this observation with the transcription analysis of individual copies of one IS group. These results suggest that the genomic environment is important for IS expression and it could explain, at least partly, copy number variability of the various IS groups present in the wVulC genome and, more generally, in bacterial genomes.
Collapse
Affiliation(s)
- Nicolas Cerveau
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, 5 Rue Albert Turpin, 86073 Poitiers Cedex 9, France
| | - Clément Gilbert
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, 5 Rue Albert Turpin, 86073 Poitiers Cedex 9, France
| | - Chao Liu
- Department of Biology, University of Copenhagen, 2200N Copenhagen, Denmark
| | - Roger A Garrett
- Department of Biology, University of Copenhagen, 2200N Copenhagen, Denmark
| | - Pierre Grève
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, 5 Rue Albert Turpin, 86073 Poitiers Cedex 9, France
| | - Didier Bouchon
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, 5 Rue Albert Turpin, 86073 Poitiers Cedex 9, France
| | - Richard Cordaux
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, 5 Rue Albert Turpin, 86073 Poitiers Cedex 9, France.
| |
Collapse
|
10
|
Pagnier I, Yutin N, Croce O, Makarova KS, Wolf YI, Benamar S, Raoult D, Koonin EV, La Scola B. Babela massiliensis, a representative of a widespread bacterial phylum with unusual adaptations to parasitism in amoebae. Biol Direct 2015; 10:13. [PMID: 25884386 PMCID: PMC4378268 DOI: 10.1186/s13062-015-0043-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/12/2015] [Indexed: 11/24/2022] Open
Abstract
Background Only a small fraction of bacteria and archaea that are identifiable by metagenomics can be grown on standard media. Recent efforts on deep metagenomics sequencing, single-cell genomics and the use of specialized culture conditions (culturomics) increasingly yield novel microbes some of which represent previously uncharacterized phyla and possess unusual biological traits. Results We report isolation and genome analysis of Babela massiliensis, an obligate intracellular parasite of Acanthamoeba castellanii. B. massiliensis shows an unusual, fission mode of cell multiplication whereby large, polymorphic bodies accumulate in the cytoplasm of infected amoeba and then split into mature bacterial cells. This unique mechanism of cell division is associated with a deep degradation of the cell division machinery and delayed expression of the ftsZ gene. The genome of B. massiliensis consists of a circular chromosome approximately 1.12 megabase in size that encodes, 981 predicted proteins, 38 tRNAs and one typical rRNA operon. Phylogenetic analysis shows that B. massiliensis belongs to the putative bacterial phylum TM6 that so far was represented by the draft genome of the JCVI TM6SC1 bacterium obtained by single cell genomics and numerous environmental sequences. Conclusions Currently, B. massiliensis is the only cultivated member of the putative TM6 phylum. Phylogenomic analysis shows diverse taxonomic affinities for B. massiliensis genes, suggestive of multiple gene acquisitions via horizontal transfer from other bacteria and eukaryotes. Horizontal gene transfer is likely to be facilitated by the cohabitation of diverse parasites and symbionts inside amoeba. B. massiliensis encompasses many genes encoding proteins implicated in parasite-host interaction including the greatest number of ankyrin repeats among sequenced bacteria and diverse proteins related to the ubiquitin system. Characterization of B. massiliensis, a representative of a distinct bacterial phylum, thanks to its ability to grow in amoeba, reaffirms the critical role of diverse culture approaches in microbiology. Reviewers This article was reviewed by Dr. Igor Zhulin, Dr. Jeremy Selengut, and Pr Martijn Huynen. Electronic supplementary material The online version of this article (doi:10.1186/s13062-015-0043-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Isabelle Pagnier
- URMITE, CNRS UMR IRD 6236, Faculté de Médecine, Université de la Méditerranée, 27 Bd. Jean Moulin, 13385, Marseille Cedex 5, France.
| | - Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA.
| | - Olivier Croce
- URMITE, CNRS UMR IRD 6236, Faculté de Médecine, Université de la Méditerranée, 27 Bd. Jean Moulin, 13385, Marseille Cedex 5, France.
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA.
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA.
| | - Samia Benamar
- URMITE, CNRS UMR IRD 6236, Faculté de Médecine, Université de la Méditerranée, 27 Bd. Jean Moulin, 13385, Marseille Cedex 5, France.
| | - Didier Raoult
- URMITE, CNRS UMR IRD 6236, Faculté de Médecine, Université de la Méditerranée, 27 Bd. Jean Moulin, 13385, Marseille Cedex 5, France.
