1
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Wu LY, Piedade GJ, Moore RM, Harrison AO, Martins AM, Bidle KD, Polson SW, Sakowski EG, Nissimov JI, Dums JT, Ferrell BD, Wommack KE. Ubiquitous, B 12-dependent virioplankton utilizing ribonucleotide-triphosphate reductase demonstrate interseasonal dynamics and associate with a diverse range of bacterial hosts in the pelagic ocean. ISME COMMUNICATIONS 2023; 3:108. [PMID: 37789093 PMCID: PMC10547690 DOI: 10.1038/s43705-023-00306-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 10/05/2023]
Abstract
Through infection and lysis of their coexisting bacterial hosts, viruses impact the biogeochemical cycles sustaining globally significant pelagic oceanic ecosystems. Currently, little is known of the ecological interactions between lytic viruses and their bacterial hosts underlying these biogeochemical impacts at ecosystem scales. This study focused on populations of lytic viruses carrying the B12-dependent Class II monomeric ribonucleotide reductase (RNR) gene, ribonucleotide-triphosphate reductase (Class II RTPR), documenting seasonal changes in pelagic virioplankton and bacterioplankton using amplicon sequences of Class II RTPR and the 16S rRNA gene, respectively. Amplicon sequence libraries were analyzed using compositional data analysis tools that account for the compositional nature of these data. Both virio- and bacterioplankton communities responded to environmental changes typically seen across seasonal cycles as well as shorter term upwelling-downwelling events. Defining Class II RTPR-carrying viral populations according to major phylogenetic clades proved a more robust means of exploring virioplankton ecology than operational taxonomic units defined by percent sequence homology. Virioplankton Class II RTPR populations showed positive associations with a broad phylogenetic diversity of bacterioplankton including dominant taxa within pelagic oceanic ecosystems such as Prochlorococcus and SAR11. Temporal changes in Class II RTPR virioplankton, occurring as both free viruses and within infected cells, indicated possible viral-host pairs undergoing sustained infection and lysis cycles throughout the seasonal study. Phylogenetic relationships inferred from Class II RTPR sequences mirrored ecological patterns in virio- and bacterioplankton populations demonstrating possible genome to phenome associations for an essential viral replication gene.
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Affiliation(s)
- Ling-Yi Wu
- Theoretical Biology and Bioinformatics, Science4Life, Utrecht University, Padualaan 8, Utrecht, 3584 CH, the Netherlands
| | - Gonçalo J Piedade
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, 1797 SZ, t'Horntje, The Netherlands
- Department of Oceanography and Fisheries and Ocean Sciences Institute-OKEANOS, University of the Azores, 9901-862 Horta, Faial, Azores, Portugal
| | - Ryan M Moore
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
| | - Amelia O Harrison
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
| | - Ana M Martins
- Department of Oceanography and Fisheries and Ocean Sciences Institute-OKEANOS, University of the Azores, 9901-862 Horta, Faial, Azores, Portugal
| | - Kay D Bidle
- Department of Marine and Coastal Sciences, Rutgers University, 71 Dudley Rd., New Brunswick, NJ, 08901, USA
| | - Shawn W Polson
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
| | - Eric G Sakowski
- Department of Earth Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Jozef I Nissimov
- Department of Biology, University of Waterloo, 200 University Ave. West, Waterloo, ON, N2L 3G1, Canada
| | - Jacob T Dums
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
- Biotechnology Program, North Carolina State University, 2800 Faucette Dr, Raleigh, NC, 27695, USA
| | - Barbra D Ferrell
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA
| | - K Eric Wommack
- Delaware Biotechnology Institute, University of Delaware, 590 Avenue 1743, Newark, DE, 19713, USA.
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2
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Schwartz DA, Shoemaker WR, Măgălie A, Weitz JS, Lennon JT. Bacteria-phage coevolution with a seed bank. THE ISME JOURNAL 2023:10.1038/s41396-023-01449-2. [PMID: 37286738 DOI: 10.1038/s41396-023-01449-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/25/2023] [Accepted: 05/30/2023] [Indexed: 06/09/2023]
Abstract
Dormancy is an adaptation to living in fluctuating environments. It allows individuals to enter a reversible state of reduced metabolic activity when challenged by unfavorable conditions. Dormancy can also influence species interactions by providing organisms with a refuge from predators and parasites. Here we test the hypothesis that, by generating a seed bank of protected individuals, dormancy can modify the patterns and processes of antagonistic coevolution. We conducted a factorially designed experiment where we passaged a bacterial host (Bacillus subtilis) and its phage (SPO1) in the presence versus absence of a seed bank consisting of dormant endospores. Owing in part to the inability of phages to attach to spores, seed banks stabilized population dynamics and resulted in minimum host densities that were 30-fold higher compared to bacteria that were unable to engage in dormancy. By supplying a refuge to phage-sensitive strains, we show that seed banks retained phenotypic diversity that was otherwise lost to selection. Dormancy also stored genetic diversity. After characterizing allelic variation with pooled population sequencing, we found that seed banks retained twice as many host genes with mutations, whether phages were present or not. Based on mutational trajectories over the course of the experiment, we demonstrate that seed banks can dampen bacteria-phage coevolution. Not only does dormancy create structure and memory that buffers populations against environmental fluctuations, it also modifies species interactions in ways that can feed back onto the eco-evolutionary dynamics of microbial communities.
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Affiliation(s)
- Daniel A Schwartz
- Department of Biology, Indiana University, Bloomington, Indiana, IN, USA
| | - William R Shoemaker
- The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy
| | - Andreea Măgălie
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Interdisciplinary Graduate Program in Quantitative Biosciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Joshua S Weitz
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
- Institut de Biologie, École Normale Supérieure, Paris, France
| | - Jay T Lennon
- Department of Biology, Indiana University, Bloomington, Indiana, IN, USA.
