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Vijayan N, McAnulty SJ, Sanchez G, Jolly J, Ikeda Y, Nishiguchi MK, Réveillac E, Gestal C, Spady BL, Li DH, Burford BP, Kerwin AH, Nyholm SV. Evolutionary history influences the microbiomes of a female symbiotic reproductive organ in cephalopods. Appl Environ Microbiol 2024; 90:e0099023. [PMID: 38315021 PMCID: PMC10952459 DOI: 10.1128/aem.00990-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 12/09/2023] [Indexed: 02/07/2024] Open
Abstract
Many female squids and cuttlefishes have a symbiotic reproductive organ called the accessory nidamental gland (ANG) that hosts a bacterial consortium involved with egg defense against pathogens and fouling organisms. While the ANG is found in multiple cephalopod families, little is known about the global microbial diversity of these ANG bacterial symbionts. We used 16S rRNA gene community analysis to characterize the ANG microbiome from different cephalopod species and assess the relationship between host and symbiont phylogenies. The ANG microbiome of 11 species of cephalopods from four families (superorder: Decapodiformes) that span seven geographic locations was characterized. Bacteria of class Alphaproteobacteria, Gammaproteobacteria, and Flavobacteriia were found in all species, yet analysis of amplicon sequence variants by multiple distance metrics revealed a significant difference between ANG microbiomes of cephalopod families (weighted/unweighted UniFrac, Bray-Curtis, P = 0.001). Despite being collected from widely disparate geographic locations, members of the family Sepiolidae (bobtail squid) shared many bacterial taxa including (~50%) Opitutae (Verrucomicrobia) and Ruegeria (Alphaproteobacteria) species. Furthermore, we tested for phylosymbiosis and found a positive correlation between host phylogenetic distance and bacterial community dissimilarity (Mantel test r = 0.7). These data suggest that closely related sepiolids select for distinct symbionts from similar bacterial taxa. Overall, the ANGs of different cephalopod species harbor distinct microbiomes and thus offer a diverse symbiont community to explore antimicrobial activity and other functional roles in host fitness.IMPORTANCEMany aquatic organisms recruit microbial symbionts from the environment that provide a variety of functions, including defense from pathogens. Some female cephalopods (squids, bobtail squids, and cuttlefish) have a reproductive organ called the accessory nidamental gland (ANG) that contains a bacterial consortium that protects eggs from pathogens. Despite the wide distribution of these cephalopods, whether they share similar microbiomes is unknown. Here, we studied the microbial diversity of the ANG in 11 species of cephalopods distributed over a broad geographic range and representing 15-120 million years of host divergence. The ANG microbiomes shared some bacterial taxa, but each cephalopod species had unique symbiotic members. Additionally, analysis of host-symbiont phylogenies suggests that the evolutionary histories of the partners have been important in shaping the ANG microbiome. This study advances our knowledge of cephalopod-bacteria relationships and provides a foundation to explore defensive symbionts in other systems.
