• ALGAE
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• v.38 no.4
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• pp.241-252
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• 2023

The genera Carolibrandtia and Chlorella have been described as small green algae with spherical cell shapes that inhabit various environments. Species of these genera are often difficult to identify because of their simple morphology and high phenotypic plasticity. We investigated two small coccoid strains from Antarctica based on morphology, molecular phylogeny by two alignment methods which have been applied to previous phylogenetic studies of the genus Chlorella, and comparison of the secondary structures of nuclear small subunit (SSU) and internal transcribed spacer (ITS) rDNA sequences. Light microscopy of two strains revealed spherical cells containing chloroplasts with pyrenoids, and the morphological characteristics of the strains were nearly identical to those of other Chlorella species. However, based on the phylogenetic analyses of nuclear SSU and ITS rDNA sequences, it was determined that the Antarctic microalgal strains belonged to two genera, as the Chlorella and Carolibrandtia. In addition, the secondary structures of the SSU and ITS2 sequences were analyzed to detect compensatory base changes (CBCs) that were used to identify and describe the two strains. A unique CBC in the SSU rDNA gene was decisive for distinguishing strain CCAP 211/45. The ITS2 rDNA sequences for each strain were compared to those obtained previously from other closely related species. Following the comparison of morphological and molecular characteristics, we propose KSF0092 as a new species, Chlorella terrestris sp. nov., and the reassignment of the strain Chlorella antarctica CCAP 211/45 into Carolibrandtia antarctica comb. nov.

• ALGAE
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• v.20 no.3
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• pp.183-196
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• 2005

Nuclear SSU and ITS1 rDNA and plastid rbcL sequences were determined to identify the seven samples of Porphyra cultivated by means of natural seeding on the southwest coast of Korea and analyzed to access the phylogenetic relationships of them with the natural populations of P. tenera and P. yezoensis from Korea and Japan. SSU, rbcL and ITS1 data from 18, 21 and 31 samples, respectively, including previously published sequences were investigated in the study. Results from our individual and combined data indicated that the seven samples were all P. yezoensis and the entities except one from Muan 2 aquafarm strongly grouped together with the natural populations of P. yezoensis from the south and the west coast of Korea. The sample from Muan 2 seems to be derived from a strain of P. yezoensis introduced from Japan by Porphyra farmers, based on DNA sequence data.

• Ocean Science Journal
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• v.40 no.3
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• pp.155-166
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• 2005

New PCR primers (N=18) were designed for the isolation of complete SSU to LSU rDNA sequences from the dinoflagellate Alexandrium tamarense. Standard PCR, employing each primer set selected for amplifications of less than 1.5 kb, successfully amplified the expected rDNA regions of A. tamarense (Korean isolate, HY970328M). Complete SSU, LSU rDNAs and ITS sequences, including 5.8S rDNA, were recorded at 1,800 bp, 520 bp and 3,393 bp, respectively. The LSU rDNA sequence was the first report in Alexandrium genus. No intron was found in the LSU rRNA coding region. Twelve D-domains within the LSU rDNA were put together into 1,879 bp (44.4% G+C), and cores into 1514 bp (42.8% G+C). The core sequence was significantly different (0.0867 of genetic distance, 91% sequence similarity) in comparison with Prorocentrum micans (GenBank access. no. X16108). The D2 region was the longest in length (300 bp) and highly variable among the 12 D-domains. In a phylogenetic analysis using complete LSU rDNA sequences of a variety of phytoplankton, A. tamarense was clearly separated with high resolution against other species. The result suggests that the sequence may resolve the taxonomic ambiguities of Alexandrium genus, particularly of the tamarensis complex.

• ALGAE
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• v.29 no.2
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• pp.75-99
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• 2014