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3
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Shaer Tamar E, Kishony R. Multistep diversification in spatiotemporal bacterial-phage coevolution. Nat Commun 2022; 13:7971. [PMID: 36577749 PMCID: PMC9797572 DOI: 10.1038/s41467-022-35351-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 11/29/2022] [Indexed: 12/29/2022] Open
Abstract
The evolutionary arms race between phages and bacteria, where bacteria evolve resistance to phages and phages retaliate with resistance-countering mutations, is a major driving force of molecular innovation and genetic diversification. Yet attempting to reproduce such ongoing retaliation dynamics in the lab has been challenging; laboratory coevolution experiments of phage and bacteria are typically performed in well-mixed environments and often lead to rapid stagnation with little genetic variability. Here, co-culturing motile E. coli with the lytic bacteriophage T7 on swimming plates, we observe complex spatiotemporal dynamics with multiple genetically diversifying adaptive cycles. Systematically quantifying over 10,000 resistance-infectivity phenotypes between evolved bacteria and phage isolates, we observe diversification into multiple coexisting ecotypes showing a complex interaction network with both host-range expansion and host-switch tradeoffs. Whole-genome sequencing of these evolved phage and bacterial isolates revealed a rich set of adaptive mutations in multiple genetic pathways including in genes not previously linked with phage-bacteria interactions. Synthetically reconstructing these new mutations, we discover phage-general and phage-specific resistance phenotypes as well as a strong synergy with the more classically known phage-resistance mutations. These results highlight the importance of spatial structure and migration for driving phage-bacteria coevolution, providing a concrete system for revealing new molecular mechanisms across diverse phage-bacterial systems.
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Affiliation(s)
- Einat Shaer Tamar
- grid.6451.60000000121102151Faculty of Biology, Technion–Israel Institute of Technology, Haifa, Israel
| | - Roy Kishony
- grid.6451.60000000121102151Faculty of Biology, Technion–Israel Institute of Technology, Haifa, Israel ,grid.6451.60000000121102151Faculty of Computer Science, Technion–Israel Institute of Technology, Haifa, Israel ,grid.6451.60000000121102151Faculty of Biomedical Engineering, Technion–Israel Institute of Technology, Haifa, Israel
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4
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Maidanik I, Kirzner S, Pekarski I, Arsenieff L, Tahan R, Carlson MCG, Shitrit D, Baran N, Goldin S, Weitz JS, Lindell D. Cyanophages from a less virulent clade dominate over their sister clade in global oceans. THE ISME JOURNAL 2022; 16:2169-2180. [PMID: 35726021 PMCID: PMC9381782 DOI: 10.1038/s41396-022-01259-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 05/23/2022] [Accepted: 05/27/2022] [Indexed: 11/18/2022]
Abstract
Environmental virus communities are highly diverse. However, the infection physiology underlying the evolution of diverse phage lineages and their ecological consequences are largely unknown. T7-like cyanophages are abundant in nature and infect the marine unicellular cyanobacteria, Synechococcus and Prochlorococcus, important primary producers in the oceans. Viruses belonging to this genus are divided into two distinct phylogenetic clades: clade A and clade B. These viruses have narrow host-ranges with clade A phages primarily infecting Synechococcus genotypes, while clade B phages are more diverse and can infect either Synechococcus or Prochlorococcus genotypes. Here we investigated infection properties (life history traits) and environmental abundances of these two clades of T7-like cyanophages. We show that clade A cyanophages have more rapid infection dynamics, larger burst sizes and greater virulence than clade B cyanophages. However, clade B cyanophages were at least 10-fold more abundant in all seasons, and infected more cyanobacteria, than clade A cyanophages in the Red Sea. Models predicted that steady-state cyanophage abundances, infection frequency, and virus-induced mortality, peak at intermediate virulence values. Our findings indicate that differences in infection properties are reflected in virus phylogeny at the clade level. They further indicate that infection properties, together with differences in subclade diversity and host repertoire, have important ecological consequences with the less aggressive, more diverse virus clade having greater ecological impacts.
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5
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Koskella B, Hernandez CA, Wheatley RM. Understanding the Impacts of Bacteriophage Viruses: From Laboratory Evolution to Natural Ecosystems. Annu Rev Virol 2022; 9:57-78. [PMID: 35584889 DOI: 10.1146/annurev-virology-091919-075914] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Viruses of bacteriophages (phages) have broad effects on bacterial ecology and evolution in nature that mediate microbial interactions, shape bacterial diversity, and influence nutrient cycling and ecosystem function. The unrelenting impact of phages within the microbial realm is the result, in large part, of their ability to rapidly evolve in response to bacterial host dynamics. The knowledge gained from laboratory systems, typically using pairwise interactions between single-host and single-phage systems, has made clear that phages coevolve with their bacterial hosts rapidly, somewhat predictably, and primarily by counteradapting to host resistance. Recent advancement in metagenomics approaches, as well as a shifting focus toward natural microbial communities and host-associated microbiomes, is beginning to uncover the full picture of phage evolution and ecology within more complex settings. As these data reach their full potential, it will be critical to ask when and how insights gained from studies of phage evolution in vitro can be meaningfully applied to understanding bacteria-phage interactions in nature. In this review, we explore the myriad ways that phages shape and are themselves shaped by bacterial host populations and communities, with a particular focus on observed and predicted differences between the laboratory and complex microbial communities. Expected final online publication date for the Annual Review of Virology, Volume 9 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Britt Koskella
- Department of Integrative Biology, University of California, Berkeley, California, USA;
| | - Catherine A Hernandez
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, USA
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6
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Bujak K, Decewicz P, Kitowicz M, Radlinska M. Characterization of Three Novel Virulent Aeromonas Phages Provides Insights into the Diversity of the Autographiviridae Family. Viruses 2022; 14:1016. [PMID: 35632757 PMCID: PMC9145550 DOI: 10.3390/v14051016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/29/2022] [Accepted: 05/05/2022] [Indexed: 11/17/2022] Open
Abstract
In this study, we isolated and characterized three novel virulent Autographiviridae bacteriophages, vB_AspA_Bolek, vB_AspA_Lolek, and vB_AspA_Tola, which infect different Aeromonas strains. These three host-pathogen pairs were derived from the same sampling location-the arsenic-containing microbial mats of the Zloty Stok gold mine. Functional analysis showed they are psychrotolerant (4-25 °C), albeit with a much wider temperature range of propagation for the hosts (≤37 °C). Comparative genomic analyses revealed a high nucleotide and amino acid sequence similarity of vB_AspA_Bolek and vB_AspA_Lolek, with significant differences exclusively in the C-terminal region of their tail fibers, which might explain their host range discrimination. The protein-based phage network, together with a phylogenetic analysis of the marker proteins, allowed us to assign vB_AspA_Bolek and vB_AspA_Lolek to the Beijerinckvirinae and vB_AspA_Tola to the Colwellvirinae subfamilies, but as three novel species, due to their low nucleotide sequence coverage and identity with other known phage genomes. Global comparative analysis showed that the studied phages are also markedly different from most of the 24 Aeromonas autographiviruses known so far. Finally, this study provides in-depth insight into the diversity of the Autographiviridae phages and reveals genomic similarities between selected groups of this family as well as between autographiviruses and their relatives of other Caudoviricetes families.