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Affiliation(s)
- Nidhi Vijayan
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Sarah J. McAnulty
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Gustavo Sanchez
- Molecular Genetics Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
- Graduate School of Integrated Science for Life, Hiroshima University, Hiroshima, Japan
| | - Jeffrey Jolly
- Molecular Genetics Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
- Marine Climate Change Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Yuzuru Ikeda
- Department of Chemistry, Biology and Marine Science, Faculty of Science, University of Ryukyus, Ryukyus, Japan
| | - Michele K. Nishiguchi
- Department of Molecular and Cell Biology, University of California, Merced, California, USA
| | - Elodie Réveillac
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS–La Rochelle Université, La Rochelle, France
| | - Camino Gestal
- Institute of Marine Research (IIM), CSIC, Vigo, Spain
| | - Blake L. Spady
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- U.S. National Oceanic and Atmospheric Administration, National Environmental Satellite Data and Information Service, Center for Satellite Applications and Research, Coral Reef Watch, College Park, Maryland, USA
| | - Diana H. Li
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, New York, USA
| | - Benjamin P. Burford
- Institute of Marine Sciences, University of California, affiliated with the National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southwest Fisheries Science Center, Santa Cruz, California, USA
| | - Allison H. Kerwin
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
- Department of Biology, McDaniel College, Westminster, Maryland, USA
| | - Spencer V. Nyholm
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
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2
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Baden T, Briseño J, Coffing G, Cohen-Bodénès S, Courtney A, Dickerson D, Dölen G, Fiorito G, Gestal C, Gustafson T, Heath-Heckman E, Hua Q, Imperadore P, Kimbara R, Król M, Lajbner Z, Lichilín N, Macchi F, McCoy MJ, Nishiguchi MK, Nyholm SV, Otjacques E, Pérez-Ferrer PA, Ponte G, Pungor JR, Rogers TF, Rosenthal JJC, Rouressol L, Rubas N, Sanchez G, Santos CP, Schultz DT, Seuntjens E, Songco-Casey JO, Stewart IE, Styfhals R, Tuanapaya S, Vijayan N, Weissenbacher A, Zifcakova L, Schulz G, Weertman W, Simakov O, Albertin CB. Cephalopod-omics: Emerging Fields and Technologies in Cephalopod Biology. Integr Comp Biol 2023; 63:1226-1239. [PMID: 37370232 PMCID: PMC10755191 DOI: 10.1093/icb/icad087] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Few animal groups can claim the level of wonder that cephalopods instill in the minds of researchers and the general public. Much of cephalopod biology, however, remains unexplored: the largest invertebrate brain, difficult husbandry conditions, and complex (meta-)genomes, among many other things, have hindered progress in addressing key questions. However, recent technological advancements in sequencing, imaging, and genetic manipulation have opened new avenues for exploring the biology of these extraordinary animals. The cephalopod molecular biology community is thus experiencing a large influx of researchers, emerging from different fields, accelerating the pace of research in this clade. In the first post-pandemic event at the Cephalopod International Advisory Council (CIAC) conference in April 2022, over 40 participants from all over the world met and discussed key challenges and perspectives for current cephalopod molecular biology and evolution. Our particular focus was on the fields of comparative and regulatory genomics, gene manipulation, single-cell transcriptomics, metagenomics, and microbial interactions. This article is a result of this joint effort, summarizing the latest insights from these emerging fields, their bottlenecks, and potential solutions. The article highlights the interdisciplinary nature of the cephalopod-omics community and provides an emphasis on continuous consolidation of efforts and collaboration in this rapidly evolving field.
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Affiliation(s)
- Tom Baden
- School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - John Briseño
- Molecular and Cell Biology Department, University of Connecticut, Storrs, CT 06269, USA
| | - Gabrielle Coffing
- Biology Department: Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403-5289, USA
| | - Sophie Cohen-Bodénès
- Laboratoire des Systèmes Perceptifs, Département d'Etudes Cognitives, Ecole Normale Supérieure, PSL University, CNRS, 75005 Paris, France
| | - Amy Courtney
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Dominick Dickerson
- Friday Harbor Laboratory, University of Washington, Seattle, WA 98250, USA
| | - Gül Dölen
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Graziano Fiorito
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
| | - Camino Gestal
- Laboratory of Marine Molecular Pathobiology, Institute of Marine Research (IIM), Spanish National Research Council (CSIC), Vigo 36208, Spain
| | | | - Elizabeth Heath-Heckman
- Departments of Integrative Biology and Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Qiaz Hua
- Department of Ecology and Evolution, University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Pamela Imperadore
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
| | - Ryosuke Kimbara
