Morphological and molecular characterization of the toxic dinoflagellate Ostreopsis cf. ovata (Dinophyta) from Brazil (South Atlantic Ocean)

Abstract

Ostreopsis cf. ovata is a toxic epiphytic dinoflagellate widely distributed in warm waters that often co-occur with species of the genera Coolia, Fukuyoa, Gambierdiscus and Prorocentrum. We investigated a strain isolated from the coast of Ubatuba, Brazil (Southwest Atlantic Ocean) by light and epifluorescence microscopies; we also report molecular data based on the LSU rDNA and ITS markers. Cells were 35-65 µm in the dorso-ventral diameter and 20-40 µm wide. We obtained the sequence of a ~1 900 base pair region of the rRNA gene cistron. In the LSU rDNA phylogeny, the sequences under the names O. ovata and O. cf. ovata branched into three clades. The ITS marker showed greater resolving power and the sequences of O. ovata/O. cf. ovata split into five clades. Our ITS sequence branched in a clade with sequences of strains from the Mediterranean Sea, European Atlantic coasts, subtropical NE Atlantic, other sequences from Brazil at Rio de Janeiro, and a few sequences from Japan. The cell dimensions and thecal plate arrangement were under the variability range reported in other ocean regions. (Norris, Bomber, & Balech, 1985;Quod, 1994;Faust & Morton, 1995;Faust, 1999; Accoroni et al., 2017). Other ecologically related genera such as Gambierdiscus or Coolia have increased the number of species in the last decade, due to the emergence of molecular data. In contrast, the number of species of Ostreopsis has remained static between 1999 and 2016. This situation is attributable to some confusion in the diagnostic characters for the delimitation of the known species due to plasticity in its morphology (see review in Parsons et al., 2012). Schmidt (1901) described O. siamensis based on two illustrations, elongated and round cells. Fukuyo (1981) re-described O. siamensis and ascribed it to Schmidt's round cell, and the elongated cells were described as the new species O. lenticularis (Fukuyo, 1981). Ostreopsis lenticularis was distinguished from O. siamensis by lacking body undulation and having fine pores densely scattered on the thecal plates in addition to the larger pores found on both species. Fukuyo (1981) also described O. ovata as distinguishable from the other two species by having a more ovoid shape and smaller size. These diagnostic characters are not stable and the lack of genetic data for the holotype specimens lead to the use of these names as O. cf. ovata or O. cf. siamensis until accurate morphological data and genetic sequences gathered from the type localities re-defines each species (Penna et al., 2005(Penna et al., , 2010. Sequences of several strains O. cf. ovata isolated in 2000 in a single location at Rio de Janeiro, Brazil, branched with sequences from the Mediterranean Sea and the temperate and subtropical NE Atlantic at Madeira and Canary Islands, confirming the wide distribution of this species (Penna et al., 2005(Penna et al., , 2010David, Laza-Martínez, Miguel, & Orive, 2013). Nascimento, França, Gonçalves, and Ferreira (2012b) and Nascimento, Corrêa, Menezes, Varela, Paredes, and Morris...

Ostreopsis cf. ovata (Dinophyceae) Molecular Phylogeny, Morphology, and Detection of Ovatoxins in Strains and Field Samples from Brazil

“…ovata was registered by morphological identification at several places along the Brazilian coast and the oceanic islands (e.g., at Saint Pauls' Rocks, Nascimento et al [29]) within latitudes ranging from 27 • 35 S to 05 • 5 N. Molecular sequences of O. cf. ovata have been retrieved from Rio de Janeiro [10,26], Ubatuba, São Paulo [35], Salvador, Bahia [47], and Currais archipelago at Paraná [30]. The current study includes new molecular sequences from Mata de São João at Bahia, Tibaú do Sul at Rio Grande do Norte, and the oceanic archipelago of Fernando de Noronha.…”

A Review on the Biodiversity and Biogeography of Toxigenic Benthic Marine Dinoflagellates of the Coasts of Latin America

“…Ostreopsis O. lenticularis Tosteson et al, 1986 Bahamas Coolia C. santacroce Dominican Republic Coolia C. palmyrensis C. malayensis British and United States Virgin Islands Coolia C. santacroce C. malayensis Carlson and Tindall, 1985;Litaker et al, 2009;Rains and Parsons, 2015 (Continued) Faust, 1990aFaust, ,b, 1993cFaust, ,d, 1994Faust, , 1995Faust, , 1996Faust, , 1997Faust, , 1999Faust, , 2000Faust, , 2004Faust and Gulledge, 1996;Morton and Faust, 1997;Faust and Steidinger, 1998;Faust et al, 2008;Litaker et al, 2009 Okolodkov et al, 2007Okolodkov et al, , 2009Barón-Campis et al, 2014;Okolodkov et al, 2014;Martínez-Cruz et al, 2016;Estrada-Vargas et al, 2017 Florida Mitchell, 1985;Bomber et al, 1988Bomber et al, , 1989Litaker et al, 2010 Southwestern Atlantic Brazil Ostreopsis O. cf. ovata Prorocentrum P. caipirignum Gómez et al, 2017b;Nascimento et al, 2017 Species recognized as toxigenic were compiled from the IOC-Harmful Microalgal Species list (Moestrup et al, 2009) (Sierra-Beltrán et al, 1998;Núñez-Vázquez et al, 2000;Cortés-Lara et al, 2005;Gárate-Lizárraga, 2005;Núñez-Vázquez, 2005;Okolodkov and Gárate-Lizárraga, 2006). The latter species was also reported from Isabel Island, Nayarit, 70 km from the mainland <...>…”

“…Along the Brazilian coasts, Ostreopsis cf. ovata and Coolia malayensis were reported in the coastal waters of Ubatuba, east of São Paulo (Gómez et al, 2017b). A new toxic epiphytic species, Prorocentrum caipirignum, was described (Nascimento et al, 2017) from isolates collected from Rio de Janeiro (Arraial do Cabo) and Bahía (Garapuá, Ilha de Tinharé, Cairu).…”

Effects of the toxic dinoflagellates Prorocentrum lima and Ostreopsis cf. ovata on immune responses of cultured oysters Crassostrea gasar

“…O. cf. ovata was found in the states of Rio Grande do Norte, Bahia, Rio de Janeiro, São Paulo, Paraná, and in the oceanic islands of Fernando de Noronha, Trindade, and São Pedro and São Paulo Archipelago (Gómez et al, 2017;Nascimento et al, 2020;Tibiriçá et al, 2019).…”