title: Development and Symbiosis Establishment in the Cnidarian Endosymbiosis Model Aiptasia sp.
abstract: Symbiosis between photosynthetic algae and heterotrophic organisms is widespread. One prominent example of high ecological relevance is the endosymbiosis between dinoflagellate algae of the genus Symbiodinium and reef-building corals, which typically acquire symbionts anew each generation during larval stages. The tropical sea anemone Aiptasia sp. is a laboratory model system for this endosymbiosis and, similar to corals, produces non-symbiotic larvae that establish symbiosis by phagocytosing Symbiodinium from the environment into the endoderm. Here we generate the first overview of Aiptasia embryogenesis and larval development and establish in situ hybridization to analyze expression patterns of key early developmental regulators. Next, we quantify morphological changes in developing larvae and find a substantial enlargement of the gastric cavity over time. Symbiont acquisition starts soon after mouth formation and symbionts occupy a major portion of the host cell in which they reside. During the first 14 days of development, infection efficiency remains constant while in contrast, localization of phagocytosed symbionts changes, indicating that the occurrence of functional phagocytosing cells may be developmentally regulated. Taken together, here we provide the essential framework to further develop Aiptasia as a model system for the analysis of symbiosis establishment in cnidarian larvae at the molecular level.
authors.affiliation: Centre for Organismal Studies (COS), Heidelberg University, Heidelberg 69120, Germany.
authors.forename: Madeline
authors.initials: M
authors.lastname: Bucher
authors.affiliation: Centre for Organismal Studies (COS), Heidelberg University, Heidelberg 69120, Germany.|Graduate Program in Areas of Basic and Applied Biology (GABBA), University of Porto, Porto 4200-465, Portugal.
authors.forename: Iliona
authors.initials: I
authors.lastname: Wolfowicz
authors.affiliation: Centre for Organismal Studies (COS), Heidelberg University, Heidelberg 69120, Germany.
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Voss
authors.affiliation: Centre for Organismal Studies (COS), Heidelberg University, Heidelberg 69120, Germany.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Hambleton
authors.affiliation: Centre for Organismal Studies (COS), Heidelberg University, Heidelberg 69120, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Guse
mesh_terms: D000818:Animals; D003063:Cnidaria / Q000502:physiology; D057894:Coral Reefs; D004141:Dinoflagellida / Q000502:physiology; D047108:Embryonic Development / Q000502:physiology; D007814:Larva / Q000254:growth & development; D008954:Models, Biological; D010788:Photosynthesis / Q000502:physiology; D012615:Sea Anemones / Q000196:embryology*; D013559:Symbiosis / Q000502:physiology*