- Misaki Marine Biological Station, School of Science, The University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Mirela Król
- Adam Mickiewicz University in Poznań, Poznań 61-712, Poland
| | - Zdeněk Lajbner
- Physics and Biology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Kunigami District, Okinawa 904-0495, Japan
| | - Nicolás Lichilín
- Department of Neurosciences and Developmental Biology, University of Vienna, Vienna 1010, Austria
| | - Filippo Macchi
- Program in Biology, New York University Abu Dhabi, P.O. Box 129188 Abu Dhabi, United Arab Emirates
| | - Matthew J McCoy
- Department of Pathology, Stanford University, Stanford, CA 94305, USA
| | - Michele K Nishiguchi
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, 5200 N. Lake Blvd., Merced, CA 95343, USA
| | - Spencer V Nyholm
- Molecular and Cell Biology Department, University of Connecticut, Storrs, CT 06269, USA
| | - Eve Otjacques
- MARE—Marine and Environmental Sciences Centre & ARNET—Aquatic Research Network, Laboratório Marítimo da Guia, Faculdade de Ciências, Universidade de Lisboa, Av. Nossa Senhora do Cabo, 939, 2750-374 Cascais, Portugal
- Division of Biosphere Sciences and Engineering, Carnegie Institution for Science, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Pedro Antonio Pérez-Ferrer
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, 5200 N. Lake Blvd., Merced, CA 95343, USA
| | - Giovanna Ponte
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
| | - Judit R Pungor
- Biology Department: Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403-5289, USA
| | - Thea F Rogers
- Department of Neurosciences and Developmental Biology, University of Vienna, Vienna 1010, Austria
| | - Joshua J C Rosenthal
- Marine Biological Laboratory, The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Woods Hole, MA 02543-1015, USA
| | - Lisa Rouressol
- Department of Neurosciences and Developmental Biology, University of Vienna, Vienna 1010, Austria
| | - Noelle Rubas
- Department of Molecular Biosciences and Bioengineering, University of Hawaii Manoa, Honolulu, HI 96822, USA
| | - Gustavo Sanchez
- Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Catarina Pereira Santos
- MARE—Marine and Environmental Sciences Centre & ARNET—Aquatic Research Network, Laboratório Marítimo da Guia, Faculdade de Ciências, Universidade de Lisboa, Av. Nossa Senhora do Cabo, 939, 2750-374 Cascais, Portugal
| | - Darrin T Schultz
- Department of Neurosciences and Developmental Biology, University of Vienna, Vienna 1010, Austria
| | - Eve Seuntjens
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven 3000, Belgium
| | - Jeremea O Songco-Casey
- Biology Department: Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403-5289, USA
| | - Ian Erik Stewart
- Neural Circuits and Behaviour Lab, Max‐Delbrück‐Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin 13125, Germany
| | - Ruth Styfhals
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven 3000, Belgium
| | - Surangkana Tuanapaya
- Laboratory of genetics and applied breeding of molluscs, Fisheries College, Ocean University of China, Qingdao 266100, China
| | - Nidhi Vijayan
- Molecular and Cell Biology Department, University of Connecticut, Storrs, CT 06269, USA
| | | | - Lucia Zifcakova
- Physics and Biology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Kunigami District, Okinawa 904-0495, Japan
| | | | - Willem Weertman
- Friday Harbor Laboratory, University of Washington, Seattle, WA 98250, USA
| | - Oleg Simakov
- Department of Neurosciences and Developmental Biology, University of Vienna, Vienna 1010, Austria
| | - Caroline B Albertin
- Marine Biological Laboratory, The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Woods Hole, MA 02543-1015, USA
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Bongrand C, Foster JS. Modelled microgravity impacts Vibrio fischeri population structure in a mutualistic association with an animal host. Environ Microbiol 2023; 25:3269-3279. [PMID: 37828645 DOI: 10.1111/1462-2920.16522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023]
Abstract
Perturbations to host-microbe interactions, such as environmental stress, can alter and disrupt homeostasis. In this study, we examined the effects of a stressor, simulated microgravity, on beneficial bacteria behaviours when colonising their host. We studied the bacterium Vibrio fischeri, which establishes a mutualistic association in a symbiosis-specific organ within the bobtail squid, Euprymna scolopes. To elucidate how animal-microbe interactions are affected by the stress of microgravity, squid were inoculated with different bacterial strains exhibiting either a dominant- or sharing-colonisation behaviour in High Aspect Ratio Vessels, which simulate the low-shear environment of microgravity. The colonisation behaviours of the sharing and dominant strains under modelled microgravity conditions were determined by counting light-organ homogenate of squids as well as confocal microscopy to assess the partitioning of different strains within the light organ. The results indicated that although the colonisation behaviours of the strains did not change, the population levels of the sharing strains were at lower relative abundance in single-colonised animals exposed to modelled microgravity compared to unit gravity; in addition, there were shifts in the relative abundance of strains in co-colonised squids. Together these results suggest that the initiation of beneficial interactions between microbes and animals can be altered by environmental stress, such as simulated microgravity.