A small dinoflagellate, Ansanella granifera gen. et sp. nov., was isolated from estuarine and marine waters, and examined by light microscopy, scanning electron microscopy, and transmission electron microscopy. In addition, the identity of the sequences (3,663-bp product) of the small subunit (SSU), internal transcribed spacer (ITS) region (ITS1, 5.8S, ITS2), and D1-D3 large subunit (LSU) rDNA were determined. This newly isolated, thin-walled dinoflagellate has a type E eyespot and a single elongated apical vesicle, and it is closely related to species belonging to the family Suessiaceae. A. granifera has 10-14 horizontal rows of amphiesmal vesicles, comparable to Biecheleria spp. and Biecheleriopsis adriatica, but greater in number than in other species of the family Suessiaceae. Unlike Biecheleria spp. and B. adriatica, A. granifera has grana-like thylakoids. Further, A. granifera lacks a nuclear fibrous connective, which is present in B. adriatica. B. adriatica and A. granifera also show a morphological difference in the shape of the margin of the cingulum. In A. granifera, the cingular margin formed a zigzag line, and in B. adriatica a straight line, especially on the dorsal side of the cell. The episome is conical with a round apex, whereas the hyposome is trapezoidal. Cells growing photosynthetically are $10.0-15.0{\mu}m$ long and $8.5-12.4{\mu}m$ wide. The cingulum is descending, the two ends displaced about its own width. Cells of A. granifera contain 5-8 peripheral chloroplasts, stalked pyrenoids, and a pusule system, but lack nuclear envelope chambers, a nuclear fibrous connective, lamellar body, rhizocysts, and a peduncle. The main accessory pigment is peridinin. The SSU, ITS regions, and D1-D3 LSU rDNA sequences differ by 1.2-7.4%, >8.8%, and >2.5%, respectively, from those of the other known genera in the order Suessiales. Moreover, the SSU rDNA sequence differed by 1-2% from that of the three most closely related species, Polarella glacialis, Pelagodinium bei, and Protodinium simplex. In addition, the ITS1-5.8S-ITS2 rDNA sequence differed by 16-19% from that of the three most closely related species, Gymnodinium corii, Pr. simplex, and Pel. bei, and the LSU rDNA sequence differed by 3-4% from that of the three most closely related species, Protodinium sp. CCMP419, B. adriatica, and Gymnodinium sp. CCMP425. A. granifera had a 51-base pair fragment in domain D2 of the large subunit of ribosomal DNA, which is absent in the genus Biecheleria. In the phylogenetic tree based on the SSU and LSU sequences, A. granifera is located in the large clade of the family Suessiaceae, but it forms an independent clade.

• Research in Plant Disease
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• v.11 no.1
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• pp.56-65
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• 2005

To establish taxonomic system of morphologically similar species of small-spored Alternaria, phylogenetic analysis of internal transcribed spacer (ITS 1, ITS 2 and 5.8S rDNA) and mitochondrial small subunit (mt SSU) rDNA sequences and URP-PCR fingerprinting analysis from 11 species ofAlternaria were performed. Phylogenetic analysis of ITS and mt SSU rDNA sequences revealed that 10 out of 11 species of the smallspored Alternaria were phylogenetically identical with a bootstrap value of 100%. A. infectoria only was phylogenetically differentiated from the other species. The results suggest that the 10 small-spored Alternaria species are very closely related evolutionally and the markers can not be used for differentiation of the smallspored Alternaria species. URP-PCR fingerprinting analysis from eleven species of smallspored Alternaria using 10 URP primers showed that it was possible to differentiate the species, although genetic similarities were found among the species. The Alternaria sp. from common pokeweed could be distinguished from other species by URP-PCR analysis, and it was considered as a new species. A. infectoria could be easily distinguished from the other 10 species by phylogenetic analysis of ITS and mt SSU rDNA sequences and the URPPCR fingerprinting analysis.

• ALGAE
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• v.21 no.2
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• pp.209-216
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• 2006

The characteristics of Peyssonnelia capensis Montagne (Peyssonneliaceae, Rhodophyta) from Jeju Island were investigated in order to clarify the species entity and re-evaluate taxonomic position. The morphological variations of the Peyssonnelia capensis from Jeju Island were divided into two types, the thin thallus type and the thick thallus type. The thin thallus type is characterized by thin, soft, orbicular, slightly lobed thallus with entire to undulate margin, and compact rhizoids. The thick thallus type has thick and stiff thallus with sinuate margin and scattered rhizoids, and has more branches than the thin thallus type. The basal layer and the epithallium of thin thallus type are similar to those of thick thallus types in their structure. However, the hypothallial cells of the thick thallus type are longer than those of the thin thallus type. The erect filament of thick thallus type has more cells than those of the thin thallus type. Tetrasporangial nemathecia are distinctly protruded. Mature tetrasporangia of this species are divided cruciately into four spores as those of other Peyssonneliaceae. In addition to their morphological and anatomical distinctness between two types, the nucleotide sequence analyses of SSU and ITS2 region make no differences among populations from Jeju and other localities in Korea. Therefore these two morphological variation may not base on genetic variation.