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Affiliation(s)
| | | | | | - Monika Radlinska
- Department of Environmental Microbiology and Biotechnology, Faculty of Biology, Institute of Microbiology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland; (K.B.); (P.D.); (M.K.)
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7
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You X, Kallies R, Kühn I, Schmidt M, Harms H, Chatzinotas A, Wick LY. Phage co-transport with hyphal-riding bacteria fuels bacterial invasion in a water-unsaturated microbial model system. THE ISME JOURNAL 2022; 16:1275-1283. [PMID: 34903848 PMCID: PMC9039081 DOI: 10.1038/s41396-021-01155-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 11/09/2022]
Abstract
Nonmotile microorganisms often enter new habitats by co-transport with motile microorganisms. Here, we report that also lytic phages can co-transport with hyphal-riding bacteria and facilitate bacterial colonization of a new habitat. This is comparable to the concept of biological invasions in macroecology. In analogy to invasion frameworks in plant and animal ecology, we tailored spatially organized, water-unsaturated model microcosms using hyphae of Pythium ultimum as invasion paths and flagellated soil-bacterium Pseudomonas putida KT2440 as carrier for co-transport of Escherichia virus T4. P. putida KT2440 efficiently dispersed along P. ultimum to new habitats and dispatched T4 phages across air gaps transporting ≈0.6 phages bacteria−1. No T4 displacement along hyphae was observed in the absence of carrier bacteria. If E. coli occupied the new habitat, T4 co-transport fueled the fitness of invading P. putida KT2440, while the absence of phage co-transport led to poor colonization followed by extinction. Our data emphasize the importance of hyphal transport of bacteria and associated phages in regulating fitness and composition of microbial populations in water-unsaturated systems. As such co-transport seems analogous to macroecological invasion processes, hyphosphere systems with motile bacteria and co-transported phages could be useful models for testing hypotheses in invasion ecology.
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Affiliation(s)
- Xin You
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstr. 15, 04318, Leipzig, Germany
| | - René Kallies
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstr. 15, 04318, Leipzig, Germany
| | - Ingolf Kühn
- Helmholtz Centre for Environmental Research - UFZ, Department of Community Ecology, Theodor-Lieser-Str. 4, 06120, Halle, Germany.,Institute of Biology/Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Halle, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Matthias Schmidt
- Helmholtz Centre for Environmental Research - UFZ, Department of Isotope Biogeochemistry, Permoserstr. 15, 04318, Leipzig, Germany
| | - Hauke Harms
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstr. 15, 04318, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Antonis Chatzinotas
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstr. 15, 04318, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany.,Institute of Biology, Leipzig University, Talstr. 33, Leipzig, 04103, Germany
| | - Lukas Y Wick
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Microbiology, Permoserstr. 15, 04318, Leipzig, Germany.
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8
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Genetic engineering of marine cyanophages reveals integration but not lysogeny in T7-like cyanophages. THE ISME JOURNAL 2022; 16:488-499. [PMID: 34429521 PMCID: PMC8776855 DOI: 10.1038/s41396-021-01085-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 02/07/2023]
Abstract
Marine cyanobacteria of the genera Synechococcus and Prochlorococcus are the most abundant photosynthetic organisms on earth, spanning vast regions of the oceans and contributing significantly to global primary production. Their viruses (cyanophages) greatly influence cyanobacterial ecology and evolution. Although many cyanophage genomes have been sequenced, insight into the functional role of cyanophage genes is limited by the lack of a cyanophage genetic engineering system. Here, we describe a simple, generalizable method for genetic engineering of cyanophages from multiple families, that we named REEP for REcombination, Enrichment and PCR screening. This method enables direct investigation of key cyanophage genes, and its simplicity makes it adaptable to other ecologically relevant host-virus systems. T7-like cyanophages often carry integrase genes and attachment sites, yet exhibit lytic infection dynamics. Here, using REEP, we investigated their ability to integrate and maintain a lysogenic life cycle. We found that these cyanophages integrate into the host genome and that the integrase and attachment site are required for integration. However, stable lysogens did not form. The frequency of integration was found to be low in both lab cultures and the oceans. These findings suggest that T7-like cyanophage integration is transient and is not part of a classical lysogenic cycle.