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Affiliation(s)
- Clotilde Bongrand
- Department of Microbiology and Cell Science, Space Life Sciences Lab, University of Florida, Merritt Island, Florida, USA
| | - Jamie S Foster
- Department of Microbiology and Cell Science, Space Life Sciences Lab, University of Florida, Merritt Island, Florida, USA
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4
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Ganesan R, Wierz JC, Kaltenpoth M, Flórez LV. How It All Begins: Bacterial Factors Mediating the Colonization of Invertebrate Hosts by Beneficial Symbionts. Microbiol Mol Biol Rev 2022; 86:e0012621. [PMID: 36301103 PMCID: PMC9769632 DOI: 10.1128/mmbr.00126-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Beneficial associations with bacteria are widespread across animals, spanning a range of symbiont localizations, transmission routes, and functions. While some of these associations have evolved into obligate relationships with permanent symbiont localization within the host, the majority require colonization of every host generation from the environment or via maternal provisions. Across the broad diversity of host species and tissue types that beneficial bacteria can colonize, there are some highly specialized strategies for establishment yet also some common patterns in the molecular basis of colonization. This review focuses on the mechanisms underlying the early stage of beneficial bacterium-invertebrate associations, from initial contact to the establishment of the symbionts in a specific location of the host's body. We first reflect on general selective pressures that can drive the transition from a free-living to a host-associated lifestyle in bacteria. We then cover bacterial molecular factors for colonization in symbioses from both model and nonmodel invertebrate systems where these have been studied, including terrestrial and aquatic host taxa. Finally, we discuss how interactions between multiple colonizing bacteria and priority effects can influence colonization. Taking the bacterial perspective, we emphasize the importance of developing new experimentally tractable systems to derive general insights into the ecological factors and molecular adaptations underlying the origin and establishment of beneficial symbioses in animals.
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Affiliation(s)
- Ramya Ganesan
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Jürgen C. Wierz
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Martin Kaltenpoth
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Laura V. Flórez
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Plant and Environmental Sciences, Section for Organismal Biology, University of Copenhagen, Copenhagen, Denmark
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5
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A Putative Lipoprotein Mediates Cell-Cell Contact for Type VI Secretion System-Dependent Killing of Specific Competitors. mBio 2022; 13:e0308521. [PMID: 35404117 PMCID: PMC9040878 DOI: 10.1128/mbio.03085-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Interbacterial competition is prevalent in host-associated microbiota, where it can shape community structure and function, impacting host health in both positive and negative ways. However, the factors that permit bacteria to discriminate among their various neighbors for targeted elimination of competitors remain elusive. We identified a putative lipoprotein (TasL) in Vibrio species that mediates cell-cell attachment with a subset of target strains, allowing inhibitors to target specific competitors for elimination. Here, we describe this putative lipoprotein, which is associated with the broadly distributed type VI secretion system (T6SS), by studying symbiotic Vibrio fischeri, which uses the T6SS to compete for colonization sites in their squid host. We demonstrate that TasL allows V. fischeri cells to restrict T6SS-dependent killing to certain genotypes by selectively integrating competitor cells into aggregates while excluding other cell types. TasL is also required for T6SS-dependent competition within juvenile squid, indicating that the adhesion factor is active in the host. Because TasL homologs are found in other host-associated bacterial species, this newly described cell-cell attachment mechanism has the potential to impact microbiome structure within diverse hosts. IMPORTANCE T6SSs are broadly distributed interbacterial weapons that share an evolutionary history with bacteriophage. Because the T6SS can be used to kill neighboring cells, it can impact the spatial distribution and biological function of both free-living and host-associated microbial communities. Like their phage relatives, T6SS+ cells must sufficiently bind competitor cells to deliver their toxic effector proteins through the syringe-like apparatus. Although phage use receptor-binding proteins (RBPs) and tail fibers to selectively bind prey cells, the biophysical properties that mediate this cell-cell contact for T6SS-mediated killing remain unknown. Here, we identified a large, predicted lipoprotein that is coordinately expressed with T6SS proteins and facilitates the contact that is necessary for the T6SS-dependent elimination of competitors in a natural host. Similar to phage RBPs and tail fibers, this lipoprotein is required for T6SS+ cells to discriminate between prey and nonprey cell types, revealing new insight into prey selection during T6SS-mediated competition.
