• Korean Journal of Plant Tissue Culture
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• v.22 no.4
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• pp.229-234
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• 1995

Anthers of hybrids and inbred lines of Chinese cabbage (Brassica campestris ssp. pekinensis) were inoculated on the modified solid or liquid B$_{5}$ medium after several pre-treatments. Anthers were then maintained at 25 $^{\circ}C$ after being subjected to various post-treatment. Somatic embryos began to appear 9 days after inoculation and ended at 13th days. Low temperature pre-treatment did not increase embryoid production whereas high post-treatment temperature of 4$0^{\circ}C$ or 45$^{\circ}C$ enhance the production. There were considerable levels differences in embryogenesis between lines used, but not between the culture methods. Somatic embryo yield was also increased by subjecting anthers to one day at 35$^{\circ}C$ and then another one day at 3$0^{\circ}C$ after plating. Histological observations showed several stages in haploid development ranging from a few celled to large multiple-celled embryoids.s.

• Journal of Plant Biotechnology
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• v.47 no.1
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• pp.26-39
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• 2020

In maize, immature embryos (IEs) are highly regenerative explants most suitable for producing high frequencies of plantlet regeneration in vitro. Apart from media, explants, and hormones, genotypic variation also influences in vitro characters to a great extent. In the present study, IEs were used to study the distinctive effect of variation of size/stage and hormones in different genotypes on five in vitro characters viz., frequency of callus induction, growth rate of total callus, frequency of E. callus induction, and volume and number of regenerated plantlets. LS medium with different concentrations of 2,4-D (0.5, 1.5, 2.5, 4.0 and 5.0 mg/L) were used to study the former four in vitro characters, and medium with 6-benzylaminopurine and kinetin (0.5 mg/L, each) was used for plantlet regeneration. IEs of 1.0, 1.5, 2.0, 2.5 and 3.0 mm in size were isolated from four inbred lines viz., NM74C, NM81A, NM5883 and NM5884. Two-way ANOVA revealed that explant size and genotypes, as well as hormonal concentrations showed significant effects on in vitro characters. Two millimeter IEs were found to be suitable for in vitro cultures. LS medium with 1.5 mg/L 2,4-D and LS with BAP and Kn (0.5 mg/L, each) were found to be the best hormonal concentrations for callus induction, maintenance, and regeneration, respectively. Among the four genotypes, NM81A and NM5883 yielded more non-embryogenic and Type I E. calli. In contrast, NM74C and NM5884 yielded more highly regenerative Type II calli. Inbred line NM5884 was found to be the best among these four genotypes.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.279-283
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• 2009

A new yellow waxy corn hybrid "Daehakchal Gold 1" was developed from single cross between Yeongdeok Jaera and Okchen Jaera at Chungnam National University in 2007. Inbred CNU57 derived from Yeongdeok Jaera was used as the seed parent of Daehakchal Gold 1, and inbred CNU 27 derived from Okchen Jaera as the pollen parent. Tasseling date of this hybrid was seven day later than that of check hybrid, Chalok 1. Daehakchal Gold 1 was 19.7cm in ear length and 4.5cm in ear diameter. The yield of Daehakchal Gold 1 and check hybrid in dry matter were 146.5g and 113.9g per plant, respectively. On yield trial, which were increased 29.7% compared with a check hybrid, Chalok 1. Especially, Daehakchal Gold 1 had yellow kernels and good eating quality. The ratio of kernel set length/ear length was similar to Chalok 1. It is moderately resistant to Bioporalis maydis and corn borer. The yields of Daehakchal Gold 1 in fresh ear weight and in number of fresh ear were 16% and 8%, respectively, higher than those of a check hybrid in regional yield trials for three years. Seed production of this hybrid has gone well due to good match during crossing between seed and pollen parents.

