• Research in Plant Disease
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• v.13 no.1
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• pp.24-29
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• 2007

A total of 35 strains of Ralstonia solanacearum isolated from wilted pepper and tomato plants in Korea were analyzed for their genetic diversity by bacteriological, pathological and molecular biological approaches. All the strains were identified as R. solanacearum biovar 4 on the basis of physiological and biochemical tests, and species-specific PCR primers. Pathogenicity of the strains was confirmed by inoculating on 4-week-old pepper and tomato seedlings. Using cluster analysis based on repetitive sequence-based polymerase chain reaction (rep-PCR) genomic fingerprints, R. solanacearum strains isolated from pepper and tomato in Korea divided into 6 groups showing a high degree of genetic diversity at 55% similarity level. The genetic diversify of strains was not significantly correlated with their geographic origins and host plants.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.263-272
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• 2010

One hundred sixty three strains showing different colony morphological characteristics on different concentration of marine agar (MA) plates were isolated from ambient seawater near Dokdo island. Bacterial diversity and distributions were studied by phylogenetic analysis of the partial 16S rRNA gene sequences. One hundred sixty three strains were partially sequenced and analyzed phylogenetically. They were composed of 5 phyla, of which gamma-proteobacteria (58%), alpha-proteobacteria (20%), bacteriodetes (16%) were predominant. They were affiliated with 90 species. The 16S rRNA sequence similarity of the isolates was in 93.3 to 100 % range to reported sequence data. Thirty six isolates of among them were assumed to be novel species candidates based on similarity analysis of the 16S rRNA gene sequences. Overall, Proteobacteria and Bacteriodetes of the Dokdo coastal sea water showed a high diversity.

• The Plant Pathology Journal
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• v.37 no.5
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• pp.476-488
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• 2021

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot for cruciferous vegetables worldwide, especially for the cole crops such as cabbage and cauliflower. Due to the lack of resistant cabbage cultivars, black rot has brought about considerable yield losses in recent years in China. Understanding of the pathogen features is a key step for disease prevention, however, the pathogen diversity, population structure, and virulence are largely unknown. In this study, we studied 50 Xcc strains including 39 Xcc isolates collected from cabbage in 20 regions across China, using multilocus sequence genotyping (MLST), repetitive DNA sequence-based PCR (rep-PCR), and pathogenicity tests. For MLST analysis, a total of 12 allelic profiles (AP) were generated, among which the largest AP was AP1 containing 32 strains. Further cluster analysis of rep-PCR divided all strains into 14 DNA groups, with the largest group DNA I comprising of 34 strains, most of which also belonged to AP1. Inoculation tests showed that the representative Xcc strains collected from diverse regions performed differential virulence against three brassica hosts compared with races 1 and 4. Interestingly, these results indicated that AP1/DNA I was not only the main pathotype in China, but also a novel group that differed from the previously reported type races in both genotype and virulence. To our knowledge, this is the first extensive genetic diversity survey for Xcc strains in China, which provides evidence for cabbage resistance breeding and opens the gate for further cabbage-Xcc interaction studies.

• Korean Journal of Veterinary Service
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• v.42 no.3
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• pp.161-167
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• 2019

The poultry red mite (PRM), Dermanyssus gallinae, causes great economic losses to poultry industries in Korea. The molecular epidemiological characterization of PRM has been investigated in some countries, but those analysis has been not conducted yet in Korea. The aim of this study is to determine the genetic diversity of PRMs in Korea compared with those from other countries. Here, 13 PRM samples collected from Korea were analyzed with a part of the mitochondrial cytochrome oxidase subunit I (COI) gene and nuclear internal transcribed spacers (ITS) region. All the samples showed an identical COI sequence, which has also been reported in European countries and Japan. Phylogenetic diversity analysis showed that the mites from Korea were genetically related to those in other countries. The nuclear ITS region sequences were classified into three sequence types. Additionally, one of the ITS sequences was an intermediate type, implying that a hybridization event occurred among the mite populations in Korea. These findings suggested PRMs from Korea showed low genetic diversity with respect to mitochondrial COI gene, but three different populations inhabited in Korea with respect to nuclear ITS region sequences.

• Journal of Mushroom
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• v.18 no.4
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• pp.323-330
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• 2020

Agaricus bisporus is an important edible mushroom that is used as a functional food. In this study, European A. bisporus strains were analyzed for genetic diversity, population structure, and genetic differentiation using simple sequence repeat (SSR) markers. European A. bisporus strains were divided into four groups by distance-based analysis and two subpopulations by model-based analysis. The SSR markers used in this study did not group European A. bisporus strains by geographical region or pileus color. Genetic diversity was high in Group 4 based on distance-based analysis and Pop. 2 based on model-based analysis. A. bisporus strains showed very low genetic differentiation. The results of this study can be used for breeding A. bisporus in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.154-158
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• 2003

In this paper, Error rate performance of BCH coded DS-CDMA 16 QAM signal is analyzed using selective combining Diversity reception techniques in the environments of Rician fading. First in the performance of DS-CDMA 16 QAM signal in Rician fading channel, Second using SC diversity recepting techniques, and third using both diversity and BCH coding error rate performance is evaluated. from the results of Numerical analyzed it is found that a synergistic performance improvement is shown due to both diversity reception and coding techniques overcoming mobile wireless data communication channel environments.