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9
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Dewald-Wang EA, Parr N, Tiley K, Lee A, Koskella B. Multiyear Time-Shift Study of Bacteria and Phage Dynamics in the Phyllosphere. Am Nat 2022; 199:126-140. [DOI: 10.1086/717181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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10
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Huang S, Sun Y, Zhang S, Long L. Temporal transcriptomes of a marine cyanopodovirus and its Synechococcus host during infection. Microbiologyopen 2020; 10:e1150. [PMID: 33377630 PMCID: PMC7885011 DOI: 10.1002/mbo3.1150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/01/2020] [Accepted: 12/07/2020] [Indexed: 12/24/2022] Open
Abstract
Marine picocyanobacteria belonging to genera Synechococcus and Prochlorococcus are genetically diverged and distributed into distinct biogeographical patterns, and both are infected by genetically closely related cyanopodoviruses. Previous studies have not fully explored whether the two virus–host systems share similar gene expression patterns during infection. Whole‐genome expression dynamics of T7‐like cyanopodovirus P‐SSP7 and its host Prochlorococcus strain MED4 have already been reported. Here, we conducted genomic and transcriptomic analyses on T7‐like cyanopodovirus S‐SBP1 during its infection on Synechococcus strain WH7803. S‐SBP1 has a latent period of 8 h and phage DNA production of 30 copies per cell. In terms of whole‐genome phylogenetic relationships and average nucleotide identity, S‐SBP1 was most similar to cyanopodovirus S‐RIP2, which also infects Synechococcus WH7803. Three hypervariable genomic islands were identified when comparing the genomes of S‐SBP1 and S‐RIP2. Single nucleotide variants were also observed in three S‐SBP1 genes, which were located within the island regions. Based on RNA‐seq analysis, S‐SBP1 genes clustered into three temporal expression classes, whose gene content was similar to that of P‐SSP7. Thirty‐two host genes were upregulated during phage infection, including those involved in carbon metabolism, ribosome components, and stress response. These upregulated genes were similar to those upregulated by Prochlorococcus MED4 in response to infection by P‐SSP7. Our study demonstrates a programmed temporal expression pattern of cyanopodoviruses and hosts during infection.
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Affiliation(s)
- Sijun Huang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Yingting Sun
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Si Zhang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Lijuan Long
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
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11
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Seasonal and diel patterns of abundance and activity of viruses in the Red Sea. Proc Natl Acad Sci U S A 2020; 117:29738-29747. [PMID: 33172994 DOI: 10.1073/pnas.2010783117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Virus-microbe interactions have been studied in great molecular details for many years in cultured model systems, yielding a plethora of knowledge on how viruses use and manipulate host machinery. Since the advent of molecular techniques and high-throughput sequencing, methods such as cooccurrence, nucleotide composition, and other statistical frameworks have been widely used to infer virus-microbe interactions, overcoming the limitations of culturing methods. However, their accuracy and relevance is still debatable as cooccurrence does not necessarily mean interaction. Here we introduce an ecological perspective of marine viral communities and potential interaction with their hosts, using analyses that make no prior assumptions on specific virus-host pairs. By size fractionating water samples into free viruses and microbes (i.e., also viruses inside or attached to their hosts) and looking at how viral group abundance changes over time along both fractions, we show that the viral community is undergoing a change in rank abundance across seasons, suggesting a seasonal succession of viruses in the Red Sea. We use abundance patterns in the different size fractions to classify viral clusters, indicating potential diverse interactions with their hosts and potential differences in life history traits between major viral groups. Finally, we show hourly resolved variations of intracellular abundance of similar viral groups, which might indicate differences in their infection cycles or metabolic capacities.
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12
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crAssphage genomes identified in fecal samples of an adult and infants with evidence of positive genomic selective pressure within tail protein genes. Virus Res 2020; 292:198219. [PMID: 33137401 DOI: 10.1016/j.virusres.2020.198219] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/06/2020] [Accepted: 10/26/2020] [Indexed: 01/21/2023]
Abstract
crAssphages are a broad group of diverse bacteriophages in the order Caudovirales that have been found to be highly abundant in the human gastrointestinal tract. Despite their high prevalence, we have an incomplete understanding of how crAssphages shape and respond to ecological and evolutionary dynamics in the gut. Here, we report genomes of crAssphages from feces of one South African woman and three infants. Across the complete genome sequences of the South African crAssphages described here, we identify particularly elevated positive selection in RNA polymerase and phage tail protein encoding genes, contrasted against purifying selection, genome-wide. We further validate these findings against a crAssphage genome from previous studies. Together, our results suggest hotspots of selection within crAssphage RNA polymerase and phage tail protein encoding genes are potentially mediated by interactions between crAssphages and their bacterial partners.