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Bongrand C, Koch E, Mende D, Romano A, Lawhorn S, McFall-Ngai M, DeLong EF, Ruby EG. Evidence of Genomic Diversification in a Natural Symbiotic Population Within Its Host. Front Microbiol 2022; 13:854355. [PMID: 35300477 PMCID: PMC8922018 DOI: 10.3389/fmicb.2022.854355] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/09/2022] [Indexed: 11/25/2022] Open
Abstract
Planktonic cells of the luminous marine bacterium Vibrio fischeri establish themselves in the light-emitting organ of each generation of newly hatched Euprymna scolopes bobtail squid. A symbiont population is maintained within the 6 separated crypts of the organ for the ∼9-month life of the host. In the wild, the initial colonization step is typically accomplished by a handful of planktonic V. fischeri cells, leading to a species-specific, but often multi-strain, symbiont population. Within a few hours, the inoculating cells proliferate within the organ’s individual crypts, after which there is evidently no supernumerary colonization. Nevertheless, every day at dawn, the majority of the symbionts is expelled, and the regrowth of the remaining ∼5% of cells provides a daily opportunity for the population to evolve and diverge, thereby increasing its genomic diversity. To begin to understand the extent of this diversification, we characterized the light-organ population of an adult animal. First, we used 16S sequencing to determine that species in the V. fischeri clade were essentially the only ones detectable within a field-caught E. scolopes. Efforts to colonize the host with a minor species that appeared to be identified, V. litoralis, revealed that, although some cells could be imaged within the organ, they were <0.1% of the typical V. fischeri population, and did not persist. Next, we determined the genome sequences of seventy-two isolates from one side of the organ. While all these isolates were associated with one of three clusters of V. fischeri strains, there was considerable genomic diversity within this natural symbiotic population. Comparative analyses revealed a significant difference in both the number and the presence/absence of genes within each cluster; in contrast, there was little accumulation of single-nucleotide polymorphisms. These data suggest that, in nature, the light organ is colonized by a small number of V. fischeri strains that can undergo significant genetic diversification, including by horizontal-gene transfer, over the course of ∼1500 generations of growth in the organ. When the resulting population of symbionts is expelled into seawater, its genomic mix provides the genetic basis for selection during the subsequent environmental dispersal, and transmission to the next host.
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Affiliation(s)
- Clotilde Bongrand
- Kewalo Marine Laboratory, SOEST, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Eric Koch
- Kewalo Marine Laboratory, SOEST, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Daniel Mende
- Department of Oceanography, SOEST, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Anna Romano
- Department of Oceanography, SOEST, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Susannah Lawhorn
- Kewalo Marine Laboratory, SOEST, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Margaret McFall-Ngai
- Kewalo Marine Laboratory, SOEST, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Edward F DeLong
- Department of Oceanography, SOEST, University of Hawai'i at Mānoa, Honolulu, HI, United States
| | - Edward G Ruby
- Kewalo Marine Laboratory, SOEST, University of Hawai'i at Mānoa, Honolulu, HI, United States
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7
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Lynch JB, Bennett BD, Merrill BD, Ruby EG, Hryckowian AJ. Independent host- and bacterium-based determinants protect a model symbiosis from phage predation. Cell Rep 2022; 38:110376. [PMID: 35172163 PMCID: PMC8983117 DOI: 10.1016/j.celrep.2022.110376] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 11/08/2021] [Accepted: 01/20/2022] [Indexed: 01/21/2023] Open
Abstract
Bacteriophages (phages) are diverse and abundant constituents of microbial communities worldwide, capable of modulating bacterial populations in diverse ways. Here, we describe the phage HNL01, which infects the marine bacterium Vibrio fischeri. We use culture-based approaches to demonstrate that mutations in the exopolysaccharide locus of V. fischeri render this bacterium resistant to infection by HNL01, highlighting the extracellular matrix as a key determinant of HNL01 infection. Additionally, using the natural symbiosis between V. fischeri and the squid Euprymna scolopes, we show that, during colonization, V. fischeri is protected from phages present in the ambient seawater. Taken together, these findings shed light on independent yet synergistic host- and bacterium-based strategies for resisting symbiosis-disrupting phage predation, and we present important implications for understanding these strategies in the context of diverse host-associated microbial ecosystems.