• Mycobiology
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• v.42 no.2
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• pp.174-180
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• 2014

We analyzed the genetic diversity of Cylindrocarpon destructans isolates obtained from Korean ginseng (i.e., Panax ginseng) roots by performing virulence tests and nuclear ribosomal gene internal transcribed spacer (ITS) and mitochondrial small subunit (mt SSU) rDNA sequence analysis. The phylogenetic relationship analysis performed using ITS DNA sequences and isolates from other hosts helped confirm that all the Korean C. destructans isolates belonged to Nectria/Neonectria radicicola complex. The results of in vivo and ex vivo virulence tests showed that the C. destructans isolates could be divided into two groups according to their distinctive difference in virulence and the genetic diversity. The highly virulent Korean isolates in pathogenicity group II (PG II), together with foreign isolates from P. ginseng and P. quinquefolius, formed a single group. The weakly virulent isolates in pathogenicity group I, together with the foreign isolates from other host plants, formed another group and exhibited a greater genetic diversity than the isolates of PG II, as confirmed by the mt SSU rDNA sequence analysis. In addition, as the weakly virulent Korean isolates were genetically very similar to the foreign isolates from other hosts, they were likely to originate from hosts other than the ginseng plants.

• ALGAE
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• v.33 no.1
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• pp.1-19
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• 2018

Members of the family Parviluciferaceae (Alveolata, Perkinsozoa) are the well-known dinoflagellate parasitoids along with Amoebophrya ceratii species complex and parasitic chytrid Dinomyces arenysensis and contain six species across three genera (i.e., Parvilucifera infectans, P. sinerae, P. rostrata, and P. corolla, Dinovorax pyriformis, and Snorkelia prorocentri) so far. Among Parvilucifera species, the two species, P. infectans and P. sinerae, are very similar or almost identical each other morphologically and genetically, thereby make it difficult to distinguish between the two. The only main difference between the two species known so far is the number of sporangium wall (i.e., 2 layers in P. infectans vs. 3 layers in P. sinerae). During sampling in Masan bay, Korea during the spring season of 2015, the dinoflagellate Akashiwo sanguinea cells infected by the parasite Parvilucifera were observed and this host-parasite system was established in culture. Using this culture, its morphological and ultrastructural features with special emphasis on the variation in the number of sporangium wall over developmental times, were investigated. In addition, the sequences of rDNA regions and ${\beta}-tubulin$ genes were determined. The result clearly demonstrated that the trophocyte at 36 h was covered with 4 layers, and then outer layer of the sporocyte gradually degraded over time, resulting in wall structure consisting of two layers, with even processes being detached from 7-day-old sporangium with smooth surface, indicating that the difference in the number of layers seems not to be an appropriate ultrastructural character for distinguishing P. infectans and P. sinerae. While pairwise comparison of the large subunit rDNA sequences showed 100% identity among P. infectans / P. sinerae species complex, genetic differences were found in the small subunit (SSU) rDNA sequences but the differences were relatively small (11-13 nucleotides) compared with those (190-272 nucleotides) found among the rest of Parvilucifera species (P. rostrata and P. corolla). Those small differences in SSU rDNA sequences of P. infectans / P. sinerae species complex may reflect the variations within inter- strains of the same species from different geographical areas. Taken together, all morphological, ultrastructural, and molecular data from the present study suggest that they are the same species.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.281-289
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• 2019

Since 2013, more than 100 Entoloma (Entolomataceae, Agaricales) collections have been made during field investigations of mushroom flora in Korea. Among these collections, three Entoloma species were identified as new records from Korea. Morphological examinations were made based on the macro- and micro-morphological features of the isolates collected during field visits. To ensure the identity of the isolates at the species level, DNA sequences from four gene regions (rpb2, ITS, 28S, and mtSSU) were compared. To the best of our knowledge, these are the first records of E. aprile, E. chytrophilum, and E. hirtipes in Korea. Comprehensive descriptions, photographs, and phylogenetic examinations are presented here.

• The Korean Journal of Mycology
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• v.50 no.3
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• pp.195-204
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• 2022

A fungal strain, designated KNUF-20-NI009, was isolated from soil collected from Gunsan-si, Jeollabuk-do, Korea. The isolate showed cultural features typical of the genus Xenoroussoella. Colonies cultivated on malt extract agar were olivaceous-brown to pale olivaceous-white at the margins, with undersides of dark olivaceous to olivaceous-brown and a white margin. The conidia, with a size range of 2.7-5.1×1.6-3.3 ㎛ ($\bar{x}=3.6\times2.6{\mu}m$, n=50), were globoid to ellipsoid in shape, hyaline when immature, becoming light brown to golden-brown when mature, and characterized by 1 or 2 guttules. Multi-locus sequence analysis based on a combined dataset of internal transcribed spacer regions (ITS), large subunit rDNA (LSU), small subunit rDNA (SSU), translation elongation factor 1-alpha (TEF1α), and RNA polymerase II largest subunit (RPB2) sequences revealed KNUF-20-NI009 to be a strain of Xenoroussoella triseptata. This is the first report of this species in Korea.