• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.317-322
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• 2009

The chicken major histocompatibility complex (MHC) is known to be associated with disease resistance and susceptibility to several pathogens. The microsatellite marker LEI0258 is physically located between the BG and BF of MHC region and variations near this marker have been well documented. In this report, the LEI0258 marker was used to find specific alleles for the Korean native chicken. The MHC haplotype was analyzed by PCR screening and sequencing of LEI0258 region in four different breeds including black Korean native chicken, brown Korean native chicken, Cornish and Rhode island red. The serologically same MHC haplotypes showed the differences in repeat numbers, a few indels or single nucleotide polymorphisms by sequencing analysis. Even though we could not identify specific alleles for Korean native chickens, the genotypes analyzed in these breeds can give valuable information for the relationships with disease resistance and establishment of breeding strategies for the Korean native chicken.

• Molecules and Cells
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• v.25 no.2
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• pp.205-210
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• 2008

To develop molecular markers linked to the $L^4$ locus conferring resistance to tobamovirus pathotypes in pepper plants, we performed AFLP with 512 primer combinations for susceptible (S pool) and resistant (R pool) DNA bulks against pathotype 1.2 of pepper mild mottle virus. Each bulk was made by pooling the DNA of five homozygous individuals from a T10 population, which was a near-isogenic $BC_4F_2$ generation for the $L^4$ locus. A total of 19 primer pairs produced scorable bands in the R pool. Further screening with these primer pairs was done on DNA bulks from T102, a $BC_{10}F_2$ derived from T10 by back crossing. Three AFLP markers were finally selected and designated L4-a, L4-b and L4-c. L4-a and L4-c each underwent one recombination event, whereas no recombination for L4-b was seen in 20 individuals of each DNA bulk. Linkage analysis of these markers in 112 $F_2$ T102 individuals showed that they were each within 2.5 cM of the $L^4$ locus. L4-b was successfully converted into a simple 340-bp SCAR marker, designated L4SC340, which mapped 1.8 cM from the $L^4$ locus in T102 and 0.9 cM in another $BC_{10}F_2$ population, T101. We believe that this newly characterized marker will improve selection of tobamovirus resistance in pepper plants by reducing breeding cost and time.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.912-923
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• 2016

Watermelon production is often limited by powdery mildew in areas with a large daily temperature range. Development of resistant watermelon cultivars can protect against powdery mildew; however, little is known about the characteristics of its causal agents. Here, we identified the genus and race of a causal pathogen of powdery mildew in Ansung province of South Korea, and developed molecular markers for the generation of resistant watermelon cultivars. The causal pathogen was determined to be Podosphaera xanthii based on multiple sequence alignments of internal transcribed spacers (ITS) of rDNA. The physiological race was identified as 1W, and the Ansung isolate was named P. xanthii 1W-AN. Following inoculation with the identified P. xanthii 1W-AN, we found inheritance of the resistant gene fitting a single dominant Mendelian model in a segregated population ('SBA' ${\times}$ PI 254744). To develop molecular markers linked to fungus-resistant loci, random amplified polymorphic DNA (RAPD) was accomplished between DNA pooled from eight near-isogenic lines (NILs; $BC_4F_6$), originated from PI 254744 and susceptible 'SBB' watermelon. After sequencing bands from RAPD were identified in all eight NILs and PI254744, 42 sequence-characterized amplifiedregion (SCAR) markers were developed. Overall, 107 $F_2$ plants derived from $BC_4F_6$ NIL-1 ${\times}$ 'SBB' were tested, and one SCAR marker was selected. Sequence comparison between the SCAR marker and the reference watermelon genome identified three Nco I restriction enzyme sites harboring a single nucleotide polymorphism, and codominant cleavage-amplified polymorphic site markers were subsequently developed. A CAPS marker was converted to a high-resolution melt (HRM) marker, which can discriminate C/T SNP (254PMR-HRM3). The 254PMR-HRM3 marker was evaluated in 138 $F_{2:3}$ plants of a segregating population ('SBA' ${\times}$ PI254744) and was presumed to be 4.3 cM from the resistance locus. These results could ensure P. xanthii 1W-AN resistance in watermelon germplasm and aid watermelon cultivar development in marker-assist breeding programs.

