• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 추계학술대회 및 정기총회
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• pp.41-41
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• 2015

Oomycetes belong to the kingdom Straminipila, a remarkably diverse group which includes brown algae and planktonic diatoms, although they have previously been classified under the kingdom Fungi. These organisms have evolved both saprophytic and pathogenic lifestyles, and more than 60% of the known species are pathogens on plants, the majority of which are classified into the order Peronosporales (includes downy mildews, Phytophthora, and Pythium). Recent phylogenetic investigations based on DNA sequences have revealed that the diversity of oomycetes has been largely underestimated. Although morphology is the most valuable criterion for their identification and diversity, morphological species identification is time-consuming and in some groups very difficult, especially for non-taxonomists. DNA barcoding is a fast and reliable tool for identification of species, enabling us to unravel the diversity and distribution of oomycetes. Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The mitochondrial cox2 gene has been widely used for identification, taxonomy and phylogeny of various oomycete groups. However, recently the cox1 gene was proposed as a DNA barcode marker instead, together with ITS rDNA. To determine which out of cox1 or cox2 is best suited as universal oomycete barcode, we compared these two genes in terms of (1) PCR efficiency for 31 representative genera, as well as for historic herbarium specimens, and (2) in terms of sequence polymorphism, intra- and interspecific divergence. The primer sets for cox2 successfully amplified all oomycete genera tested, while cox1 failed to amplify three genera. In addition, cox2 exhibited higher PCR efficiency for historic herbarium specimens, providing easier access to barcoding type material. In addition, cox2 yielded higher species identification success, with higher interspecific and lower intraspecific divergences than cox1. Therefore, cox2 is suggested as a partner DNA barcode along with ITS rDNA instead of cox1. Including the two barcoding markers, ITS rDNA and cox2 mtDNA, the multi-locus phylogenetic analyses were performed to resolve two complex clades, Bremia lactucae (lettuce downy mildew) and Peronospora effuse (spinach downy mildew) at the species level and to infer evolutionary relationships within them. The approaches discriminated all currently accepted species and revealed several previously unrecognized lineages, which are specific to a host genus or species. The sequence polymorphisms were useful to develop a real-time quantitative PCR (qPCR) assay for detection of airborne inoculum of B. lactucae and P. effusa. Specificity tests revealed that the qPCR assay is specific for detection of each species. This assay is sensitive, enabling detection of very low levels of inoculum that may be present in the field. Early detection of the pathogen, coupled with knowledge of other factors that favor downy mildew outbreaks, may enable disease forecasting for judicious timing of fungicide applications.

• 대한의생명과학회지
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• 제16권3호
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• pp.187-192
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• 2010

The aim of this study was to compare the results of morphological phenotypic examination and molecular biological method, randomly amplified polymorphic DNA (RAPD) using clinical isolates from Korean patients infected with dermatophytes. A total of 44 clinical isolates have been collected by Korean Collection Medical Fungi (KCMF) and those were subjected for the RAPD analysis. The results showed that the fungal strains that have RG1 band patterns were identified as Trichophyton rubrum by the neighbour-joining analysis. Additionally, other fungal strains that have RG3 band patterns were identified as Epidermophyton floccosum and RG5 band patterns were identified as Micorsporum gypseum. Even though molecular biological method such as RAPD are not necessary, it might be useful when some strains have similar morphological characteristics or when same species has phenotypic variations. In this study, therefore, we targeted internal transcribed spacer (ITS) regions of fungal rDNA, performed RAPD and then compared with morphological phenotypic examination.

• 한국자원식물학회지
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• 제24권4호
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• pp.358-369
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• 2011

괭이눈속 식물에 대한 계통 유연관계를 알아보기 위하여 핵 rDNA의 internal transcribed spacer(ITS) 지역에 대한 염기서열을 분석하였다. 5.8s를 포함한 ITS 염기서열은 647-653 bp로 그중 219개의 염기에서 유전적 다양성을 나타내었다. 정렬된 염기서열은 bootstrap을 포함한 parsimony 방법과 neighbor-joining 방법을 통하여 계통수를 평가하였다. 그 결과 C. pseudofauriei(선괭이눈)이 군내군의 가장 기부에 분계조를 형성하였고, Ser. Pilosa and Ser. Oppositifolia와 Ser. Alternifolia and Ser. Flagellifera가 높은 bootstrap 값으로 두 개의 분계조를 각각 형성하였다. Neighbor-joining 분석의 결과도 일치하였다. 본 연구결과 핵 rDNA의 ITS 염기서열 분석은 괭이눈속의 계통학적 연구에 유용한 마커로 확인되었으며, 최종적으로 ITS 염기서열과 종자 형태형질을 바탕으로 C. sphaerospermum Maxim. and C. valdepilosum (Ohwi) S.H. Kang & J.W. Han에 대한 분류학적 검토를 하였다.

