Editing Coral (section)

===Holobionts===
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Reef-building corals are well-studied [[holobiont]]s that include the coral itself together with its symbiont [[zooxanthellae]] (photosynthetic dinoflagellates), as well as its associated bacteria and viruses.<ref name="Knowlton2003">Knowlton, N. and Rohwer, F. (2003) "Multispecies microbial mutualisms on coral reefs: the host as a habitat". ''The American Naturalist'', '''162'''(S4): S51-S62. {{doi|10.1086/378684}}.</ref> Co-evolutionary patterns exist for coral microbial communities and coral phylogeny.<ref>{{Cite journal|last1=Pollock|first1=F. Joseph|last2=McMinds|first2=Ryan|last3=Smith|first3=Styles|last4=Bourne|first4=David G.|last5=Willis|first5=Bette L.|last6=Medina|first6=Mónica|last7=Thurber|first7=Rebecca Vega|last8=Zaneveld|first8=Jesse R.|date=2018-11-22|title=Coral-associated bacteria demonstrate phylosymbiosis and cophylogeny|journal=Nature Communications|language=en|volume=9|issue=1|page=4921|bibcode=2018NatCo...9.4921P|doi=10.1038/s41467-018-07275-x|issn=2041-1723|pmc=6250698|pmid=30467310|doi-access=free}}</ref>[[File:Relationships between corals and their microbial symbionts.jpg|thumb|upright=2.4| {{center|Relationships between corals and their microbial [[symbiont]]s<ref>Peixoto, R.S., Rosado, P.M., Leite, D.C.D.A., Rosado, A.S. and Bourne, D.G. (2017) "Beneficial microorganisms for corals (BMC): proposed mechanisms for coral health and resilience". ''Frontiers in Microbiology'', '''8''': 341. {{doi|10.3389/fmicb.2017.00341}}.</ref>}}]]

It is known that the coral's [[microbiome]] and symbiont influence host health, however, the historic influence of each member on others is not well understood. Scleractinian corals have been diversifying for longer than many other symbiotic systems, and their microbiomes are known to be partially species-specific.<ref>{{Cite journal|last1=Apprill|first1=Amy|last2=Weber|first2=Laura G.|last3=Santoro|first3=Alyson E.|title=Distinguishing between Microbial Habitats Unravels Ecological Complexity in Coral Microbiomes|journal=mSystems|year=2016|volume=1|issue=5|pages=e00143–16|doi=10.1128/mSystems.00143-16|pmc=5080407|pmid=27822559}}</ref> It has been suggested that ''[[Endozoicomonas]]'', a commonly highly abundant bacterium in corals, has exhibited [[codiversification]] with its host.<ref>{{Cite journal|last1=La Rivière|first1=Marie|last2=Garrabou|first2=Joaquim|last3=Bally|first3=Marc|date=2015-12-01|title=Evidence for host specificity among dominant bacterial symbionts in temperate gorgonian corals|url=https://doi.org/10.1007/s00338-015-1334-7|journal=Coral Reefs|language=en|volume=34|issue=4|pages=1087–1098|doi=10.1007/s00338-015-1334-7|bibcode=2015CorRe..34.1087L|s2cid=14309443|issn=1432-0975}}</ref><ref>{{Cite journal|last1=van de Water|first1=Jeroen A. J. M.|last2=Melkonian|first2=Rémy|last3=Voolstra|first3=Christian R.|last4=Junca|first4=Howard|last5=Beraud|first5=Eric|last6=Allemand|first6=Denis|last7=Ferrier-Pagès|first7=Christine|date=2017-02-01|title=Comparative Assessment of Mediterranean Gorgonian-Associated Microbial Communities Reveals Conserved Core and Locally Variant Bacteria|url=https://doi.org/10.1007/s00248-016-0858-x|journal=Microbial Ecology|language=en|volume=73|issue=2|pages=466–478|doi=10.1007/s00248-016-0858-x|pmid=27726033|bibcode=2017MicEc..73..466V |s2cid=22336906|issn=1432-184X}}</ref> This hints at an intricate set of relationships between the members of the coral holobiont that have been developing as [[evolution]] of these members occurs.

A study published in 2018<ref>{{Cite journal|last1=Pollock|first1=F. Joseph|last2=McMinds|first2=Ryan|last3=Smith|first3=Styles|last4=Bourne|first4=David G.|last5=Willis|first5=Bette L.|last6=Medina|first6=Mónica|last7=Thurber|first7=Rebecca Vega|last8=Zaneveld|first8=Jesse R.|date=2018-11-22|title=Coral-associated bacteria demonstrate phylosymbiosis and cophylogeny|journal=Nature Communications|language=en|volume=9|issue=1|pages=4921|doi=10.1038/s41467-018-07275-x|pmid=30467310|pmc=6250698|bibcode=2018NatCo...9.4921P|issn=2041-1723}}</ref> revealed evidence of [[phylosymbiosis]] between corals and their tissue and skeleton microbiomes. The coral skeleton, which represents the most diverse of the three coral microbiomes, showed the strongest evidence of phylosymbiosis. Coral microbiome composition and [[Species richness|richness]] were found to reflect coral [[phylogeny]]. For example, interactions between bacterial and eukaryotic coral phylogeny influence the abundance of ''Endozoicomonas'', a highly abundant bacterium in the coral holobiont. However, host-microbial [[cophylogeny]] appears to influence only a subset of coral-associated bacteria.

[[File:Control of the microbiota structure in the coral holobiont.jpg|thumb|upright=2.3|left| {{center|'''Top-down and bottom-up control of microbiota structure in the coral holobiont'''}} Stable microbes may be introduced to the holobiont through horizontal or vertical transmission and persist in ecological niches within the coral polyp where growth (or immigration) rates balance removal pressures from biophysical processes and immune or ecological interactions. Transient microbes enter the holobiont from environmental sources (e.g., seawater, prey items, or suspension feeding) and removal rates exceed growth/immigration rates such that a dynamic and high-diversity microbiota results. Transient and stable populations compete for resources including nutrients, light and space and the outcome of resource-based competition (bottom-up control) ultimately determines population growth rate and thus ability to persist when subject to removal. Whether a population is categorized as stable or transient may depend on the timeframe considered.<ref>Thompson, J.R., Rivera, H.E., Closek, C.J. and Medina, M. (2015) "Microbes in the coral holobiont: partners through evolution, development, and ecological interactions". ''Frontiers in cellular and infection microbiology'', '''4''': 176. {{doi|10.3389/fcimb.2014.00176}}. [[File:CC-BY icon.svg|50px]] Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref><br/>{{space|25}}<small>AMP = antimicrobial peptides, ROS = reactive oxygen species</small>]]

[[File:Trophic connections of the coral holobiont in the planktonic food web.jpg|thumb|upright=1.3|right| {{center|Trophic connections of the coral [[holobiont]] in the planktonic food web<ref>Thompson, J.R., Rivera, H.E., Closek, C.J. and Medina, M. (2015) "Microbes in the coral holobiont: partners through evolution, development, and ecological interactions". ''Frontiers in cellular and infection microbiology'', '''4''': 176. {{doi|10.3389/fcimb.2014.00176}}.</ref>}}]]

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