• Journal of Plant Biotechnology
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• v.37 no.2
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• pp.212-219
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• 2010

Selectable marker gene systems are vital for the development of transgenic plants, but the presence of selectable marker genes encoding antibiotic or herbicide resistance in genetically modified plants poses a number of problems. A lot of research results and various techniques have been developed to produce marker-free GM plants. The aim of this review is to describe the principal methods used for eliminating selectable marker genes to generate marker-free GM plants, concentrating on the three significant methods(co-transformation, site-specific recombinase-mediated excision, non-selected transformation) in several marker-free techniques.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.408-413
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• 2008

Rice blast resistance is considered one of the most important traits in rice breeding and the disease, caused by Magnaporthe grisea Barr, has brought significant crop losses annually. Moreover, breakdown of resistance normally occurs in two to five years after cultivar release, thus a more durable resistance is needed for better control of this disease. We developed a new variety, Keumo3, which showed strong resistance to leaf blast. It was tested in 2003 to 2007 at fourteen blast nursery sites covering entire rice-growing regions of South Korea. It showed resistance reactions in 12 regions and moderate in 2 regions without showing susceptible reactions. Durability test by sequential planting method indicated that this variety had better resistance. Results showed that Keumo3 was incompatible against 19 blast isolates with the exception of KI101 by artificial inoculation. To understand the genetic control of blast resistance in rice cultivar Keumo3 and facilitate its utilization, recombinant inbred lines (RIL) consisting of 290 F5 lines derived from Akidagomachi/Keumo3 were analyzed and genotyped with Pizt InDel marker zt56591. The recombination value between the marker allele of zt56591 and bioassay data of blast nursery test was 1.1%. These results indicated that MAS can be applied in selecting breeding populations for blast resistance using zt56591 as DNA marker.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.328-336
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• 2013

This study was conducted to evaluate imported tomato $F_1$ cultivars as breeding materials for the resistance to Tomato yellow leaf curl virus (TYLCV) by molecular markers and bioassay. From marker genotyping and disease evaluation of 40 $F_1$ cultivars, most of the cultivars declared as TYLCV-resistance carried heterozygous marker genotype for the TYLCV resistance genes Ty-1, Ty-3, or Ty-3a, and showed low disease rates. Whereas, 4 of 5 $F_1$ cultivars declared as intermediate resistance showed marker genotype for susceptibility and disease rates ranged 18.1-33.3%. However, the xx cultivars showed inconsistency in marker genotype and disease rate. Characterization of horticultural traits of the $F_1$ cultivars with TYLCV-resistance indicated that large-size fruit cultivars were higher in yield and similar in sugar contents and solid-acid ratio compared to a control cultivar preferred in the domestic market, although hardness remained to be a problem. On the other hand, cherry tomato cultivars showed lower yield and brix, but longer internode compared to a control cultivar, indicating that breeding for TYLCV-resistance using these cultivars will require more efforts and time compared to large-sized.

• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.284-289
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• 2015

Powdery mildew (Podosphaera xanthii) commonly occurs in cultivated fields of melon (Cucumis melo L.). It inflicts a lot of damages. Therefore, breeding resistant lines is essential. Development of a resistant line by integrating resistance gene takes a long time. In addition, break down of developed resistance by generating new virulent fungus strains increases disease susceptibility. This phenomenon was related to races of powdery mildew. Therefore, it is important to develop a DNA marker to genetically analyze race-specific resistance genes of melon powdery mildew to breed resistant lines. To date, a total of 28 races of Podosphaera xanthii have been reported in the literature. In Japan, 10 races have been reported in the Ibaraki region. We developed a system to characterize the races of Podosphaera xanthii and confirmed eight out of those 10 races in the Ibaraki region. In Korea, only one race has been characterized to date. However, some different races were detected. Through genetic analysis of resistant lines and susceptible lines of powdery mildew, resistance genes of race1 (Pm-X, PXB, and Pm-R 1), race N1 (PXA), race 2 (Pm-w and Pm-R 2), race 3 (Pm-X3), and race 5 (Pm-X5 and Pm-R5) were identified in melon. These related genes of race 1, 3, N1, 5, and race 1, 2, 5 were located at linkage group II and V, respectively. In race 1, resistance gene was located in the linkage group XII. In addition, each race-specific marker related to specific resistance gene was developed. Using race information and race selection system obtained in this study, resistant line can be bred to develop resistant cultivar for several areas. Furthermore, this will make it more easily and economically to breed resistant lines by using selected markers.

