An updated assessment of Symbiodinium spp. that associate with common scleractinian corals from Moorea (French Polynesia) reveals high diversity among background symbionts and a novel finding of clade B

Héloïse H Rouzé (1) , Gaël Lecellier (2, 1, 3) , Denis Saulnier (2) , Serge Planes (1) , Yannick H Gueguen (4) , Herman H Wirshing (5) , Véronique Berteaux-Lecellier (2, 1)

1 CRIOBE - Centre de recherches insulaires et observatoire de l'environnement
2 LabEX CORAIL - Laboratoire d'Excellence CORAIL
3 Université Paris-Saclay
4 IHPE - Interactions Hôtes-Pathogènes-Environnements
5 Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington

The adaptative bleaching hypothesis (ABH) states that, depending on the symbiotic flexibility of coral hosts (i.e., the ability of corals to ''switch'' or ''shuffle'' their algal symbionts), coral bleaching can lead to a change in the composition of their associated Symbiodinium community and, thus, contribute to the coral's overall survival. In order to determine the flexibility of corals, molecular tools are required to provide accurate species delineations and to detect low levels of coral-associated Symbiodinium. Here, we used highly sensitive quantitative (real-time) PCR (qPCR) technology to analyse five common coral species from Moorea (French Polynesia), previously screened using only traditional molecular methods, to assess the presence of low-abundance (background) Symbiodinium spp. Similar to other studies, each coral species exhibited a strong specificity to a particular clade, irrespective of the environment. In addition, however, each of the five species harboured at least one additional Symbiodinium clade, among clades A–D, at background levels. Unexpectedly, and for the first time in French Polynesia, clade B was detected as a coral symbiont. These results increase the number of known coral-Symbiodinium associations from corals found in French Polynesia, and likely indicate an underestimation of the ability of the corals in this region to associate with and/or ''shuffle'' different Symbiodinium clades. Altogether our data suggest that corals from French Polynesia may favor a trade-off between optimizing symbioses with a specific Symbiodinium clade(s), maintaining associations with particular background clades that may play a role in the ability of corals to respond to environmental change. How to cite this article Rouzé et al. (2017), An updated assessment of Symbiodinium spp. that associate with common scleractinian corals from Moorea (French Polynesia) reveals high diversity among background symbionts and a novel finding of clade B.

Mots clés: Corals; French polynesia; Clade B; Symbiodinium; qPCR; Flexibility; Generalist; Faithful clade

Domaines: Biodiversité et Ecologie

Héloïse H Rouzé, Gaël Lecellier, Denis Saulnier, Serge Planes, Yannick H Gueguen, et al.. An updated assessment of Symbiodinium spp. that associate with common scleractinian corals from Moorea (French Polynesia) reveals high diversity among background symbionts and a novel finding of clade B. PeerJ, 2017, 5, pp.e2856. ⟨10.7717/peerj.2856⟩. ⟨hal-01430294⟩