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA.
| | - Bernard La Scola
- URMITE, CNRS UMR IRD 6236, Faculté de Médecine, Université de la Méditerranée, 27 Bd. Jean Moulin, 13385, Marseille Cedex 5, France.
| |
Collapse
|
11
|
Steffen MM, Dearth SP, Dill BD, Li Z, Larsen KM, Campagna SR, Wilhelm SW. Nutrients drive transcriptional changes that maintain metabolic homeostasis but alter genome architecture in Microcystis. THE ISME JOURNAL 2014; 8:2080-92. [PMID: 24858783 PMCID: PMC4184021 DOI: 10.1038/ismej.2014.78] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 04/02/2014] [Accepted: 04/08/2014] [Indexed: 11/09/2022]
Abstract
The cyanobacterium Microcystis aeruginosa is a globally distributed bloom-forming organism that degrades freshwater systems around the world. Factors that drive its dispersion, diversification and success remain, however, poorly understood. To develop insight into cellular-level responses to nutrient drivers of eutrophication, RNA sequencing was coupled to a comprehensive metabolomics survey of M. aeruginosa sp. NIES 843 grown in various nutrient-reduced conditions. Transcriptomes were generated for cultures grown in nutrient-replete (with nitrate as the nitrogen (N) source), nitrogen-reduced (with nitrate, urea or ammonium acting as the N sources) and phosphate-reduced conditions. Extensive expression differences (up to 696 genes for urea-grown cells) relative to the control treatment were observed, demonstrating that the chemical variant of nitrogen available to cells affected transcriptional activity. Of particular note, a high number of transposase genes (up to 81) were significantly and reproducibly up-regulated relative to the control when grown on urea. Conversely, phosphorus (P) reduction resulted in a significant cessation in transcription of transposase genes, indicating that variation in nutrient chemistry may influence transcription of transposases and may impact the highly mosaic genomic architecture of M. aeruginosa. Corresponding metabolomes showed comparably few differences between treatments, suggesting broad changes to gene transcription are required to maintain metabolic homeostasis under nutrient reduction. The combined observations provide novel and extensive insight into the complex cellular interactions that take place in this important bloom-forming organism during variable nutrient conditions and highlight a potential unknown molecular mechanism that may drive Microcystis blooms and evolution.
Collapse
Affiliation(s)
- Morgan M Steffen
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Stephen P Dearth
- Department of Chemistry, University of Tennessee, Knoxville, TN, USA
| | - Brian D Dill
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Zhou Li
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, USA
| | - Kristen M Larsen
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Shawn R Campagna
- Department of Chemistry, University of Tennessee, Knoxville, TN, USA
| | - Steven W Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| |
Collapse
|
12
|
Santos-Garcia D, Rollat-Farnier PA, Beitia F, Zchori-Fein E, Vavre F, Mouton L, Moya A, Latorre A, Silva FJ. The genome of Cardinium cBtQ1 provides insights into genome reduction, symbiont motility, and its settlement in Bemisia tabaci. Genome Biol Evol 2014; 6:1013-30. [PMID: 24723729 PMCID: PMC4007549 DOI: 10.1093/gbe/evu077] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Many insects harbor inherited bacterial endosymbionts. Although some of them are not strictly essential and are considered facultative, they can be a key to host survival under specific environmental conditions, such as parasitoid attacks, climate changes, or insecticide pressures. The whitefly Bemisia tabaci is at the top of the list of organisms inflicting agricultural damage and outbreaks, and changes in its distribution may be associated to global warming. In this work, we have sequenced and analyzed the genome of Cardinium cBtQ1, a facultative bacterial endosymbiont of B. tabaci and propose that it belongs to a new taxonomic family, which also includes Candidatus Amoebophilus asiaticus and Cardinium cEper1, endosymbionts of amoeba and wasps, respectively. Reconstruction of their last common ancestors' gene contents revealed an initial massive gene loss from the free-living ancestor. This was followed in Cardinium by smaller losses, associated with settlement in arthropods. Some of these losses, affecting cofactor and amino acid biosynthetic encoding genes, took place in Cardinium cBtQ1 after its divergence from the Cardinium cEper1 lineage and were related to its settlement in the whitefly and its endosymbionts. Furthermore, the Cardinium cBtQ1 genome displays a large proportion of transposable elements, which have recently inactivated genes and produced chromosomal rearrangements. The genome also contains a chromosomal duplication and a multicopy plasmid, which harbors several genes putatively associated with gliding motility, as well as two other genes encoding proteins with potential insecticidal activity. As gene amplification is very rare in endosymbionts, an important function of these genes cannot be ruled out.