• The Plant Pathology Journal
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• v.40 no.5
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• pp.451-462
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• 2024

Xanthomonas oryzae pv. oryzae (Xoo) is a pathogenic bacterium responsible for bacterial blight (BB) disease in rice, primarily mediated by the interaction between the plant and pathogen. The virulence mechanism involves the activation of the Sugars Will Eventually be Exported Transporter (SWEET) gene family in rice by transcription activator-like effectors derived from Xoo. The BB resistance gene xa5 has been identified as one of the most effective genes against Thai Xoo isolates, but xa5-mediated resistance-breaking Xoo strains have emerged. This study aimed to develop a single nucleotide polymorphism (SNP) marker for precise identification of xa5-mediated resistance-breaking Xoo. Comparative genomics of Thai Xoo isolates Xoo16PK001 and Xoo16PK002, which were incompatible and compatible with rice variety IRBB5 carrying xa5, respectively, identified eight SNP positions for the development of an SNP marker. The SNP marker XooE6 yields a specific 1,143 bp PCR product unique to Xoo16PK002. Screening 61 Thai isolates using XooE6 identified two positives: Xoo20PL010 and Xoo20UT002. Inoculation tests on rice varieties IRBB5 and IRBB13 demonstrated compatibility with IRBB5 and incompatibility with IRBB13, which bears Xa5 and xa13. Xoo16PK001 (XooE6-negative) showed different virulence. Inoculation on IRBB21 harboring Xa5, Xa13, and Xa21 resulted in partial resistance to both XooE6-positive and -negative strains. XooE6-positive strains up-regulated SWEET11 and suppressed SWEET14 in IRBB5, while Xoo16PK001 slightly induced SWEET11 but activated SWEET14 in IRBB13. This highlights the potential of XooE6 to identify xa5-mediated resistance-breaking Xoo strains and elucidate their pathogenic mechanisms through the upregulation of SWEET11.

• Journal of Life Science
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• v.13 no.4
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• pp.375-382
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• 2003

A direct and precise explanation of soybean resistance to soybean cyst nematode will be possible only when the individual gene(s) involved in the resistance are tagged. This study was conducted, (1) to identify and localize quantitative trait loci for resistance to soybean cyst nematode race 14 on RAPD map, (2) to identify the magnitude and mode of inheritance for each quantitative trait loci, and (3) to identify the best combinations of quantitative trait loci for resistance to soybean cyst nematode race 14. Thirty markers (29 RAPD and 1 RFLP) showed significant association with resistance to soybean cyst nematode race 14. From MAPMAKER/QTL analysis, we identified two regions (linkage group C-7 and linkage group C-9) for resistance to soybean cyst nematode .ace 14. The first quantitative trait loci that was localized at 6.0 cM from $H06^1$ on linkage group C-7 showed a dominant inheritance mode. However, we can not exclude the possibility of additive inheritance mode. The second quantitative trait loci that was localized between $B15^2$ and $E01^1$ on linkage group C-9 also showed a dominant mode of inheritance. One pair of flanking markers ($H06^1$ and $H06^2$) and B15$^2$ were used for multiple regression analysis. Marker combination that included 2 markers, $B15^2$ and $H06^1$, explained the highest total variance (22.9%) for resistance to soybean cyst nematode race 14. Further localization of genes for resistance to soybean cyst nematode race 14 and examination of interaction between quantitative trait loci will accelerate the exploitation of resistance to soybean cyst nematode.

• Molecules and Cells
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• v.40 no.1
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• pp.54-65
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• 2017

Although cancer/testis antigen DDX53 confers anti-cancer drug-resistance, the effect of DDX53 on cancer stem cell-like properties and autophagy remains unknown. MDA-MB-231 ($CD133^+$) cells showed higher expression of DDX53, SOX-2, NANOG and MDR1 than MDA-MB-231 ($CD133^-$). DDX53 increased in vitro self-renewal activity of MCF-7 while decreasing expression of DDX53 by siRNA lowered in vitro self-renewal activity of MDA-MB-231. DDX53 showed an interaction with EGFR and binding to the promoter sequences of EGFR. DDX53 induced resistance to anti-cancer drugs in MCF-7 cells while decreased expression of DDX53 by siRNA increased the sensitivity of MDA-MB-231 to anti-cancer drugs. Negative regulators of DDX53, such as miR-200b and miR-217, increased the sensitivity of MDA-MB-231 to anti-cancer drugs. MDA-MB-231 showed higher expression of autophagy marker proteins such as ATG-5, $pBeclin1^{Ser15}$ and LC-3I/II compared with MCF-7. DDX53 regulated the expression of marker proteins of autophagy in MCF-7 and MDA-MB-231 cells. miR-200b and miR-217 negatively regulated the expression of autophagy marker proteins. Chromatin immunoprecipitation assays showed the direct regulation of ATG-5. The decreased expression of ATG-5 by siRNA increased the sensitivity to anti-cancer drugs in MDA-MB-231 cells. In conclusion, DDX53 promotes stem cell-like properties, autophagy, and confers resistance to anti-cancer drugs in breast cancer cells.