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Affiliation(s)
- Jonathan B Lynch
- Pacific Biosciences Research Center, University of Hawai'i at Manoa, Honolulu, HI 96822, USA; Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Brittany D Bennett
- Pacific Biosciences Research Center, University of Hawai'i at Manoa, Honolulu, HI 96822, USA; Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Bryan D Merrill
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94304, USA
| | - Edward G Ruby
- Pacific Biosciences Research Center, University of Hawai'i at Manoa, Honolulu, HI 96822, USA
| | - Andrew J Hryckowian
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA; Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA.
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8
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Perreau J, Moran NA. Genetic innovations in animal-microbe symbioses. Nat Rev Genet 2021; 23:23-39. [PMID: 34389828 DOI: 10.1038/s41576-021-00395-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2021] [Indexed: 02/07/2023]
Abstract
Animal hosts have initiated myriad symbiotic associations with microorganisms and often have maintained these symbioses for millions of years, spanning drastic changes in ecological conditions and lifestyles. The establishment and persistence of these relationships require genetic innovations on the parts of both symbionts and hosts. The nature of symbiont innovations depends on their genetic population structure, categorized here as open, closed or mixed. These categories reflect modes of inter-host transmission that result in distinct genomic features, or genomic syndromes, in symbionts. Although less studied, hosts also innovate in order to preserve and control symbiotic partnerships. New capabilities to sequence host-associated microbial communities and to experimentally manipulate both hosts and symbionts are providing unprecedented insights into how genetic innovations arise under different symbiont population structures and how these innovations function to support symbiotic relationships.
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Affiliation(s)
- Julie Perreau
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
| | - Nancy A Moran
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA.
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9
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Host-Like Conditions Are Required for T6SS-Mediated Competition among Vibrio fischeri Light Organ Symbionts. mSphere 2021; 6:e0128820. [PMID: 34287008 PMCID: PMC8386388 DOI: 10.1128/msphere.01288-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bacteria employ diverse competitive strategies to enhance fitness and promote their own propagation. However, little is known about how symbiotic bacteria modulate competitive mechanisms as they compete for a host niche. The bacterium Vibrio fischeri forms a symbiotic relationship with marine animals and encodes a type VI secretion system (T6SS), which is a contact-dependent killing mechanism used to eliminate competitors during colonization of the Euprymna scolopes squid light organ. Like other horizontally acquired symbionts, V. fischeri experiences changes in its physical and chemical environment during symbiosis establishment. Therefore, we probed both environmental and host-like conditions to identify ecologically relevant cues that control T6SS-dependent competition during habitat transition. Although the T6SS did not confer a competitive advantage for V. fischeri strain ES401 under planktonic conditions, a combination of both host-like pH and viscosity was necessary for T6SS competition. For ES401, high viscosity activates T6SS expression and neutral/acidic pH promotes cell-cell contact for killing, and this pH-dependent phenotype was conserved in the majority of T6SS-encoding strains examined. We also identified a subset of V. fischeri isolates that engaged in T6SS-mediated competition at high viscosity under both planktonic and host-like pH conditions. T6SS phylogeny revealed that strains with pH-dependent phenotypes cluster together to form a subclade within the pH-independent strains, suggesting that V. fischeri may have recently evolved to limit competition to the host niche. IMPORTANCE Bacteria have evolved diverse strategies to compete for limited space and resources. Because these mechanisms can be costly to use, their expression and function are often restricted to specific environments where the benefits outweigh the costs. However, little is known about the specific cues that modulate competitive mechanisms as bacterial symbionts transition between free-living and host habitats. Here, we used the bioluminescent squid and fish symbiont Vibrio fischeri to probe for host and environmental conditions that control interbacterial competition via the type VI secretion system. Our findings identify a new host-specific cue that promotes competition among many but not all V. fischeri isolates, underscoring the utility of studying multiple strains to reveal how competitive mechanisms may be differentially regulated among closely related populations as they evolve to fill distinct niches.