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13
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Quantification of Lysogeny Caused by Phage Coinfections in Microbial Communities from Biophysical Principles. mSystems 2020; 5:5/5/e00353-20. [PMID: 32934113 PMCID: PMC7498681 DOI: 10.1128/msystems.00353-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The association of temperate phages and bacterial hosts during lysogeny manipulates microbial dynamics from the oceans to the human gut. Lysogeny is well studied in laboratory models, but its environmental drivers remain unclear. Here, we quantified the probability of lysogenization caused by phage coinfections, a well-known trigger of lysogeny, in marine and gut microbial environments. Coinfections were quantified by developing a biophysical model that incorporated the traits of viral and bacterial communities. Lysogenization via coinfection was more frequent in highly productive environments like the gut, due to higher microbial densities and higher phage adsorption rates. At low cell densities, lysogenization occurred in bacteria with long duplication times. These results bridge the molecular understanding of lysogeny with the ecology of complex microbial communities. Temperate phages can associate with their bacterial host to form a lysogen, often modifying the phenotype of the host. Lysogens are dominant in the microbially dense environment of the mammalian gut. This observation contrasts with the long-standing hypothesis of lysogeny being favored at low microbial densities, such as in oligotrophic marine environments. Here, we hypothesized that phage coinfections—a well-understood molecular mechanism of lysogenization—increase at high microbial abundances. To test this hypothesis, we developed a biophysical model of coinfection for marine and gut microbiomes. The model stochastically sampled ranges of phage and bacterial concentrations, adsorption rates, lysogenic commitment times, and community diversity from each environment. In 90% of the sampled marine communities, less than 10% of the bacteria were predicted to be lysogenized via coinfection. In contrast, 25% of the sampled gut communities displayed more than 25% of lysogenization. The probability of lysogenization in the gut was a consequence of the higher densities and higher adsorption rates. These results suggest that, on average, coinfections can form two trillion lysogens in the human gut every day. In marine microbiomes, which were characterized by lower densities and phage adsorption rates, lysogeny via coinfection was still possible for communities with long lysogenic commitment times. Our study indicates that different physical factors causing coinfections can reconcile the traditional view of lysogeny at poor host growth (long commitment times) and the recent Piggyback-the-Winner framework proposing that lysogeny is favored in rich environments (high densities and adsorption rates). IMPORTANCE The association of temperate phages and bacterial hosts during lysogeny manipulates microbial dynamics from the oceans to the human gut. Lysogeny is well studied in laboratory models, but its environmental drivers remain unclear. Here, we quantified the probability of lysogenization caused by phage coinfections, a well-known trigger of lysogeny, in marine and gut microbial environments. Coinfections were quantified by developing a biophysical model that incorporated the traits of viral and bacterial communities. Lysogenization via coinfection was more frequent in highly productive environments like the gut, due to higher microbial densities and higher phage adsorption rates. At low cell densities, lysogenization occurred in bacteria with long duplication times. These results bridge the molecular understanding of lysogeny with the ecology of complex microbial communities.
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14
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Yang Y, Shen W, Zhong Q, Chen Q, He X, Baker JL, Xiong K, Jin X, Wang J, Hu F, Le S. Development of a Bacteriophage Cocktail to Constrain the Emergence of Phage-Resistant Pseudomonas aeruginosa. Front Microbiol 2020; 11:327. [PMID: 32194532 PMCID: PMC7065532 DOI: 10.3389/fmicb.2020.00327] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/14/2020] [Indexed: 12/31/2022] Open
Abstract
With the emergence of multidrug-resistant and extensively drug-resistant bacterial pathogens, phage therapy and other alternative or additional therapeutic modalities are receiving resurgent attention. One of the major obstacles in developing effective phage therapies is the evolution of phage resistance in the bacterial host. When Pseudomonas aeruginosa was infected with a phage that uses O-antigen as receptor, phage resistances typically achieved through changing or loss of O-antigen structure. In this study, we showed that dsRNA phage phiYY uses core lipopolysaccharide as receptor and therefore efficiently kills the O-antigen deletion mutants. Furthermore, by phage training, we obtained PaoP5-m1, a derivative of dsDNA phage PaoP5, which is able to infect mutants with truncated O-antigen. We then generated a cocktail by mixing phiYY and PaoP5-m1 with additional three wide host range P. aeruginosa phages. The phage cocktail was effective against a diverse selection of clinical isolates of P. aeruginosa, and in the short-term constrained the appearance of the phage-resistant mutants that had beleaguered the effectiveness of single phage. Resistance to the 5-phage cocktail emerges after several days, and requires mutations in both wzy and migA Thus, this study provides an alternative strategy for designing phage cocktail and phage therapy.
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Affiliation(s)
- Yuhui Yang
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Wei Shen
- Department of Medical Laboratory, The General Hospital of Western Theater Command, Chengdu, China
| | - Qiu Zhong
- Department of Clinical Laboratory, Daping Hospital, Army Medical University, Chongqing, China
| | - Qian Chen
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Xuesong He
- The Forsyth Institute, Cambridge, MA, United States
| | - Jonathon L Baker
- Genomic Medicine Group, J. Craig Venter Institute, La Jolla, CA, United States
| | - Kun Xiong
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Xiaoling Jin
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Jing Wang
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Fuquan Hu
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Shuai Le
- Department of Microbiology, Army Medical University, Chongqing, China
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15
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Rates of Molecular Evolution in a Marine Synechococcus Phage Lineage. Viruses 2019; 11:v11080720. [PMID: 31390807 PMCID: PMC6722890 DOI: 10.3390/v11080720] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/27/2019] [Accepted: 07/31/2019] [Indexed: 12/30/2022] Open
Abstract
Cyanophages are characterized by vast genomic diversity and the formation of stable ecotypes over time. The evolution of phage diversity includes vertical processes, such as mutation, and horizontal processes, such as recombination and gene transfer. Here, we study the contribution of vertical and horizontal processes to short-term evolution of marine cyanophages. Analyzing time series data of Synechococcus-infecting Myoviridae ecotypes spanning up to 17 years, we found a high contribution of recombination relative to mutation (r/m) in all ecotypes. Additionally, we found a molecular clock of substitution and recombination in one ecotype, RIM8. The estimated RIM8 evolutionary rates are 2.2 genome-wide substitutions per year (1.275 × 10−5 substitutions/site/year) and 29 genome-wide nucleotide alterations due to recombination per year. We found 26 variable protein families, of which only two families have a predicted functional annotation, suggesting that they are auxiliary metabolic genes with bacterial homologs. A comparison of our rate estimates to other phage evolutionary rate estimates in the literature reveals a negative correlation of phage substitution rates with their genome size. A comparison to evolutionary rates in bacterial organisms further shows that phages have high rates of mutation and recombination compared to their bacterial hosts. We conclude that the increased recombination rate in phages likely contributes to their vast genomic diversity.