Collapse
Affiliation(s)
- Diego Santos-Garcia
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
| | - Pierre-Antoine Rollat-Farnier
- Université de Lyon, Université Lyon1, Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Villeurbanne, France
- BAMBOO Research team, INRIA Grenoble, Rhône-Alpes, France
| | - Francisco Beitia
- Instituto Valenciano de Investigaciones Agrarias, Unidad Asociada de Entomología IVIA/CIB-CSIC, Valencia, Spain
| | - Einat Zchori-Fein
- Department of Entomology, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, Israel
| | - Fabrice Vavre
- Université de Lyon, Université Lyon1, Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Villeurbanne, France
- BAMBOO Research team, INRIA Grenoble, Rhône-Alpes, France
| | - Laurence Mouton
- Université de Lyon, Université Lyon1, Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Villeurbanne, France
| | - Andrés Moya
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Valencia, Spain
| | - Amparo Latorre
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Valencia, Spain
- *Corresponding author: E-mail: ;
| | - Francisco J. Silva
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Unidad Mixta de Investigación en Genómica y Salud (FISABIO-Salud Pública and Universitat de València), Valencia, Spain
- *Corresponding author: E-mail: ;
| |
Collapse
|
13
|
Siguier P, Gourbeyre E, Chandler M. Bacterial insertion sequences: their genomic impact and diversity. FEMS Microbiol Rev 2014; 38:865-91. [PMID: 24499397 PMCID: PMC7190074 DOI: 10.1111/1574-6976.12067] [Citation(s) in RCA: 387] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/19/2014] [Accepted: 01/22/2014] [Indexed: 01/06/2023] Open
Abstract
Insertion sequences (ISs), arguably the smallest and most numerous autonomous transposable elements (TEs), are important players in shaping their host genomes. This review focuses on prokaryotic ISs. We discuss IS distribution and impact on genome evolution. We also examine their effects on gene expression, especially their role in activating neighbouring genes, a phenomenon of particular importance in the recent upsurge of bacterial antibiotic resistance. We explain how ISs are identified and classified into families by a combination of characteristics including their transposases (Tpases), their overall genetic organisation and the accessory genes which some ISs carry. We then describe the organisation of autonomous and nonautonomous IS‐related elements. This is used to illustrate the growing recognition that the boundaries between different types of mobile element are becoming increasingly difficult to define as more are being identified. We review the known Tpase types, their different catalytic activities used in cleaving and rejoining DNA strands during transposition, their organisation into functional domains and the role of this in regulation. Finally, we consider examples of prokaryotic IS domestication. In a more speculative section, we discuss the necessity of constructing more quantitative dynamic models to fully appreciate the continuing impact of TEs on prokaryotic populations.
Collapse
Affiliation(s)
- Patricia Siguier
- Laboratoire de Microbiologie et Génétique Moléculaires, Unité Mixte de Recherche 5100, Centre National de Recherche Scientifique, Toulouse Cedex, France
| | | | | |
Collapse
|
14
|
Martínez-Cano DJ, Reyes-Prieto M, Martínez-Romero E, Partida-Martínez LP, Latorre A, Moya A, Delaye L. Evolution of small prokaryotic genomes. Front Microbiol 2014; 5:742. [PMID: 25610432 PMCID: PMC4285135 DOI: 10.3389/fmicb.2014.00742] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/07/2014] [Indexed: 02/05/2023] Open
Abstract
As revealed by genome sequencing, the biology of prokaryotes with reduced genomes is strikingly diverse. These include free-living prokaryotes with ∼800 genes as well as endosymbiotic bacteria with as few as ∼140 genes. Comparative genomics is revealing the evolutionary mechanisms that led to these small genomes. In the case of free-living prokaryotes, natural selection directly favored genome reduction, while in the case of endosymbiotic prokaryotes neutral processes played a more prominent role. However, new experimental data suggest that selective processes may be at operation as well for endosymbiotic prokaryotes at least during the first stages of genome reduction. Endosymbiotic prokaryotes have evolved diverse strategies for living with reduced gene sets inside a host-defined medium. These include utilization of host-encoded functions (some of them coded by genes acquired by gene transfer from the endosymbiont and/or other bacteria); metabolic complementation between co-symbionts; and forming consortiums with other bacteria within the host. Recent genome sequencing projects of intracellular mutualistic bacteria showed that previously believed universal evolutionary trends like reduced G+C content and conservation of genome synteny are not always present in highly reduced genomes. Finally, the simplified molecular machinery of some of these organisms with small genomes may be used to aid in the design of artificial minimal cells. Here we review recent genomic discoveries of the biology of prokaryotes endowed with small gene sets and discuss the evolutionary mechanisms that have been proposed to explain their peculiar nature.