• Korean Journal of Medicinal Crop Science
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• v.21 no.3
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• pp.220-228
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• 2013

This study was conducted to assess the genetic diversity and population structure of 70 amaranth accessions collected from South and Southeast Asia using 14 simple sequence repeat (SSR) markers. In total, 67 alleles were detected, with an average of 4.79 per locus. Rare alleles comprised a large portion (46.3%) of the detected alleles, and 29 unique alleles associated with rice accessions were also discovered. The mean major allele frequency (MAF), genetic diversity (GD) and polymorphic information content (PIC) of the 14 SSR loci were 0.77, 0.36, and 0.34, respectively. A model-based structural analysis revealed the presence of three subpopulations. The genetic relationships revealed by the neighbor-joining tree method were fairly consistent with the structure-based membership assignments for most of the accessions. All 70 accessions showed a clear relationship to each cluster without any admixtures. We observed a relatively low extent of genetic exchange within or among amaranth species from South and Southeast Asia. The genetic diversity results could be used to identify amaranth germplasms and so facilitate their use for crop improvement.

• The Korean Journal of Mycology
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• v.46 no.4
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• pp.375-382
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• 2018

Members of the genus Mortierella (Mortierellales) are filamentous fungi, which are found on nearly all substrates, but more frequently in soil. Till date, 7 species of Mortierella have been reported in Korea, but being a ubiquitous group with high species diversity in temperate zones, this number is still low. During a survey of fungal biodiversity in Korea, we collected many isolates of Mortierella, and through morphological and molecular phylogenetic analyses, identified them to be 3 previously unrecorded species, namely, M. chienii, M. epicladia, and M. gamsii. A total of 10 Mortierella species in Korea, including the 3 species reported in the present study, are widely distributed in 5 out of 7 phylogenetic groups of this genus. This indicates that the diversity of Mortierella was so far underestimated in Korea. Multi-locus sequence analysis is required to provide a more reliable backbone for some uncertain phylogenetic groupings and to more clearly define a species of Mortierella, which would encourage deeper research in the diversity and ecological roles of Mortierella and allied genera.

• Mycobiology
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• v.47 no.1
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• pp.76-86
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• 2019

Scab disease caused by Venturia nashicola is of agroeconomic importance in cultivation of Asian pear. However, little is known about the degree of genetic diversity in the populations of this pathogen. In this study, we collected 55 isolates from pear scab lesions in 13 major cultivation areas in Korea and examined the diversity using sequences of internal transcribed spacer (ITS) region, ${\beta}$-tubulin (TUB2), and translation elongation factor-$1{\alpha}$ ($TEF-1{\alpha}$) genes as molecular markers. Despite a low level of overall sequence variation, we found three distinctive subgroups from phylogenetic analysis of combined ITS, TUB2, and $TEF-1{\alpha}$ sequences. Among the three subgroups, subgroup 1 (60% of isolates collected) was predominant compared to subgroup 2 (23.6%) or subgroup 3 (16.4%) and was distributed throughout Korea. To understand the genetic diversity among the subgroups, RAPD analysis was performed. The isolates yielded highly diverse amplicon patterns and none of the defined subgroups within the dendrogram were supported by bootstrap values greater than 30%. Moreover, there is no significant correlation between the geographical distribution and the subgroups defined by molecular phylogeny. Our data suggest a low level of genetic diversification among the populations of V. nashicola in Korea.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.1
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• pp.32-41
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• 2021

South Korea presently harbors less than 800 long-tailed gorals (Naemorhedus caudatus), an endangered species. I report for the first time on the taxonomic status and genetic diversity of the Korean species using non-invasive fecal sampling based on mitochondrial cytochrome b gene sequence analyses. To determine the taxonomic status of this species, I reconstructed a consensus neighbor-joining tree and generated a minimum spanning network combining haplotype sequences obtained from feces with a new goral-specific primer set developed using known sequences of the Korean goral and related species (e.g., Russian goral, Chinese goral, Himalayan goral, Japanese serow, etc.). I also examined the genetic diversity of this species. The Korean goral showed only three different haplotypes. The phylogenetic tree and parsimony haplotype network revealed a single cluster of Korean and Russian gorals, separate from related species. Generally, the Korean goral has a relatively low genetic diversity compared with that of other ungulate species (e.g., moose and red deer). I preliminarily showcased the application of non-invasive fecal sampling to the study of genetic characteristics, including the taxonomic status and genetic diversity of gorals, based on mitochondrial DNA. More phylogenetic studies are necessary to ensure the conservation of goral populations throughout South Korea.