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A lasting symbiosis: how Vibrio fischeri finds a squid partner and persists within its natural host. Nat Rev Microbiol 2021; 19:654-665. [PMID: 34089008 DOI: 10.1038/s41579-021-00557-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2021] [Indexed: 01/10/2023]
Abstract
As our understanding of the human microbiome progresses, so does the need for natural experimental animal models that promote a mechanistic understanding of beneficial microorganism-host interactions. Years of research into the exclusive symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium Vibrio fischeri have permitted a detailed understanding of those bacterial genes underlying signal exchange and rhythmic activities that result in a persistent, beneficial association, as well as glimpses into the evolution of symbiotic competence. Migrating from the ambient seawater to regions deep inside the light-emitting organ of the squid, V. fischeri experiences, recognizes and adjusts to the changing environmental conditions. Here, we review key advances over the past 15 years that are deepening our understanding of these events.
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Multiplexed Competition in a Synthetic Squid Light Organ Microbiome Using Barcode-Tagged Gene Deletions. mSystems 2020; 5:5/6/e00846-20. [PMID: 33323415 PMCID: PMC7771539 DOI: 10.1128/msystems.00846-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Beneficial microbes play essential roles in the health and development of their hosts. However, the complexity of animal microbiomes and general genetic intractability of their symbionts have made it difficult to study the coevolved mechanisms for establishing and maintaining specificity at the microbe-animal host interface. Beneficial symbioses between microbes and their eukaryotic hosts are ubiquitous and have widespread impacts on host health and development. The binary symbiosis between the bioluminescent bacterium Vibrio fischeri and its squid host Euprymna scolopes serves as a model system to study molecular mechanisms at the microbe-animal interface. To identify colonization factors in this system, our lab previously conducted a global transposon insertion sequencing (INSeq) screen and identified over 300 putative novel squid colonization factors in V. fischeri. To pursue mechanistic studies on these candidate genes, we present an approach to quickly generate barcode-tagged gene deletions and perform high-throughput squid competition experiments with detection of the proportion of each strain in the mixture by barcode sequencing (BarSeq). Our deletion approach improves on previous techniques based on splicing by overlap extension PCR (SOE-PCR) and tfoX-based natural transformation by incorporating a randomized barcode that results in unique DNA sequences within each deletion scar. Amplicon sequencing of the pool of barcoded strains before and after colonization faithfully reports on known colonization factors and provides increased sensitivity over colony counting methods. BarSeq enables rapid and sensitive characterization of the molecular factors involved in establishing the Vibrio-squid symbiosis and provides a valuable tool to interrogate the molecular dialogue at microbe-animal host interfaces. IMPORTANCE Beneficial microbes play essential roles in the health and development of their hosts. However, the complexity of animal microbiomes and general genetic intractability of their symbionts have made it difficult to study the coevolved mechanisms for establishing and maintaining specificity at the microbe-animal host interface. Model symbioses are therefore invaluable for studying the mechanisms of beneficial microbe-host interactions. Here, we present a combined barcode-tagged deletion and BarSeq approach to interrogate the molecular dialogue that ensures specific and reproducible colonization of the Hawaiian bobtail squid by Vibrio fischeri. The ability to precisely manipulate the bacterial genome, combined with multiplex colonization assays, will accelerate the use of this valuable model system for mechanistic studies of how environmental microbes—both beneficial and pathogenic—colonize specific animal hosts.
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