Collapse
Affiliation(s)
| | - Mariana Reyes-Prieto
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de ValenciaValencia, Spain
| | | | | | - Amparo Latorre
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de ValenciaValencia, Spain
| | - Andrés Moya
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de ValenciaValencia, Spain
| | - Luis Delaye
- Departamento de Ingeniería Genética, Cinvestav Unidad IrapuatoIrapuato, Mexico
- *Correspondence: Luis Delaye, Departamento de Ingeniería Genética, Cinvestav Unidad Irapuato, Kilometer 9.6, Libramiento Norte, Carretera Irapuato-León, Irapuato, Guanajuato 36821, Mexico e-mail:
| |
Collapse
|
15
|
Oakeson KF, Gil R, Clayton AL, Dunn DM, von Niederhausern AC, Hamil C, Aoyagi A, Duval B, Baca A, Silva FJ, Vallier A, Jackson DG, Latorre A, Weiss RB, Heddi A, Moya A, Dale C. Genome degeneration and adaptation in a nascent stage of symbiosis. Genome Biol Evol 2014; 6:76-93. [PMID: 24407854 PMCID: PMC3914690 DOI: 10.1093/gbe/evt210] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Symbiotic associations between animals and microbes are ubiquitous in nature, with an estimated 15% of all insect species harboring intracellular bacterial symbionts. Most bacterial symbionts share many genomic features including small genomes, nucleotide composition bias, high coding density, and a paucity of mobile DNA, consistent with long-term host association. In this study, we focus on the early stages of genome degeneration in a recently derived insect-bacterial mutualistic intracellular association. We present the complete genome sequence and annotation of Sitophilus oryzae primary endosymbiont (SOPE). We also present the finished genome sequence and annotation of strain HS, a close free-living relative of SOPE and other insect symbionts of the Sodalis-allied clade, whose gene inventory is expected to closely resemble the putative ancestor of this group. Structural, functional, and evolutionary analyses indicate that SOPE has undergone extensive adaptation toward an insect-associated lifestyle in a very short time period. The genome of SOPE is large in size when compared with many ancient bacterial symbionts; however, almost half of the protein-coding genes in SOPE are pseudogenes. There is also evidence for relaxed selection on the remaining intact protein-coding genes. Comparative analyses of the whole-genome sequence of strain HS and SOPE highlight numerous genomic rearrangements, duplications, and deletions facilitated by a recent expansion of insertions sequence elements, some of which appear to have catalyzed adaptive changes. Functional metabolic predictions suggest that SOPE has lost the ability to synthesize several essential amino acids and vitamins. Analyses of the bacterial cell envelope and genes encoding secretion systems suggest that these structures and elements have become simplified in the transition to a mutualistic association.
Collapse
Affiliation(s)
- Kelly F. Oakeson
- Department of Biology, University of Utah
- *Corresponding author: E-mail:
| | - Rosario Gil
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
| | | | | | | | - Cindy Hamil
- Department of Human Genetics, University of Utah
| | - Alex Aoyagi
- Department of Human Genetics, University of Utah
| | - Brett Duval
- Department of Human Genetics, University of Utah
| | | | - Francisco J. Silva
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
| | - Agnès Vallier
- INSA-Lyon, INRA, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Villeurbanne, France
| | | | - Amparo Latorre
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Área de Genómica y Salud, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana FISABIO – Salud Pública, Valencia, Spain
| | | | - Abdelaziz Heddi
- INSA-Lyon, INRA, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Villeurbanne, France
| | - Andrés Moya
- Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Spain
- Área de Genómica y Salud, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana FISABIO – Salud Pública, Valencia, Spain
| | - Colin Dale
- Department of Biology, University of Utah
| |
Collapse
|
16
|
Abstract
Transposases, enzymes that catalyze the movement of mobile genetic elements, are the most abundant genes in nature. While many bacteria encode an abundance of transposases in their genomes, the current paradigm is that the expression of transposase genes is tightly regulated and generally low due to its severe mutagenic effects. In the current study, we detected the highest number of transposase proteins ever reported in bacteria, in symbionts of the gutless marine worm Olavius algarvensis with metaproteomics. At least 26 different transposases from 12 different families were detected, and genomic and proteomic analyses suggest that many of these are active. This high expression of transposases indicates that the mechanisms for their tight regulation have been disabled or no longer exist.
