Ostreopsis lenticularis Y. Fukuyo (Dinophyceae, Gonyaulacales) from French Polynesia (South Pacific Ocean): A revisit of its morphology, molecular phylogeny and toxicity

Type Article
Date 2019-04
Language English
Author(s) Chomérat NicolasORCID1, Bilien GwenaelORCID1, Derrien AmelieORCID1, Henry Kévin2, Ung André2, Viallon Jérôme2, Darius Hélène Taiana2, Mahana Iti Gatti Clémence2, Roué Mélanie3, Hervé FabienneORCID4, Réveillon DamienORCID4, Amzil ZouherORCID4, Chinain Mireille2
Affiliation(s) 1 : Ifremer, LER BO, Station of Marine Biology of Concarneau, Place de la Croix, F-29900, Concarneau, France
2 : Institut Louis Malardé, Laboratoire des Micro-algues toxiques, UMR 241-EIO, PO box 30, 98713, Papeete, Tahiti, French Polynesia
3 : Institut de Recherche pour le Développement (IRD), UMR 241-EIO, PO box 529, 98713, Papeete, Tahiti, French Polynesia
4 : Ifremer, Phycotoxins Laboratory, BP 21105, F-44311, Nantes Cedex 3, France
Source Harmful Algae (1568-9883) (Elsevier BV), 2019-04 , Vol. 84 , P. 95-111
DOI 10.1016/j.hal.2019.02.004
WOS© Times Cited 27
Keyword(s) ITS-5.8S rDNA, LSU rDNA, Microscopy, Ostreopsis lenticularis, Taxonomy, Toxins

To date, the genus Ostreopsis comprises eleven described species, of which seven are toxigenic and produce various compounds presenting a major threat to human and environmental health. The taxonomy of several of these species however remains controversial, as it was based mostly on morphological descriptions leading, in some cases, to ambiguous interpretations and even possible misidentifications. The species Ostreopsis lenticularis was first described by Y. Fukuyo from French Polynesia using light microscopy observations, but without genetic information associated. The present study aims at revisiting the morphology, molecular phylogeny and toxicity of O. lenticularis based on the analysis of 47 strains isolated from 4 distinct locales of French Polynesia, namely the Society, Australes, Marquesas and Gambier archipelagos. Observations in light, epifluorescence and field emission scanning electron microscopy of several of these strains analyzed revealed morphological features in perfect agreement with the original description of O. lenticularis. Cells were oval, not undulated, 60.5–94.4 μm in dorso-ventral length, 56.1–78.2 μm in width, and possessed a typical plate pattern with thecal plates showing two sizes of pores. Phylogenetic analyses inferred from the LSU rDNA and ITS–5.8S sequences revealed that the 47 strains correspond to a single genotype, clustering with a strong support with sequences previously ascribed to Ostreopsis sp. 5. Clonal cultures of O. lenticularis were also established and further tested for their toxicity using the neuroblastoma cell-based assay and LCMS/MS analyses. None of the 19 strains tested showed toxic activity on neuroblastoma cells, while LCMS/MS analyses performed on the strains from Tahiti Island (i.e. type locality) confirmed that palytoxin and related structural analogs were below the detection limit. These findings allow to clarify unambiguously the genetic identity of O. lenticularis while confirming previous results from the Western Pacific which indicate that this species shows no toxicity, thus stressing the need to reconsider its current classification within the group of toxic species.

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Chomérat Nicolas, Bilien Gwenael, Derrien Amelie, Henry Kévin, Ung André, Viallon Jérôme, Darius Hélène Taiana, Mahana Iti Gatti Clémence, Roué Mélanie, Hervé Fabienne, Réveillon Damien, Amzil Zouher, Chinain Mireille (2019). Ostreopsis lenticularis Y. Fukuyo (Dinophyceae, Gonyaulacales) from French Polynesia (South Pacific Ocean): A revisit of its morphology, molecular phylogeny and toxicity. Harmful Algae, 84, 95-111. Publisher's official version : https://doi.org/10.1016/j.hal.2019.02.004 , Open Access version : https://archimer.ifremer.fr/doc/00486/59747/