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16
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Resistance in marine cyanobacteria differs against specialist and generalist cyanophages. Proc Natl Acad Sci U S A 2019; 116:16899-16908. [PMID: 31383764 PMCID: PMC6708340 DOI: 10.1073/pnas.1906897116] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Long-term coexistence between unicellular cyanobacteria and their lytic viruses (cyanophages) in the oceans is thought to be due to the presence of sensitive cells in which cyanophages reproduce, ultimately killing the cell, while other cyanobacteria survive due to resistance to infection. Here, we investigated resistance in marine cyanobacteria from the genera Synechococcus and Prochlorococcus and compared modes of resistance against specialist and generalist cyanophages belonging to the T7-like and T4-like cyanophage families. Resistance was extracellular in most interactions against specialist cyanophages irrespective of the phage family, preventing entry into the cell. In contrast, resistance was intracellular in practically all interactions against generalist T4-like cyanophages. The stage of intracellular arrest was interaction-specific, halting at various stages of the infection cycle. Incomplete infection cycles proceeded to various degrees of phage genome transcription and translation as well as phage genome replication in numerous interactions. In a particularly intriguing case, intracellular capsid assembly was observed, but the phage genome was not packaged. The cyanobacteria survived the encounter despite late-stage infection and partial genome degradation. We hypothesize that this is tolerated due to genome polyploidy, which we found for certain strains of both Synechococcus and Prochlorococcus Our findings unveil a heavy cost of promiscuous entry of generalist phages into nonhost cells that is rarely paid by specialist phages and suggests the presence of unknown mechanisms of intracellular resistance in the marine unicellular cyanobacteria. Furthermore, these findings indicate that the range for virus-mediated horizontal gene transfer extends beyond hosts to nonhost cyanobacterial cells.
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17
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Flores-Uribe J, Philosof A, Sharon I, Fridman S, Larom S, Béjà O. A novel uncultured marine cyanophage lineage with lysogenic potential linked to a putative marine Synechococcus 'relic' prophage. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:598-604. [PMID: 31125500 DOI: 10.1111/1758-2229.12773] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
Marine cyanobacteria are important contributors to primary production in the ocean and their viruses (cyanophages) affect the ocean microbial communities. Despite reports of lysogeny in marine cyanobacteria, a genome sequence of such temperate cyanophages remains unknown although genomic analysis indicate potential for lysogeny in certain marine cyanophages. Using assemblies from Red Sea and Tara Oceans metagenomes, we recovered genomes of a novel uncultured marine cyanophage lineage, which contain, in addition to common cyanophage genes, a phycobilisome degradation protein NblA, an integrase and a split DNA polymerase. The DNA polymerase forms a monophyletic clade with a DNA polymerase from a genomic island in Synechococcus WH8016. The island contains a relic prophage that does not resemble any previously reported cyanophage but shares several genes with the newly identified cyanophages reported here. Metagenomic recruitment indicates that the novel cyanophages are widespread, albeit at low abundance. Here, we describe a novel potentially lysogenic cyanophage family, their abundance and distribution in the marine environment.
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Affiliation(s)
- José Flores-Uribe
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Alon Philosof
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, 32000, Israel
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91106, USA
| | - Itai Sharon
- Migal Galilee Research Institute, Kiryat Shmona, 11016, Israel
- Tel Hai College, Upper Galilee, 12210, Israel
| | - Svetlana Fridman
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Shirley Larom
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Oded Béjà
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, 32000, Israel
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18
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Larsen ML, Wilhelm SW, Lennon JT. Nutrient stoichiometry shapes microbial coevolution. Ecol Lett 2019; 22:1009-1018. [DOI: 10.1111/ele.13252] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/10/2018] [Accepted: 02/18/2019] [Indexed: 01/07/2023]
Affiliation(s)
- Megan L. Larsen
- Department of Biology Indiana University Bloomington IN47405USA
| | - Steven W. Wilhelm
- Department of Microbiology University of Tennessee Knoxville TN37996 USA
| | - Jay T. Lennon
- Department of Biology Indiana University Bloomington IN47405USA
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19
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Kupczok A, Neve H, Huang KD, Hoeppner MP, Heller KJ, Franz CMAP, Dagan T. Rates of Mutation and Recombination in Siphoviridae Phage Genome Evolution over Three Decades. Mol Biol Evol 2019; 35:1147-1159. [PMID: 29688542 PMCID: PMC5913663 DOI: 10.1093/molbev/msy027] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The evolution of asexual organisms is driven not only by the inheritance of genetic modification but also by the acquisition of foreign DNA. The contribution of vertical and horizontal processes to genome evolution depends on their rates per year and is quantified by the ratio of recombination to mutation. These rates have been estimated for bacteria; however, no estimates have been reported for phages. Here, we delineate the contribution of mutation and recombination to dsDNA phage genome evolution. We analyzed 34 isolates of the 936 group of Siphoviridae phages using a Lactococcus lactis strain from a single dairy over 29 years. We estimate a constant substitution rate of 1.9 × 10−4 substitutions per site per year due to mutation that is within the range of estimates for eukaryotic RNA and DNA viruses. The reconstruction of recombination events reveals a constant rate of five recombination events per year and 4.5 × 10−3 nucleotide alterations due to recombination per site per year. Thus, the recombination rate exceeds the substitution rate, resulting in a relative effect of recombination to mutation (r/m) of ∼24 that is homogenous over time. Especially in the early transcriptional region, we detect frequent gene loss and regain due to recombination with phages of the 936 group, demonstrating the role of the 936 group pangenome as a reservoir of genetic variation. The observed substitution rate homogeneity conforms to the neutral theory of evolution; hence, the neutral theory can be applied to phage genome evolution and also to genetic variation brought about by recombination.
