• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.290-297
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• 2015

Based on the place of its origin, pear tree (Pyrus spp.) is largely divided into European pears (P. communis, cultivated mainly in Europe and the U.S.) and Asian pears (P. pyrifolia, P. bretschneideri, and P. ussuriensis, distributed and grown in East Asian countries including China, Japan, and Korea). Most pear trees have 17 chromosomes (diploidy, 2n=2x=34). Their genetic studies and precise cultivar breeding are highly restricted by conditions such as self-incompatibility controlled by S-locus and juvenility as one major character of fruit crops. Genetic studies on Pyrus have been promoted by the development of various molecular markers. These markers are being utilized actively in various genetic studies, including genetic relationship analysis, genetic mapping, and QTL analysis. In addition, research on pear genetic linkage maps has been extended to studies for the identification of QTL for target traits such as disease resistance and genetic loci of useful traits. NGS technology has radically reduced sequencing expenses based on massive parallel reactions to enable high-capacity and high-efficiency. NGS based genome analyses have been completed for Chinese pear 'Danshansuli' and European pear 'Bartlett'. In Korea, GWAS for agricultural valuable traits such as floral structure, ripening, and total soluble contents have been conducted through resequencing. GBS has been performed for 'Whangkeumbae', 'Cheongsilri', and 'Minibae'.

• Journal of Plant Biotechnology
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• v.45 no.1
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• pp.17-29
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• 2018

This study was conducted to investigate a morphological trait in 294 rice accessions including Korean breeding lines. We also carried out a genome-wide association study (GWAS) to detect significant single nucleotide polymorphism markers and candidate genes affecting major agronomic traits. A Manhattan plot analysis of GWAS using morphological traits showed that phenotypic and statistical significance was associated with a chromosome in each group. The significance of SNPs that were detected in this study was investigated by comparing them with those found previously studied QTL regions related to agronomic traits. As a result, SNP (S8-19815442), which is significant with regard to leaf angle, was located in the known QTL regions. To observe gene mutations related to leaf angle in a candidate gene, Os08g31950, its sequences were compared with sequences in previously selected rice varieties. In Os08g31950, a single nucleotide mutation occurred in one region. To compare relative RNA expression levels of candidate gene Os08g31950, obtained from GWAS analysis of 294 rice accessions and related to lateral leaf angle, we investigated relative levels by selecting 10 erect leaf angle varieties and 10 horizontal leaf angle varieties and examining real-time PCR. In Os08g31950, a high level of expression and various expression patterns were observed in all tissues. Also, Os08g31950 showed higher expression levels in the erect leaf angle variety group and higher expression rates in the leaf than in the root. The candidate gene detected through GWAS would be useful in developing new rice varieties with improved yield potential through future molecular breeding.

• Genomics & Informatics
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• v.1 no.2
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• pp.108-112
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• 2003

We have constructed a molecular linkage map of pepper (Capsicum spp.) in an interspecific $F_2$ population of 107 plants with 320 RFLP, 136 AFLP, and 46 SSR markers. The resulting linkage map consists of 15 linkage groups covering 1,720 cM with an average map distance of 3.7 cM between framework markers. Most RFLP markers ($80\%$) were pepper-derived clones and these markers were evenly distributed all over the genome. Genes for defense and biosynthesis of carotenoids and capsaicinoids were mapped on this linkage map. By using 30 primer combinations, AFLP markers were generated in the $F_2$ population. For development of SSR markers in Capsicum, microsatellites were isolated from two small-insert genomic libraries and the GenBank database. This combined map provides a starting point for high-resolution QTL analysis, gene isolation, and molecular breeding.

• Korean Journal of Agricultural Science
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• v.45 no.1
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• pp.1-8
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• 2018

Glucosinolates are one of the important plant secondary metabolites that are produced mainly in Brassicaceae plants. The compounds are primarily involved in defense responses to biotic and abiotic resistance in plants and play important biological roles during plant growth and development. In this study, the glucosinolate profiles in leaves of two different Brassica oleracea populations were compared using high-performance liquid chromatography (HPLC). The nine major glucosinolates compounds in cabbage leaves were identified as belonging to the aliphatic and indolic groups. Among them, sinigrin, which belongs to the aliphatic group, was recorded to be 41% whereas glucobrassicin and 4-methoxyglucobrassicin, which belong to the indolic group, were recorded to be 53.8%. In addition, we performed a genetic analysis to identify regions of the genome regulating glucosinolates biosynthesis in the $F_3$ population of Brassica oleracea. A total of 9 glucosinolates were used for the quantitative trait locus (QTL) analysis. Out of 9, a total of 3 QTLs were identified and they were associated with sinigrin, glucobrassicin, and 4-methoxyglucobrassicin synthesis located in Chromosome 1 and Chromosome 8, respectively. The results of this study will provide valuable information for the breeding of cabbage containing high glucosinolate content, and our next target is to develop component-specific and tightly linked markers for various glucosinolates.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.38-38
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• 2015

Throughout the world, clubroot disease is one of the most damaging diseases affecting Brassica oleracea. In order to perform QTL analysis of CR (clubroot resistance) loci in B. oleracea, we constructed a map, and analyzed CR-QTLs using the mean phenotypes of F3 progenies from the cross of a resistant double-haploid cabbage line (Anju) with a susceptible double-haploid broccoli line (GC). We identified one major QTL, pb-Bo(Anju)1 in C2 from Anju and four minor QTLs; pb-Bo(GC)1 in O5 from GC, pb-Bo(Anju)2, -3, -4 in C2, C3, and C7 from Anju, respectively. Additionally, we found that the accumulation of Pb-Bo(Anju)1 allele and the minor CR-QTLs is essential for resistance against various six isolates. Our finding markers closely linked to the CR-QTLs will help marker-assisted selection for CR. At present, we are undergoing toward map-based cloning for Pb-Bo(Anju)1 gene. The preliminary experiment delimited Pb-Bo(Anju)1 locus, encompassing among 450kB.