• The Journal of Natural Sciences
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• v.11 no.1
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• pp.95-98
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• 1999

Chinese cabbage (Brassica campestris), one of the major vegetable crops in Korea, undergoes self-incompatible pathway for reproduction. To maintain inbred lines of chinese cabbage, a method in that $CO_2$ gas is treated to the pistils to break the self-incompatibility and thereby self-pollens can successfully make germination and fertilization has been selectively used in speed company. In this study, the pistil genes induced by the $CO_2$ treatment was investigated by mRNA differential display (DD-PCR) method. The result shows PCR products amplified in a differential pattern from both $CO_2$ gas treated- and untreated-pistil mRNAs, suggesting that the pistil genes are probably regulated positively and also negatively by the $CO_2$ gas.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.315-328
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• 2021

Fusarium and Rhizoctonia genera are important pathogens of many field crops worldwide. They are constantly evolving and expanding their host range. Selecting resistant cultivars is an effective strategy to break their infection cycles. To this end, we screened a collection of Medicago truncatula accessions against Fusarium oxysporum, Fusarium solani, and Rhizoctonia solani strains isolated from different plant species. Despite the small collection, a biodiversity in the disease response of M. truncatula accessions ranging from resistant phenotypes to highly susceptible ones was observed. A17 showed relative resistance to all fungal strains with the lowest disease incidence and ratings while TN1.11 was among the susceptible accessions. As an initiation of the characterization of resistance mechanisms, the antioxidant enzymes' activities, at the early stages of infections, were compared between these contrasting accessions. Our results showed an increment of the antioxidant activities within A17 plants in leaves and roots. We also analyzed the responses of a population of recombinant inbred lines derived from the crossing of A17 and TN1.11 to the infection with the same fungal strains. The broad-sense heritability of measured traits ranged from 0.87 to 0.95, from 0.72 to 0.96, and from 0.14 to 0.85 under control, F. oxysporum, and R. solani conditions, respectively. This high estimated heritability underlines the importance of further molecular analysis of the observed resistance to identify selection markers that could be incorporated into a breeding program and thus improving soil-borne pathogens resistance in crops.

• Plant Breeding and Biotechnology
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• v.5 no.4
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• pp.371-389
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• 2017

Supplying sufficient rice to growing populations is a global challenge. Hybrid indica rice varieties exploiting heterosis have increased yields, but inter-subspecific crosses between indica and japonica varieties are hampered by sterility. Examination and genetic understanding of yield heterosis in indica/japonica crosses addressing yield barriers are basic requirements. In this study, QTLs for heterosis of yield traits were identified in indica-japonica recombinant inbred lines (RILs) using a total of 178 RILs originating from Dasanbyeo (indica) ${\times}$ TR22183 (japonica) (DT-RILs) and their backcrossed populations. Nine of sixty-six major quantitative trait loci (QTLs) identified in DT-RILs exhibited heterosis. Heterosis QTLs clustered with other traits on chromosomes 1, 4, and 8, and clusters were conserved between different RILs. The clusters contained several known yield enhancement genes/QTLs. Specific heterotic allele combinations contributed to four major heterosis QTLs, particularly for panicle and spikelet number traits. Heterosis for yield and yield-related traits was explained by the harmonized effects of overdominance, dominance, and epistatic interactions in inter-subspecific breeding populations.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.65.2-65
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• 2003

To protect the plant against several soil-borne pathogens, we are currently constructing disease-resistant transgenic root stock for the growth of cucurbitaceae vegetable plants, watermelon and gourd. We made a watermelon cDNA library from Cladosporium cucumerinum-Infected leaves for substractive hybriazation and differential screening. We isolated the several pathogen inducible cDNA clones, such as caffeoyl-CoA-methyltransferase, LAA induced protein, receptor-like kinase homolog, hydroxyproline-rich glycoprotein, catalase, calmodulin binding protein, mitochondrial ATPase beta subunit, methyl tRNA synthetase and WRKY transcription factors. We previously obtained CaMADS in pepper and galactinol synthase ( CsGolS) in cucumber that were confirmed to be related with disease-resistance. CaMADS and CsGolS2 were transformed into the inbred line 'GO701-2' gourd, the inbred line '6-2-2' watermelon and the Kong-dye watermelon by Agrobacterium tumerfaciens LBA4404. Plant growth regulators (zeatin, BAP and IAA) were used for shoot regeneration and root induction for optimal condition. Putative transgenic plants were selected in medium containing 100mg/L kanamycin and integration of the CaMADS and CsGO/S2 into the genomic DNA were demonstrated by the PCR analysis. We isolated major soil-borne pathogens, such as Monosporascus cannonballus, Didymella bryoniae, Cladosporium cuvumerinum from the cultivation area of watermelon or root stock, and successfully established artificial inoculation method for each pathogen. This work was supported by a grant from BioGreen 21 program, Rural Development Administration, Republic of Korea.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.289-289
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• 2022

