Morphology, molecular phylogeny and toxinology of Coolia and Prorocentrum strains isolated from the tropical South Western Atlantic Ocean

Abstract

The morphology, molecular phylogeny and toxinology of two Coolia and one Prorocentrum dinoflagellate strains from Brazil were characterized. They matched with Coolia malayensis and Coolia tropicalis morphotypes, while the Prorocentrum strain fitted well with the morphology of Prorocentrum emarginatum. Complementary identification by molecular analyses was carried out based on LSU and ITS-5.8S rDNA. Phylogenetic analyses of Coolia strains (D1/D2 region, LSU rDNA), showed that C. malayensis (strain UFBA044) segregated together with sequences of this species from other parts of the world, but diverged earlier in a separate branch to sequences from São Paulo (Brazil) or Caribbean areas. Coolia tropicalis (strain UFBA055) grouped with other sequences of this species, in a subclade with an isolate from Belize, closer to a subgroup including isolates from Thailand, Australia and Hong Kong. Phylogenetic analyses (ITS-5.8S rDNA) of P. emarginatum (strain UFBA033) grouped together with another sequence of this species from China Sea. Diarrhetic shellfish poisoning toxins (OA, DTXs and PTX2) were not detected in P. emarginatum by mass spectrometry analyses. However, hemolytic assays in P. emarginatum and both Coolia strains in this study showed positive results