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Affiliation(s)
- Anne Kupczok
- Genomic Microbiology Group, Institute of General Microbiology, Kiel University, Kiel, Germany
| | - Horst Neve
- Department of Microbiology and Biotechnology, Max Rubner-Institut (Federal Research Institute of Nutrition and Food), Kiel, Germany
| | - Kun D Huang
- Genomic Microbiology Group, Institute of General Microbiology, Kiel University, Kiel, Germany
| | - Marc P Hoeppner
- Institute of Clinical Molecular Biology (IKMB), Kiel University, Kiel, Germany
| | - Knut J Heller
- Department of Microbiology and Biotechnology, Max Rubner-Institut (Federal Research Institute of Nutrition and Food), Kiel, Germany
| | - Charles M A P Franz
- Department of Microbiology and Biotechnology, Max Rubner-Institut (Federal Research Institute of Nutrition and Food), Kiel, Germany
| | - Tal Dagan
- Genomic Microbiology Group, Institute of General Microbiology, Kiel University, Kiel, Germany
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20
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Host Resistance, Genomics and Population Dynamics in a Salmonella Enteritidis and Phage System. Viruses 2019; 11:v11020188. [PMID: 30813274 PMCID: PMC6410252 DOI: 10.3390/v11020188] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 02/04/2019] [Accepted: 02/13/2019] [Indexed: 12/13/2022] Open
Abstract
Bacteriophages represent an alternative solution to control bacterial infections. When interacting, bacteria and phage can evolve, and this relationship is described as antagonistic coevolution, a pattern that does not fit all models. In this work, the model consisted of a microcosm of Salmonella enterica serovar Enteritidis and φSan23 phage. Samples were taken for 12 days every 48 h. Bacteria and phage samples were collected; and isolated bacteria from each time point were challenged against phages from previous, contemporary, and subsequent time points. The phage plaque tests, with the genomics analyses, showed a mutational asymmetry dynamic in favor of the bacteria instead of antagonistic coevolution. This is important for future phage-therapy applications, so we decided to explore the population dynamics of Salmonella under different conditions: pressure of one phage, a combination of phages, and phages plus an antibiotic. The data from cultures with single and multiple phages, and antibiotics, were used to create a mathematical model exploring population and resistance dynamics of Salmonella under these treatments, suggesting a nonlethal, growth-inhibiting antibiotic may decrease resistance to phage-therapy cocktails. These data provide a deep insight into bacterial dynamics under different conditions and serve as additional criteria to select phages and antibiotics for phage-therapy.
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21
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Enav H, Kirzner S, Lindell D, Mandel-Gutfreund Y, Béjà O. Adaptation to sub-optimal hosts is a driver of viral diversification in the ocean. Nat Commun 2018; 9:4698. [PMID: 30409965 PMCID: PMC6224464 DOI: 10.1038/s41467-018-07164-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/22/2018] [Indexed: 12/16/2022] Open
Abstract
Cyanophages of the Myoviridae family include generalist viruses capable of infecting a wide range of hosts including those from different cyanobacterial genera. While the influence of phages on host evolution has been studied previously, it is not known how the infection of distinct hosts influences the evolution of cyanophage populations. Here, using an experimental evolution approach, we investigated the adaptation of multiple cyanophage populations to distinct cyanobacterial hosts. We show that when infecting an "optimal" host, whose infection is the most efficient, phage populations accumulated only a few mutations. However, when infecting "sub-optimal" hosts, different mutations spread in the phage populations, leading to rapid diversification into distinct subpopulations. Based on our results, we propose a model demonstrating how shifts in microbial abundance, which lead to infection of "sub-optimal" hosts, act as a driver for rapid diversification of viral populations.
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Affiliation(s)
- Hagay Enav
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel. .,Department of Microbiome Science, Max-Planck Institute for Developmental Biology, 72076, Tübingen, Germany.
| | - Shay Kirzner
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Debbie Lindell
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Yael Mandel-Gutfreund
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel.,Department of Computer Sciences, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Oded Béjà
- Faculty of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel.
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22
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de Jonge PA, Nobrega FL, Brouns SJJ, Dutilh BE. Molecular and Evolutionary Determinants of Bacteriophage Host Range. Trends Microbiol 2018; 27:51-63. [PMID: 30181062 DOI: 10.1016/j.tim.2018.08.006] [Citation(s) in RCA: 208] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/07/2018] [Accepted: 08/13/2018] [Indexed: 01/12/2023]
Abstract
The host range of a bacteriophage is the taxonomic diversity of hosts it can successfully infect. Host range, one of the central traits to understand in phages, is determined by a range of molecular interactions between phage and host throughout the infection cycle. While many well studied model phages seem to exhibit a narrow host range, recent ecological and metagenomics studies indicate that phages may have specificities that range from narrow to broad. There is a growing body of studies on the molecular mechanisms that enable phages to infect multiple hosts. These mechanisms, and their evolution, are of considerable importance to understanding phage ecology and the various clinical, industrial, and biotechnological applications of phage. Here we review knowledge of the molecular mechanisms that determine host range, provide a framework defining broad host range in an evolutionary context, and highlight areas for additional research.
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Affiliation(s)
- Patrick A de Jonge
- Theoretical Biology and Bioinformatics, Utrecht University, Padualaan 8 3584 CH Utrecht, The Netherlands; Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9 2629 HZ, Delft, The Netherlands
| | - Franklin L Nobrega
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9 2629 HZ, Delft, The Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9 2629 HZ, Delft, The Netherlands; Laboratory for Microbiology, Wageningen University, Stippeneng 4 6708 WE, Wageningen, The Netherlands; These authors made equal contributions
| | - Bas E Dutilh
- Theoretical Biology and Bioinformatics, Utrecht University, Padualaan 8 3584 CH Utrecht, The Netherlands; Centre for Molecular and Biomolecular Informatics, Radboud University Medical Centre, Geert Grooteplein Zuid 26-28, 6525GA Nijmegen, The Netherlands; These authors made equal contributions.