Waterlogging tolerance of corn is one of the important factor for cultivate in paddy soil condition to increase cultivation area and self-sufficiency of corn in Korea. In order to develop elite waterlogging tolerance corn, the new corn lines bred by crossing wild corn, Teosinte, and cultivated corn inbred lines. Five accessions among the 2 species, Zea mays sub spp. mexicana and Zea mays spp. parviglumis, of 81 Teosinte were selected through the waterlogging treatment. The waterlogging treatments were implemented for 7 days at the seedling(V3) stage. The inbred lines were developed by crossing 5 teosinte accessions and cultivated corn lines and they were estimated waterlogging tolerance. It was screened and analyzed the metabolites extracted from roots of 19KT-32(KS141 × teosinte) that was treated waterlogging. We selected 8 of 180 metabolites like as γ-aminobutyric acid(GABA), putrescine, citrulline, Gly, and Ala that expression was remarkably changed over 2.5-times, 7 metabolites increased and 1 metabolite decreased in waterlogging, respectively. Glutamate decarboxylase(GAD) catalyzing GABA accumulation gene have 10 haplotypes, and exon1 was highly conserved, but identified to 135 SNPs after the first intron. Among the 135 SNPs, the number of transversion mutations (52) surpassed the number of transition mutations (38). Most of metabolites were related to abiotic stress in plant that it regulated to pH, osmotic pressure K⁺/Ca⁺⁺ and ATPase activity. We are analyzing the association using these results for increase breeding efficiency.

• Journal of Plant Biotechnology
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• v.3 no.1
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• pp.33-38
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• 2001

Protoplasts isolated from inbred lines of Brassica oleracea L. var capitata (cabbage) and Brassica campestris L. ssp. pekinensis (Chinese cabbage) were fused by PEG-mediated method, and somatic hybrid cells were differentiated into plants. for the identification of somatic hybrid plants, ploidy level, plant morphology, and cytological analysis were performed. All of the regenerated plants derived from fused protoplasts were shown to be 2X-4X, or higher ploidy level, presumably due to somatic hybridization or chromosome doubling. The morphology of leaves, petioles, and flowers showed an intermediate phenotype between Chinese cabbage and cabbage. Chromosome numbers in these somatic hybrids ranged mostly from 33 to 38. According to Genomic in situ hybridization (GISH) pattern, signals from both fusion parents of B.campestris or B.oleracea were detected in different colors when chromosomes of putative somatic hybrids were observed.

• Journal of Gastric Cancer
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• v.14 no.2
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• pp.67-86
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• 2014

Gastric cancer is one of the most common cancers in the world. Animal models have been used to elucidate the details of the molecular mechanisms of various cancers. However, most inbred strains of mice have resistance to gastric carcinogenesis. Helicobacter infection and carcinogen treatment have been used to establish mouse models that exhibit phenotypes similar to those of human gastric cancer. A large number of transgenic and knockout mouse models of gastric cancer have been developed using genetic engineering. A combination of carcinogens and gene manipulation has been applied to facilitate development of advanced gastric cancer; however, it is rare for mouse models of gastric cancer to show aggressive, metastatic phenotypes required for preclinical studies. Here, we review current mouse models of gastric carcinogenesis and provide our perspectives on future developments in this field.