Raphidophyceae (Raphidophyta)

Horiguchi, Takeo

doi:10.1007/978-3-319-32669-6_37-1

Cited by 4 publications

(4 citation statements)

References 92 publications

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“…Raphidophytes are eukaryotic, unicellular algae belonging to the chromalveolates. In particular, the marine species Heterosigma akashiwo and Chattonella subsalsa have received much scientific attention as they form harmful algal blooms and can cause extensive fish kills [3]. However, the freshwater species, such as Gonyostomum semen and Vacuolaria virescens , have been often overlooked and are less studied due to their lack of toxins.…”

Section: Introductionmentioning

confidence: 99%

Sequencing and Phylogenetic Analysis of Chloroplast Genes in Freshwater Raphidophytes

Sassenhagen

Rengefors

2019

Genes

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The complex evolution of chloroplasts in microalgae has resulted in highly diverse pigment profiles. Freshwater raphidophytes, for example, display a very different pigment composition to marine raphidophytes. To investigate potential differences in the evolutionary origin of chloroplasts in these two groups of raphidophytes, the plastid genomes of the freshwater species Gonyostomum semen and Vacuolaria virescens were sequenced. To exclusively sequence the organelle genomes, chloroplasts were manually isolated and amplified using single-cell whole-genome-amplification. Assembled and annotated chloroplast genes of the two species were phylogenetically compared to the marine raphidophyte Heterosigma akashiwo and other evolutionarily more diverse microalgae. These phylogenetic comparisons confirmed the high relatedness of all investigated raphidophyte species despite their large differences in pigment composition. Notable differences regarding the presence of light-independent protochlorophyllide oxidoreductase (LIPOR) genes among raphidophyte algae were also revealed in this study. The whole-genome amplification approach proved to be useful for isolation of chloroplast DNA from nuclear DNA. Although only approximately 50% of the genomes were covered, this was sufficient for a multiple gene phylogeny representing large parts of the chloroplast genes.

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Section: Introductionmentioning

confidence: 99%

Sequencing and Phylogenetic Analysis of Chloroplast Genes in Freshwater Raphidophytes

Sassenhagen

Rengefors

2019

Genes

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“…Raphidophyceae is a small group of microalgae that includes widely distributed marine and freshwater representatives (Horiguchi ). Taxonomic identification of raphidophytes based only on morphological traits is frequently difficult because cells are usually very sensitive, easily losing their original shape during fixation (Throndsen ; Hargraves & Maranda ).…”

Section: Introductionmentioning

confidence: 99%

Morphological and genetic characterization of bloom‐forming Raphidophyceae from Brazilian coast

Branco

Almeida

Alves‐de‐Souza

et al. 2019

Phycological Research

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SUMMARY Massive fish kills caused by bloom‐forming species of the Raphidophyceae occur in many marine coastal areas and often cause significant economic losses. The ultrastructure and phylogeny of marine raphidophytes from the Brazilian coast have not been fully analyzed. Here, we present the first combined morphological and genetic characterization of raphidophyte strains from the Brazilian coast. Ten strains of four raphidophyte species (Chattonella subsalsa, C. antiqua, Heterosigma akashiwo, and Fibrocapsa japonica) were characterized based on morphology (including ultrastructure) and LSU rDNA sequences. Chattonella subsalsa and C. antiqua formed two distinct genetic clades. We found that the cell size is the only phenotypic feature separating C. subsalsa and C. antiqua strains from Brazil, whereas traditional characteristics used for species separation in the genus Chattonella (i.e., tail size, chloroplast presence in the tail, ‘oboe‐shaped’ mucocysts, and presence of thylakoids in the pyrenoid matrix) were not sufficiently discriminative, due to their overlapping in the two taxa. The phylogenetic analysis indicated intra‐specific geographic differences among C. subsalsa sequences, with two subclades: one formed by isolates from Brazil, USA, and Iran, and another by a sequence from the Adriatic Sea (Italy). Fibrocapsa japonica also showed intra‐specific geographic differences, with a sequence from a Brazilian strain grouped with strains from Japan, Australia, and Germany, all of them distinct from the Italian isolates. This is the first combined morphological and phylogenetic analysis of raphidophytes from the South Atlantic. Our findings broaden knowledge of the biodiversity of this important bloom‐forming algal group.

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“…We note that mucus production is a common thread throughout the classes belonging to the SI clade. The Raphidophyceae produce mucocysts (for review, see Horiguichi ), the Aurearenophyceae and Chrysoparodoxophyceae extrude gels to anchor cells on their sandy habitats (Kai et al. , Wetherbee et al.…”

Section: Discussionmentioning

confidence: 99%

Further investigations on the PHAEOTHAMNIOPHYCEAE using a multigene phylogeny, with descriptions of five new species

Graf

Yang

Boo

et al. 2019

Journal of Phycology

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We examined 12 strains representing eight species classified in the algal class Phaeothamniophyceae (Heterokontophyta). Based upon a five‐gene molecular phylogeny (nuclear‐encoded SSU rRNA and plastid‐encoded psaA, psbA, psbC, and rbcL) and light microscopic observations, we describe five new species: Phaeoschizochlamys santosii sp. nov., Phaeoschizochlamys siveri sp. nov., Phaeothamnion wetherbeei sp. nov., Stichogloea dopii sp. nov. and Stichogloea fawleyi sp. nov. The Phaeothamniophyceae, as delimited here, form a natural group that is sister to the Aurearenophyceae. Molecular phylogenetic analyses proved more reliable than morphological characters for distinguishing species. Evolutionary trends with the SI clade of the heterokont algae are discussed.

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Raphidophyceae (Raphidophyta)

Cited by 4 publications

References 92 publications

Sequencing and Phylogenetic Analysis of Chloroplast Genes in Freshwater Raphidophytes

Sequencing and Phylogenetic Analysis of Chloroplast Genes in Freshwater Raphidophytes

Morphological and genetic characterization of bloom‐forming Raphidophyceae from Brazilian coast

Further investigations on the PHAEOTHAMNIOPHYCEAE using a multigene phylogeny, with descriptions of five new species

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