title: The chimerical and multifaceted marine acoel Symsagittifera roscoffensis: from photosymbiosis to brain regeneration.
abstract: A remarkable example of biological engineering is the capability of some marine animals to take advantage of photosynthesis by hosting symbiotic algae. This capacity, referred to as photosymbiosis, is based on structural and functional complexes that involve two distantly unrelated organisms. These stable photosymbiotic associations between metazoans and photosynthetic protists play fundamental roles in marine ecology as exemplified by reef communities and their vulnerability to global changes threats. Here we introduce a photosymbiotic tidal acoel flatworm, Symsagittifera roscoffensis, and its obligatory green algal photosymbiont, Tetraselmis convolutae (Lack of the algal partner invariably results in acoel lethality emphasizing the mandatory nature of the photosymbiotic algae for the animal's survival). Together they form a composite photosymbiotic unit, which can be reared in controlled conditions that provide easy access to key life-cycle events ranging from early embryogenesis through the induction of photosymbiosis in aposymbiotic juveniles to the emergence of a functional "solar-powered" mature stage. Since it is possible to grow both algae and host under precisely controlled culture conditions, it is now possible to design a range of new experimental protocols that address the mechanisms and evolution of photosymbiosis. S. roscoffensis thus represents an emerging model system with experimental advantages that complement those of other photosymbiotic species, in particular corals. The basal taxonomic position of S. roscoffensis (and acoels in general) also makes it a relevant model for evolutionary studies of development, stem cell biology and regeneration. Finally, it's autotrophic lifestyle and lack of calcification make S. roscoffensis a favorable system to study the role of symbiosis in the response of marine organisms to climate change (e.g., ocean warming and acidification). In this article we summarize the state of knowledge of the biology of S. roscoffensis and its algal partner from studies dating back over a century, and provide an overview of ongoing research efforts that take advantage of this unique system.
authors.affiliation: Université Pierre et Marie Curie -CNRS, FR2424, Functional Exploration in Marine Model Organisms - Centre de Ressources Biologiques Marines, Station Biologique de Roscoff Roscoff, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Bailly
authors.affiliation: Université Pierre et Marie Curie -CNRS, FR2424, Functional Exploration in Marine Model Organisms - Centre de Ressources Biologiques Marines, Station Biologique de Roscoff Roscoff, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Laguerre
authors.affiliation: Université Pierre et Marie Curie -CNRS, UMR 7139, Marine Plants and Biomolecules, Station Biologique de Roscoff Roscoff, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Correc
authors.affiliation: Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Sciences - Kristineberg, University of Gothenburg - Fiskebäckskil Sweden.
authors.forename: Sam
authors.initials: S
authors.lastname: Dupont
authors.affiliation: TU Dresden, DFG-Research Center for Regenerative Therapies Dresden Dresden, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kurth
authors.affiliation: TU Dresden, DFG-Research Center for Regenerative Therapies Dresden Dresden, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Pfannkuchen
authors.affiliation: Institute of Zoology, Technical University Dresden Dresden, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Entzeroth
authors.affiliation: Université Pierre et Marie Curie -CNRS, FR2424, RCC (Roscoff Culture Collection) - Centre de Ressources Biologiques Marines, Station Biologique de Roscoff Roscoff, France.
authors.forename: Ian
authors.initials: I
authors.lastname: Probert
authors.affiliation: Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine Detroit, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Vinogradov
authors.affiliation: INSERM, UMR S 968, CNRS/Université Pierre et Marie Curie - Institut de la Vision/Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts Paris, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Lechauve
authors.affiliation: CNRS UMR 7144 and Université Pierre and Marie Curie, EPEP - Evolution of Protists and Pelagic Ecosystems, Station Biologique de Roscoff Roscoff, France.
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Garet-Delmas
authors.affiliation: Biozentrum, University of Basel Basel, Switzerland.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Reichert
authors.affiliation: Department of Molecular Cell and Developmental Biology, University of California Los Angeles, CA, USA.
authors.forename: Volker
authors.initials: V
authors.lastname: Hartenstein
keywords: acoel; algae; brain; model; regeneration; roscoffensis; symbiosis; tetraselmis