First Report of the Photosynthetic Dinoflagellate Genus Azadinium in the Pacific Ocean: Morphology and Molecular Characterization of Azadinium cf. poporum
A strain of a dinoflagellate belonging to the genus Azadinium was obtained by the incubation of sediments collected from Shiwha Bay, Korea. This report of the genus Azadinium is the first outside of northern Europe and furthermore from the Pacific Ocean. The diagnostic morphological features of the...
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| Published in: | The Journal of eukaryotic microbiology Vol. 59; no. 2; pp. 145 - 156 |
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| Main Authors: | , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Hoboken, NJ
Blackwell Publishing Ltd
01-03-2012
Wiley |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | A strain of a dinoflagellate belonging to the genus Azadinium was obtained by the incubation of sediments collected from Shiwha Bay, Korea. This report of the genus Azadinium is the first outside of northern Europe and furthermore from the Pacific Ocean. The diagnostic morphological features of the isolate very closely resemble the recently described species Azadinium poporum isolated from the North Sea. However, the shape of the 3′ apical plate and the occasional morphological variations unreported from A. poporum bring minor distinctions between strains from different locations. The DNA sequences of small subunit, ITS, and large subunit (LSU) rDNA differed by 0.2%, 2.6%, and 3.6%, respectively, from those of A. poporum, whereas the COI gene was identical to those found in all strains of Azadinium. Phylogenetic analyses of the ribosomal DNA regions generally positioned the Korean strain as a sister taxon of A. poporum. However, the Korean isolate tends to occupy a basal position within Azadinium species with ITS rDNA and LSU rDNA. Using liquid chromatography coupled with tandem mass spectrometry, no known azaspiracids were detected. The slight but discernible morphological differences, the distinct rDNA sequences, and the tendency of the Korean strain to diverge phylogenetically based on ITS rDNA and LSU rDNA from A. poporum do not enable us to clearly assign the isolate to A. poporum. However, these characteristics do not allow us to classify it as a distinct species, and it is therefore designated as Azadinium cf. poporum. The examination of more strains to find more diagnostic characteristics might enable the attribution of this material to a well‐defined taxonomic position. |
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| Bibliography: | Fig. S1-4. Diagrammatic illustrations of thecal plates of Azadinium cf. poporum. S1. Ventral view. S2. Left-lateral view. S3. Dorsal view. S4. Right-lateral view. Disposition of small pores is based on individual cells and does not represent an average distribution. A group of small pores on plate 2″″ was however often observed and is illustrated here. Abbreviations: Sa, anterior sulcal plate; Sd, right sulcal plate; Ss, left sulcal plate; Sm, median sulcal plate; Sp, posterior sulcal plate.Fig. S5. Maximum likelihood (ML) phylogenetic tree based on 1,080 aligned nucleotides of the nuclear SSU rDNA using the GTR + I + G model with Oxyrrhis marina as outgroup taxa. Alignment length includes gaps. The parameters were as follows: assumed nucleotide frequencies A = 0.2819, C = 0.1741, G = 0.2551, and T = 0.2890; substitution rate matrix with G-T = 1.0000, A-C = 0.8776, A-G = 4.0977, A-T = 1.3425, C-G = 0.6189, C-T = 10.2177; proportion of invariable sites = 0.4176 and rates for variable sites assumed to follow a gamma distribution with shape parameter = 0.5438. The numbers at the nodes of the branches indicate the ML bootstrap (left) and Bayesian posterior probability (right) values; only values ≥ 50% or 0.5 are shown.Fig. S6. Maximum likelihood (ML) phylogenetic tree based on 604 aligned nucleotides of the nuclear ITS rDNA using the K81uf + G model with Prorocentrum minimum as outgroup taxa. Alignment length includes gaps. The parameters were as follows: assumed nucleotide frequencies A = 0.2065, C = 0.2489, G = 0.2469, and T = 0.2976; substitution rate matrix with G-T = 1.0000, A-C = 1.0000, A-G = 2.6949, A-T = 0.3832, C-G = 0.3832, C-T = 2.6949; proportion of invariable sites = 0 and rates for variable sites assumed to follow a gamma distribution with shape parameter = 0.3807. The numbers at the nodes of the branches indicate the ML bootstrap (left) and Bayesian posterior probability (right) values; only values ≥ 50% or 0.5 are shown.Fig. S7. Maximum likelihood (ML) phylogenetic tree based on 459 aligned nucleotides of the nuclear LSU rDNA using the GTR + I + G model with Oxyrrhis marina as outgroup taxa. Alignment length includes gaps. The parameters were as follows: assumed nucleotide frequencies A = 0.2337, C = 0.1959, G = 0.2728, and T = 0.2977; substitution rate matrix with G-T = 1.0000, A-C = 0.6504, A-G = 2.2359, A-T = 0.7607, C-G = 0.5000, C-T = 4.9494; proportion of sites assumed to be invariable = 0.1178 and rates for variable sites assumed to follow a gamma distribution with shape parameter = 0.8072. The numbers at the nodes of the branches indicate the ML bootstrap (left) and Bayesian posterior probability (right) values; only values ≥ 50% or 0.5 are shown. Quebec Nature and Technology Research Fund istex:6D2573C67AA34A07B0B0E4335B13514D81620847 Ecological Disturbance Program of KIMST ark:/67375/WNG-3DPV1M5H-B National Research Foundation of Korea Grant - No. NRF-C1ABA001-2010-0020700 ArticleID:JEU600 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 1066-5234 1550-7408 |
| DOI: | 10.1111/j.1550-7408.2011.00600.x |