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23
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Genetic Diversity and Cooccurrence Patterns of Marine Cyanopodoviruses and Picocyanobacteria. Appl Environ Microbiol 2018; 84:AEM.00591-18. [PMID: 29915108 DOI: 10.1128/aem.00591-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/08/2018] [Indexed: 01/27/2023] Open
Abstract
Picocyanobacteria Prochlorococcus and Synechococcus are abundant in the global oceans and subject to active viral infection. In this study, the genetic diversity of picocyanobacteria and the genetic diversity of cyanopodoviruses were synchronously investigated along water columns in the equatorial Indian Ocean and over a seasonal time course in the coastal Sanya Bay, South China Sea. Using the 16S-23S rRNA internal transcribed spacer (ITS)-based clone library and quantitative PCR (qPCR) analyses, the picocyanobacterial community composition and abundance were determined. Sanya Bay was dominated by clade II Synechococcus during all the seasons, and a typical population shift from high-light-adapted Prochlorococcus to low-light-adapted Prochlorococcus was found along the vertical profiles. Strikingly, the DNA polymerase gene sequences of cyanopodoviruses revealed a much greater genetic diversity than we expected. Nearly one-third of the phylogenetic groups were newly described here. No apparent seasonal pattern was observed for the Sanya Bay picocyanobacterial or cyanopodoviral communities. Different dominant cyanopodovirus lineages were identified for the coastal area, upper euphotic zone, and middle-to-lower euphotic zone of the open ocean. Diversity indices of both picocyanobacteria and cyanopodoviruses were highest in the middle euphotic zone and both were lower in the upper euphotic zone, reflecting a host-virus interaction. Cyanopodoviral communities differed significantly between the upper euphotic zone and the middle-to-lower euphotic zone, showing a vertical pattern similar to that of picocyanobacteria. However, in the surface waters of the open ocean, cyanopodoviruses exhibited no apparent biogeographic pattern, differing from picocyanobacteria. This study demonstrates correlated distribution patterns of picocyanobacteria and cyanopodoviruses, as well as the complex biogeography of cyanopodoviruses.IMPORTANCE Picocyanobacteria are highly diverse and abundant in the ocean and display remarkable global biogeography and a vertical distribution pattern. However, how the diversity and distribution of picocyanobacteria affect those of the viruses that infect them remains largely unknown. Here we synchronously analyzed the community structures of cyanopodoviruses and picocyanobacteria at spatial and temporal scales. Both spatial and temporal variations of cyanopodoviral communities can be linked to those of picocyanobacteria. The coastal area, upper euphotic zone, and middle-to-lower euphotic zone of the open ocean have distinct cyanopodoviral communities, showing horizontal and vertical variation patterns closely related to those of picocyanobacteria. These findings emphasize the driving force of host community in shaping the biogeographic structure of viruses. Our work provides important information for future assessments of the ecological roles of viruses and hosts for each other.
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Abstract
Viruses infect all kingdoms of marine life from bacteria to whales. Viruses in the world's oceans play important roles in the mortality of phytoplankton, and as drivers of evolution and biogeochemical cycling. They shape host population abundance and distribution and can lead to the termination of algal blooms. As discoveries about this huge reservoir of genetic and biological diversity grow, our understanding of the major influences viruses exert in the global marine environment continues to expand. This chapter discusses the key discoveries that have been made to date about marine viruses and the current direction of this field of research.
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Affiliation(s)
- Karen D Weynberg
- School of Chemistry & Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia.
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25
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Abstract
Marine microbial communities exert a large influence on ocean ecosystem processes, and viruses in these communities play key roles in controlling microbial abundances, nutrient cycling, and productivity. We show here that dominant viruses in the open ocean persist for long time periods and that many appear tightly locked in coordinated diel oscillations with their bacterial hosts. The persistent structure of viral assemblages, as well as synchronized daily oscillations of viruses and hosts, are in part the result of the regular diurnal coupling of viral and host replication cycles. Collectively, our results suggest that viruses, as key components of marine ecosystems, are intrinsically synchronized with the daily rhythms of microbial community processes in the ocean’s photic zone. Viruses are fundamental components of marine microbial communities that significantly influence oceanic productivity, biogeochemistry, and ecosystem processes. Despite their importance, the temporal activities and dynamics of viral assemblages in natural settings remain largely unexplored. Here we report the transcriptional activities and variability of dominant dsDNA viruses in the open ocean’s euphotic zone over daily and seasonal timescales. While dsDNA viruses exhibited some fluctuation in abundance in both cellular and viral size fractions, the viral assemblage was remarkably stable, with the most abundant viral types persisting over many days. More extended time series indicated that long-term persistence (>1 y) was the rule for most dsDNA viruses observed, suggesting that both core viral genomes as well as viral community structure were conserved over interannual periods. Viral gene transcription in host cell assemblages revealed diel cycling among many different viral types. Most notably, an afternoon peak in cyanophage transcriptional activity coincided with a peak in Prochlorococcus DNA replication, indicating coordinated diurnal coupling of virus and host reproduction. In aggregate, our analyses suggested a tightly synchronized diel coupling of viral and cellular replication cycles in both photoautotrophic and heterotrophic bacterial hosts. A surprising consequence of these findings is that diel cycles in the ocean’s photic zone appear to be universal organizing principles that shape ecosystem dynamics, ecological interactions, and biogeochemical cycling of both cellular and acellular community components.
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