title: Differential specificity between closely related corals and abundant Endozoicomonas endosymbionts across global scales.
abstract: Reef-building corals are well regarded not only for their obligate association with endosymbiotic algae, but also with prokaryotic symbionts, the specificity of which remains elusive. To identify the central microbial symbionts of corals, their specificity across species and conservation over geographic regions, we sequenced partial SSU ribosomal RNA genes of Bacteria and Archaea from the common corals Stylophora pistillata and Pocillopora verrucosa across 28 reefs within seven major geographical regions. We demonstrate that both corals harbor Endozoicomonas bacteria as their prevalent symbiont. Importantly, catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) with Endozoicomonas-specific probes confirmed their residence as large aggregations deep within coral tissues. Using fine-scale genotyping techniques and single-cell genomics, we demonstrate that P. verrucosa harbors the same Endozoicomonas, whereas S. pistillata associates with geographically distinct genotypes. This specificity may be shaped by the different reproductive strategies of the hosts, potentially uncovering a pattern of symbiont selection that is linked to life history. Spawning corals such as P. verrucosa acquire prokaryotes from the environment. In contrast, brooding corals such as S. pistillata release symbiont-packed planula larvae, which may explain a strong regional signature in their microbiome. Our work contributes to the factors underlying microbiome specificity and adds detail to coral holobiont functioning.
authors.affiliation: Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.|Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Neave
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.
authors.forename: Rita
authors.initials: R
authors.lastname: Rachmawati
authors.affiliation: Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
authors.forename: Liping
authors.initials: L
authors.lastname: Xun
authors.affiliation: Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
authors.forename: Craig T
authors.initials: CT
authors.lastname: Michell
authors.affiliation: Australian Institute of Marine Science and College of Science and Engineering, James Cook University Townsville, Townsville, Queensland, Australia.
authors.forename: David G
authors.initials: DG
authors.lastname: Bourne
authors.affiliation: Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Apprill
authors.affiliation: Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
authors.forename: Christian R
authors.initials: CR
authors.lastname: Voolstra
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000145:classification / Q000382:microbiology*; D057894:Coral Reefs; D020563:Gammaproteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D005838:Genotype; D017404:In Situ Hybridization, Fluorescence; D013559:Symbiosis