• The Plant Pathology Journal
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• v.29 no.3
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• pp.223-233
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• 2013

Rice stripe virus (RSV) is one of the most destructive viruses of rice, and greatly reduces rice production in China, Japan, and Korea, where mostly japonica cultivars of rice are grown. RSV is transmitted by the small brown plant-hopper (SBPH) in a persistent and circulative-propagative manner. Several methods have been developed for detection of RSV, which is composed of four single-stranded RNAs that encode seven proteins. Genome sequence data and comparative phylogenetic analysis have been used to identify the origin and diversity of RSV isolates. Several rice varieties resistant to RSV have been selected and QTL analysis and fine mapping have been intensively performed to map RSV resistance loci or genes. RSV genes have been used to generate several genetically modified transgenic rice plants with RSV resistance. Recently, genome-wide transcriptome analyses and deep sequencing have been used to identify mRNAs and small RNAs involved in RSV infection; several rice host factors that interact with RSV proteins have also been identified. In this article, we review the current statues of RSV research and propose integrated approaches for the study of interactions among RSV, rice, and the SBPH.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.259-259
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• 2022

Soil salinity is a major factor that reduces crop yields. The amount of soil affected by salinity is about 83 million hectares (FAO 2000), which is increasing due to the effects of climate change. In soybean [Glycine max (L.) Merr.], nutritional properties such as protein, starch, and sucrose content together with biomass and yield tends to reduce due to excessive salt. As a result of QTL mapping using the 169 F_2:3 population from the KA-1285 (salt-tolerant) × Daepung (salt-sensitive) in a previous study, two major QTLs (Gm03_39796778 and Gm03_40600088) related to salt tolerance were found on chromosome 3. In this study, the CDS region of the Gmsalt3 gene was analyzed using the ABI 3730x1 DNA Analyzer (Macrogen, Korea). The sequence of Gmsalt3 gene in KA-1285 was compared with Williams 82.a4.vl and PI483463 (Glycine soja). Two transversions were found at exon6 in KA-1285 and PI483463. Currently, whole genome sequencing and variation analysis using the Illumine Novaseq 6000 machine (Illumina, USA) are in progress. The results of this study can provide useful molecular markers for the selection of salt-tolerant soybeans and can be used as basic data for future salt-tolerant gene research.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.10a
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• pp.319-319
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• 2017

• Horticultural Science & Technology
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• v.31 no.4
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• pp.473-482
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• 2013

Molecular markers, as an efficient selection tool, have been and is being used for practical breeding program in chili pepper (Capsicum annuum L.). Recently, a lot of researches on inheritance and genetic analysis for quantitative traits including capsaicinoids, carotenoids, and sugar content in pepper are being performed worldwide. It has been also reported that QTL mapping is a necessary tool to develop molecular markers associated with the quantitative traits. In this study, we suggested a new method to construct a pepper genetic map using SNP (HRM) markers generated from NGS resequencing of female and male parents. Plant materials were C. annuum 'NB1' (female parent), C. chinense 'Jolokia' (male parent), and their $F_2$ population consisting of 94 progenies. Sequences of 4.6 Gbp and 6.2 Gbp were obtained from NGS resequencing of 'NB1' and 'Jolokia', respectively. Totally, 4.29 million SNPs between 'NB1' and 'Jolokia' were detected and the 1.76 million SNPs were clearly identified. Among them, total 145 SNP (HRM) primer pairs covering pepper genetic map were selected, and the 116 SNP (HRM) markers of them were located on this map. Total distance of the map, which consisted of 12 linkage groups and matched with basic chromosome numbers of pepper, was 1,167.9 cM. According to the mapping result, we concluded that our mapping method was suitable to construct a pepper genetic map fast and accurately. In addition, the genetic map could be directly used for QTL analysis of traits different between both parents.

• Journal of Crop Science and Biotechnology
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• v.11 no.4
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• pp.269-276
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• 2008

Field resistance is defined as the resistance that allows effective control of a parasite under natural field condition and is durable when exposed to new races of that parasite. To identify the genes for field resistance to rice blast, quantitative trait loci (QTLs) conferring the resistance for races and blast nursery screening in japonica rice cultivars were detected and mapped using SSR markers. QTL analysis was carried out in 190 RILs population from the cross between Suweon365 (moderately resistant) and Chucheong (highly susceptible). Twelve QTLs against nine blast races inoculated were detected on chromosomes 1, 2, 4, 6, 7, 11 and 12. They explained from 5.1% to 34.9% of total phenotypic variation. Eight QTLs against blast nursery screening in four regions for three years were detected on chromosomes 1, 2, 4, 11 and 12. The phenotypic variation explained by each QTL ranged from 4.3% to 37.7%. Three chromosome segment substitution lines (CSSLs) of $BC_2F_6$ by backcross method were developed to transfer the QTLs into the susceptible cultivar Chucheong as a recurrent parent. A CSSL4-1 containing two QTLs qLB6.2 and qLB7 against blast races showed to the reaction of 6 to 7 at blast nursery in two regions for two years. The CSSL4-2 and CSSL93 containing QTLs, qLB11.2 and qLB12.1 of the resistance against leaf blast in blast nursery screening, respectively, had enhanced the resistance for blast nursery screening across two regions and in two years.