Collapse
|
17
|
Lateral transfers of insertion sequences between Wolbachia, Cardinium and Rickettsia bacterial endosymbionts. Heredity (Edinb) 2013; 111:330-7. [PMID: 23759724 DOI: 10.1038/hdy.2013.56] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/13/2013] [Accepted: 05/13/2013] [Indexed: 11/09/2022] Open
Abstract
Various bacteria live exclusively within arthropod cells and collectively act as an important driver of arthropod evolutionary ecology. Whereas rampant intra-generic DNA transfers were recently shown to have a pivotal role in the evolution of the most common of these endosymbionts, Wolbachia, the present study show that inter-generic DNA transfers also commonly take place, constituting a potent source of rapid genomic change. Bioinformatic, molecular and phylogenetic data provide evidence that a selfish genetic element, the insertion sequence ISRpe1, is widespread in the Wolbachia, Cardinium and Rickettsia endosymbionts and experiences recent (and likely ongoing) transfers over long evolutionary distances. Although many ISRpe1 copies were clearly expanding and leading to rapid endosymbiont diversification, degraded copies are also frequently found, constituting an unusual genomic fossil record suggestive of ancient ISRpe1 expansions. Overall, the present data highlight how ecological connections within the arthropod intracellular environment facilitate lateral DNA transfers between distantly related bacterial lineages.
Collapse
|
18
|
TnpPred: A Web Service for the Robust Prediction of Prokaryotic Transposases. Comp Funct Genomics 2012; 2012:678761. [PMID: 23251097 PMCID: PMC3506888 DOI: 10.1155/2012/678761] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 08/20/2012] [Accepted: 09/18/2012] [Indexed: 11/18/2022] Open
Abstract
Transposases (Tnps) are enzymes that participate in the movement of insertion sequences (ISs) within and between genomes. Genes
that encode Tnps are amongst the most abundant and widely distributed genes in nature. However, they are difficult to
predict bioinformatically and given the increasing availability of prokaryotic genomes and metagenomes, it is incumbent to develop
rapid, high quality automatic annotation of ISs. This need prompted us to develop a web service, termed TnpPred for Tnp
discovery. It provides better sensitivity and specificity for Tnp predictions than given by currently available programs as
determined by ROC analysis. TnpPred should be useful for improving genome annotation. The TnpPred web service is freely available for
noncommercial use.
