Cyst-motile stage relationship and molecular phylogeny of a new freshwater dinoflagellate Gymnodinium plasticum from Plastic Lake, Canada

Type Article
Date 2017-10
Language English
Author(s) Wang Na1, Luo Zhaohe1, Mertens KennethORCID2, McCarthy Francine M. G.3, Gu Li1, Gu Haifeng1
Affiliation(s) 1 : State Ocean Adm, Inst Oceanog 3, Xiamen, Peoples R China.
2 : IFREMER, Stn Biol Marine, LER BO, Concarneau, France.
3 : Brock Univ, Earth Sci, St Catharines, ON, Canada.
Source Phycological Research (1322-0829) (Wiley), 2017-10 , Vol. 65 , N. 4 , P. 312-321
DOI 10.1111/pre.12190
WOS© Times Cited 3
Keyword(s) apical structure complex, cyst, Gymnodiniales sensu stricto, Gymnodinium fuscum
Abstract

The dinophyceaen genus Gymnodinium was established with the freshwater species G. fuscum as type. According to Thessen et al. (2012), there are 268 species, with the majority marine species. In recently published molecular phylogenies based on ribosomal DNA sequences, Gymnodinium is polyphyletic. Here, a new freshwater Gymnodinium species, G. plasticum, is described from Plastic Lake, Ontario, Canada. Two strains were established by incubating single cysts, and their morphology was examined with light microscopy and scanning electron microscopy. The cyst had a rounded epicyst and hypocyst with a wide cingulum and smooth surface. Vegetative cells were characterized by an elongated nucleus running vertically and a deep sulcal intrusion. The apical structure complex was horseshoe-shaped and consisted of two pronounced ridges with a deep internal groove, encircling 80% of the apex. Small subunit ribosomal DNA (SSU rDNA), large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS) sequences were obtained from cultured strains. Molecular phylogeny based on concatenated SSU, LSU and ITS sequences supports the monophyly of the Gymnodiniales sensu stricto clade but our results suggest that many Gymnodinium species might need reclassification. Gymnodinium plasticum is closest to Dissodinium pseudolunula in our phylogeny but distant from the type species G. fuscum, as are the other gymnodiniacean taxa.

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Wang Na, Luo Zhaohe, Mertens Kenneth, McCarthy Francine M. G., Gu Li, Gu Haifeng (2017). Cyst-motile stage relationship and molecular phylogeny of a new freshwater dinoflagellate Gymnodinium plasticum from Plastic Lake, Canada. Phycological Research, 65(4), 312-321. Publisher's official version : https://doi.org/10.1111/pre.12190 , Open Access version : https://archimer.ifremer.fr/doc/00406/51731/