title: Species-specific viromes in the ancestral holobiont Hydra.
abstract: Recent evidence showing host specificity of colonizing bacteria supports the view that multicellular organisms are holobionts comprised of the macroscopic host in synergistic interdependence with a heterogeneous and host-specific microbial community. Whereas host-bacteria interactions have been extensively investigated, comparatively little is known about host-virus interactions and viral contribution to the holobiont. We sought to determine the viral communities associating with different Hydra species, whether these viral communities were altered with environmental stress, and whether these viruses affect the Hydra-associated holobiont. Here we show that each species of Hydra harbors a diverse host-associated virome. Primary viral families associated with Hydra are Myoviridae, Siphoviridae, Inoviridae, and Herpesviridae. Most Hydra-associated viruses are bacteriophages, a reflection of their involvement in the holobiont. Changes in environmental conditions alter the associated virome, increase viral diversity, and affect the metabolism of the holobiont. The specificity and dynamics of the virome point to potential viral involvement in regulating microbial associations in the Hydra holobiont. While viruses are generally regarded as pathogenic agents, our study suggests an evolutionary conserved ability of viruses to function as holobiont regulators and, therefore, constitutes an emerging paradigm shift in host-microbe interactions.
authors.affiliation: Department of Biology, San Diego State University, San Diego, California, United States of America; Zoological Institute, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: Juris A
authors.initials: JA
authors.lastname: Grasis
authors.affiliation: Zoological Institute, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Lachnit
authors.affiliation: Zoological Institute, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Anton-Erxleben
authors.affiliation: Department of Biology, San Diego State University, San Diego, California, United States of America.
authors.forename: Yan Wei
authors.initials: YW
authors.lastname: Lim
authors.affiliation: Department of Biology, San Diego State University, San Diego, California, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Schmieder
authors.affiliation: Zoological Institute, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Fraune
authors.affiliation: Zoological Institute, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: Sören
authors.initials: S
authors.lastname: Franzenburg
authors.affiliation: Zoological Institute, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: Santiago
authors.initials: S
authors.lastname: Insua
authors.affiliation: Institute of Clinical Molecular Biology, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: GloriaMay
authors.initials: G
authors.lastname: Machado
authors.affiliation: Department of Biology, San Diego State University, San Diego, California, United States of America.
authors.forename: Matthew
authors.initials: M
authors.lastname: Haynes
authors.affiliation: Department of Biology, San Diego State University, San Diego, California, United States of America.
authors.forename: Mark
authors.initials: M
authors.lastname: Little
authors.affiliation: Department of Biology, San Diego State University, San Diego, California, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Kimble
authors.affiliation: Institute of Clinical Molecular Biology, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: Philip
authors.initials: P
authors.lastname: Rosenstiel
authors.affiliation: Department of Biology, San Diego State University, San Diego, California, United States of America.
authors.forename: Forest L
authors.initials: FL
authors.lastname: Rohwer
authors.affiliation: Zoological Institute, Christian-Albrechts University Kiel, Kiel, Germany.
authors.forename: Thomas C G
authors.initials: TC
authors.lastname: Bosch
mesh_terms: D000818:Animals; D001419:Bacteria / Q000302:isolation & purification / Q000821:virology; D001435:Bacteriophages / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D006829:Hydra / Q000378:metabolism / Q000382:microbiology / Q000648:ultrastructure / Q000821:virology*; D015203:Reproducibility of Results; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013559:Symbiosis; D014780:Viruses / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*