Collapse
|
19
|
Comparative genomics suggests an independent origin of cytoplasmic incompatibility in Cardinium hertigii. PLoS Genet 2012; 8:e1003012. [PMID: 23133394 PMCID: PMC3486910 DOI: 10.1371/journal.pgen.1003012] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 08/22/2012] [Indexed: 11/28/2022] Open
Abstract
Terrestrial arthropods are commonly infected with maternally inherited bacterial symbionts that cause cytoplasmic incompatibility (CI). In CI, the outcome of crosses between symbiont-infected males and uninfected females is reproductive failure, increasing the relative fitness of infected females and leading to spread of the symbiont in the host population. CI symbionts have profound impacts on host genetic structure and ecology and may lead to speciation and the rapid evolution of sex determination systems. Cardinium hertigii, a member of the Bacteroidetes and symbiont of the parasitic wasp Encarsia pergandiella, is the only known bacterium other than the Alphaproteobacteria Wolbachia to cause CI. Here we report the genome sequence of Cardinium hertigii cEper1. Comparison with the genomes of CI–inducing Wolbachia pipientis strains wMel, wRi, and wPip provides a unique opportunity to pinpoint shared proteins mediating host cell interaction, including some candidate proteins for CI that have not previously been investigated. The genome of Cardinium lacks all major biosynthetic pathways but harbors a complete biotin biosynthesis pathway, suggesting a potential role for Cardinium in host nutrition. Cardinium lacks known protein secretion systems but encodes a putative phage-derived secretion system distantly related to the antifeeding prophage of the entomopathogen Serratia entomophila. Lastly, while Cardinium and Wolbachia genomes show only a functional overlap of proteins, they show no evidence of laterally transferred elements that would suggest common ancestry of CI in both lineages. Instead, comparative genomics suggests an independent evolution of CI in Cardinium and Wolbachia and provides a novel context for understanding the mechanistic basis of CI. Many arthropods are infected with bacterial symbionts that are maternally transmitted and have a great impact on their hosts' biology, ecology, and evolution. One of the most common phenotypes of facultative symbionts appears to be cytoplasmic incompatibility (CI), a type of reproductive failure in which bacteria in males modify sperm in a way that reduces the reproductive success of uninfected female mates. In spite of considerable interest, the genetic basis for CI is largely unknown. Cardinium hertigii, a symbiont of tiny parasitic wasps, is the only bacterial group other than the well-studied Wolbachia that is known to cause CI. Analysis of the Cardinium genome indicates that CI evolved independently in Wolbachia and Cardinium. However, a suite of shared proteins was likely involved in mediating host cell interactions, and CI shows functional overlap in both lineages. Our analysis suggests the presence of an unusual phage-derived, putative secretion system and reveals that Cardinium encodes biosynthetic pathways that suggest a potential role in host nutrition. Our findings provide a novel comparative context for understanding the mechanistic basis of CI and substantially increase our knowledge on reproductive manipulator symbionts that do not only severely affect population genetic structure of arthropods but may also serve as powerful tools in pest management.
Collapse
|
20
|
Mappley LJ, Black ML, AbuOun M, Darby AC, Woodward MJ, Parkhill J, Turner AK, Bellgard MI, La T, Phillips ND, La Ragione RM, Hampson DJ. Comparative genomics of Brachyspira pilosicoli strains: genome rearrangements, reductions and correlation of genetic compliment with phenotypic diversity. BMC Genomics 2012; 13:454. [PMID: 22947175 PMCID: PMC3532143 DOI: 10.1186/1471-2164-13-454] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 08/22/2012] [Indexed: 11/12/2022] Open
Abstract
Background The anaerobic spirochaete Brachyspira pilosicoli causes enteric disease in avian, porcine and human hosts, amongst others. To date, the only available genome sequence of B. pilosicoli is that of strain 95/1000, a porcine isolate. In the first intra-species genome comparison within the Brachyspira genus, we report the whole genome sequence of B. pilosicoli B2904, an avian isolate, the incomplete genome sequence of B. pilosicoli WesB, a human isolate, and the comparisons with B. pilosicoli 95/1000. We also draw on incomplete genome sequences from three other Brachyspira species. Finally we report the first application of the high-throughput Biolog phenotype screening tool on the B. pilosicoli strains for detailed comparisons between genotype and phenotype. Results Feature and sequence genome comparisons revealed a high degree of similarity between the three B. pilosicoli strains, although the genomes of B2904 and WesB were larger than that of 95/1000 (~2,765, 2.890 and 2.596 Mb, respectively). Genome rearrangements were observed which correlated largely with the positions of mobile genetic elements. Through comparison of the B2904 and WesB genomes with the 95/1000 genome, features that we propose are non-essential due to their absence from 95/1000 include a peptidase, glycine reductase complex components and transposases. Novel bacteriophages were detected in the newly-sequenced genomes, which appeared to have involvement in intra- and inter-species horizontal gene transfer. Phenotypic differences predicted from genome analysis, such as the lack of genes for glucuronate catabolism in 95/1000, were confirmed by phenotyping. Conclusions The availability of multiple B. pilosicoli genome sequences has allowed us to demonstrate the substantial genomic variation that exists between these strains, and provides an insight into genetic events that are shaping the species. In addition, phenotype screening allowed determination of how genotypic differences translated to phenotype. Further application of such comparisons will improve understanding of the metabolic capabilities of Brachyspira species.
Collapse
Affiliation(s)
- Luke J Mappley
- Department of Bacteriology, Animal Health and Veterinary Laboratories Agency, Reading University, Addlestone, Surrey, UK.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|