• Fisheries and Aquatic Sciences
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• 제13권4호
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• pp.272-277
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• 2010

Seagrasses are marine angiosperms of ecological importance in providing shelter and food to aquatic species as well as maintaining the carbon cycle on earth. Phyllospadix iwatensis is a seagrass of the family Zosteraceae and is distributed along the eastern coast of Korea. The nucleotide sequences of P. iwatensis nuclear genes encoding 18S ribosomal RNA (rRNA) and internal transcribed spacer-1 (ITS-1) were determined for molecular phylogenetic analysis. Genomic DNA was isolated from P. iwatensis and used for PCR amplification of 18S rRNA and ITS-1. Examination of the 18S rRNA sequence of P. iwatensis showed a close (99% similarity) relationship to Zostera noltii, another genus of Zosteraceae, but a distant (84% similarity) evolutionary relationship to other macroalgal Laminariales species. Further discrepancies found in ITS-1 nucleotide sequences between closely related species indicate that the sequence information could be used for species identification.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1997년도 한국생물과학협회 학술발표대회
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• pp.94.2-94
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• 1997

• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
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• pp.50.2-50
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• 1999

• 한국육종학회지
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• 제43권4호
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• pp.252-259
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• 2011

Conventional staining and fluorescence in situ hybridization (FISH) karyotypes of the non-genetically modified (GM) parental rice line, 'Nakdong' (Oryza sativa L. japonica), and its four GM rice lines, LS28 (event LS30-32-20-1), Cry1Ac1 (event C7-1-9-1), and LS28 ${\times}$ Cry1Ac1 (events L/C1-1-3-1 and L/C1-3-1-1) were analyzed using 5S and 45S rDNAs as probes. Both parental and transgenic lines were diploids (2n=24) with one satellite chromosome pair. The lengths of the prometaphase chromosomes ranged from 1.50 to $6.30{\mu}m$. Four submetacentric and eight metacentric pairs comprised the karyotype of 'Nakdong' and its four GM lines. One pair of 5S rDNA signals was detected near the centromeric region of chromosome g in both the parental and transgenic lines. The 45S rDNA signals were detected on the secondary constrictions of the satellite chromosome pair in both the parental and transgenic lines. There was no significant difference in chromosome size, length, and composition between 'Nakdong' and its four GM lines. This research was conducted as a preliminary study for chromosomal detection of transgenes in GM rice lines and would be useful for their breeding programs.

• 한국자원식물학회지
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• 제30권6호
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• pp.654-661
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• 2017

Dual-color fluorescence in situ hybridization karyotype analysis was created using repetitive sequences including two types of rDNA repeats (45S and 5S rDNAs) and Arabidopsis-type telomere sequence repeats. The somatic metaphase cells of Carthamus tinctorius were observed as diploids (2n=2x=24). A symmetrical or slightly asymmetrical karyotype with seven pairs of metacentric and five pairs of submetacentric chromosomes was observed. The lengths of the somatic metaphase chromosomes ranged from 4.18 to $6.53{\mu}m$, with a total length of $60.71{\mu}m$. One locus of 45S rDNA was located on the pericentromeric regions of three pairs of chromosomes and the other pair was situated on the terminal regions of the short arms of a single pair of chromosomes. One locus of 5S rDNA was detected on the interstitial regions of the short arms of two pairs of chromosomes. Arabidopsis-type telomeric repeats were detected on the terminal regions of all pairs of chromosomes. Co-localization of loci between telomeric repeats and 45S rDNA was observed in a single pair of chromosomes. The results provide additional information for the existing physical mapping project of C. tinctorius and will also serve as a benchmark to a more intricate cytogenetic investigation of C. tinctorius and its related species.

• The Plant Pathology Journal
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• 제15권5호
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• pp.287-294
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• 1999

A technique based on the polymerase chain reaction (PCR) for the specific detection of genus Phytophthora and Phytophthora cryptogea-P. drechsleri complex group was developed using nucleotide sequence information of ribosomal DNA (rDNA) regions. The internal transcribed spacers (ITS) including 5.8S were sequenced for P. cryptogea-P. drechsleri complex group and its related species. Two pairs of oligonucleotide primers were designed. Primer pair ITS1/Phy amplified ca. 240 bp fragment in 12 out of 13 specie of Phytophthora, but not in Pythium spp., Fusarium spp.and Rhizoctonia solani. Primer pair rPhy/Pcd amplified 549 bp fragment only in P. cryptogea-P. drechsleri complex group, but not in other Phytophthora spp.and other genera. Specific PCR amplification using the primers was successful in detecting Phytophthora and P. cryptogea-P. drechsleri complex group in diseased plants.

• ALGAE
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• 제28권4호
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• pp.307-330
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• 2013

The genus Cryptomonas is easily recognized by having two flagella, green brownish color, and a swaying behavior. They have relatively simple morphology, and limited diagnostic characters, which present a major difficulty in differentiating between species of the genus. To understand species delineation and phylogenetic relationships among Cryptomonas species, the nuclear-encoded internal transcribed spacer 2 (ITS2), partial large subunit (LSU) and small subunit ribosomal DNA (rDNA), and chloroplast-encoded psbA and LSU rDNA sequences were determined and used for phylogenetic analyses, using Bayesian and maximum likelihood methods. In addition, nuclear-encoded ITS2 sequences were predicted to secondary structures, and were used to determine nine species and four unidentified species from 47 strains. Sequences of helix I, II, and IIIb in ITS2 secondary structure were very useful for the identification of Cryptomonas species. However, the helix IV was the most variable region across species in alignment. The phylogenetic tree showed that fourteen species were monophyletic. However, some strains of C. obovata had chloroplasts with pyrenoid while others were without pyrenoid, which used as a key character in few species. Therefore, classification systems depending solely on morphological characters are inadequate, and require the use of molecular data.