• Research in Plant Disease
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• v.29 no.2
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• pp.130-136
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• 2023

Citrus melanoses caused by Diaporthe citri, has been one of the serious diseases in many citrus orchards of Jeju Island. To protect melanose in citrus farms, a fast and exact diagnosis method is necessary. In this study, diseased leaves and dieback twigs were collected from a total of 49 farms within March to April in 2022. A total of 465 fungal isolates were obtained from a total of 358 isolated plant samples. Among these fungal isolates, 40 representatives of D. citri isolates which were isolated from 22 twigs and 18 leaves on 23 farms were found based on cultural characteristics on potato dextrose agar and conidial morphology. Additionally, the molecular assay was carried out and compared with those by morphological diagnosis. All isolates were identified as D. citri by analyzing the sequences at the internal transcribed spacer (ITS) rDNA region using primers of ITS1/ITS4 or at β-tubulin using primer Btdcitri-F/R. Therefore, based on the present study, where the results of morphological identification of conidial type were consistent with DNA sequence analysis of certain gene, choosing a suitable method for a fast diagnosis of citrus melanose was suggested.

• Mycobiology
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• v.40 no.3
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• pp.189-194
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• 2012

Four Cladobotryum isolates were collected from four different commercially grown mushroom types infected with cobweb disease in Cheongdo-gun and Chilgok-gun of Gyeongbuk Province, Korea in 2010. The isolates were identified as C. mycophilum from Agaricus bisporus and Pleurotus eryngii, C. varium from Flammulina velutipes and Hypsizygus marmoreus. The cultural characteristics of the four isolates were investigated using potato dextrose agar (PDA) media under nine different temperatures ranging from $5{\sim}32^{\circ}C$. Rapid growth of the isolates to colony diameters of 47~82 mm was observed at conditions of $18{\sim}22^{\circ}C$. No growth was observed at $32^{\circ}C$. C. mycophilum produced a yellowish red pigment while C. varium produced a cream colored pigment after cultivation for 25 days on PDA. Phylogenetic analysis of the internal transcribed spacer region and partial 28S rDNA from the four isolates confirmed they were C. mycophilum and C. varium. Cross pathogenicity tests revealed that the two isolates of C. mycophilum were highly pathogenic toward three mushroom types, but not toward H. marmoreus. The two isolates of C. varium were less pathogenic than those of C. mycophilum, but were pathogenic toward all mushroom types evaluated.

• Research in Plant Disease
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• v.19 no.1
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• pp.49-54
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• 2013

Sclerotinia white rot disease was observed on 5 and 6-year-old ginseng (Panax ginseng) roots in Hongchun, Cheorwon, and Yanggu, Gangwon Province, Korea from 2006 to 2010. Symptoms included a brownish watery soft rot of the roots, and black sclerotia were often found on the rotten roots. The causal agent of the disease was identified as Sclerotinia nivalis based on cultural characteristics and sequence analyses of the internal transcribed spacer region of rDNA and ${\beta}$-tubulin gene with 100% sequence similarity. Pathogenicity tests were performed on 2-year-old ginseng roots with mycelium plugs without wounds. A watery soft rot of the roots and black sclerotia were observed 10 days after inoculation. These symptoms were identical to those observed on naturally infected roots. The same fungus was re-isolated from the lesions induced by artificial inoculation. This is the first report of sclerotinia white rot caused by S. nivalis on P. ginseng in Korea.

• The Korean Journal of Mycology
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• v.38 no.2
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• pp.112-119
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• 2010

Pleurotus spp. have been used for edible and medicinal purposes in Asian countries for a long time. The fruiting bodies of the Pleurotus ostreatus, Pleurotus citrinopileatus and Pleurotus salmoneostramineus contained many physiologically beneficial substances for human health. Therefore, it is necessary to study the genetic diversity of Pleurotus mushroom cultivars commercially cultivated in Korea. Eleven strains of Pleurotus spp. were collected from different geographical regions in South-East Asia and ITS regions of rDNA and RAPD of genomic DNA were analyzed. The size of the ITS1 and ITS2 regions of rDNA from the different strains varied from 167 to 254 bp and 156 to 213 bp, respectively. The sequence of ITS1 was more variable than that of ITS2, and the 5.8S sequences were identical. A phylogenetic tree based on the ITS region sequences indicated that selected strains could be classified into 4 clusters. Eleven Pleurotus species were also analyzed by RAPD with 20 arbitrary primers. Ten of these primers were efficiently amplified the genomic DNA. The number of amplified bands varied with the primers and strains, with polymorphic fragments in the range from 0.1 to 2.0kb. The results revealed that genetic diversity of selected strains of P. ostreatus, P. citrinopileatus and P. salmoneostramineus is low.

• Korean Journal of Microbiology
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• v.39 no.4
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• pp.272-276
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• 2003

Sapgyo Lake is an artificial freshwater reservoir which is located to the midwest of Korea and is the main water reservoir for industry and agriculture of the region. In this study we investigated environmental factors and the change of bacterial community with the influence of surrounding inflow water and the seasonal variation using the molecular ecological approach. Water samples were collected at front of the dike in May and August, 2001. Bacterial genomic DNAs were extracted directly and purified for the amplification of bacterial 16S rDNA. Clone libraries of the 16S rDNA were constructed using pGEM-T easy vector and RFLP analysis was performed to make a group as OTUs with 4 base recognizing enzymes (MspI and HaeIII). The estimated values of richness in August sample was higher than in May. Thirty-three of 153 clones in May and thirty-eight of 131 clones in August were sequenced from forward region of bacterial 16S rDNA for about 600~800 bp. Proteobacteria, Cytophaga, gram positive bacteria and Verrucomicrobia were observed both months. Especially, Planctomyces, cyanobacteria and chloroplast appeared in August when algal bloom occurred. On the whole investigation, Sapgyo lake showed a typical community structure of estuarine and was influenced by heterochthonous organic matters from the surrounding stream.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.658-665
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• 2011

An wild boar species which has been known as an extinct species on Jeju Island, was recently observed in the surrounding areas of Mount Halla. Based on the molecular techniques, this study examines whether they are crossbred with domesticated pig breeds. Intraspecific genetic relationships with other wild boar populations and molecular sexing were examined as well. Total of four molecular markers on mitochondrial DNA(control region and ND2) and nuclear DNA(MC1R and KIT) were applied to test crossbreeding between with domesticated pig breeds, such as Landrace, Large White, Berkshire, Hampshire, and Duroc. All individuals of wild boar population had identical mtDNA control region(CR) sequences. In addition, the sequences were the same as those of some native pig breeds which are distributed in Northeast China, but different from those previously reported from the Korean Peninsula up to date. These results suggest that this population may have originated from a genetic lineage had been not previously studied and genetically related to Chinese native pig breeds. Molecular sexing results show that there are twice as many females as male. Thus the population is under expansion and its size will dynamically increase if not controlled.

• Korean Journal of Medicinal Crop Science
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• v.17 no.1
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• pp.46-53
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• 2009

Schizonepeta spike (Korean name "Hyung-Gae") has been used for oriental medicinal purposes in Korea, China and Japan. In this study, twenty six "Hyung-Gae" samples were collected including nine certified Schizonepeta tenuifolia plants, and seventeen commercially marketed "Hyung-Gae" products. Chloroplast trnL-F and rDNA ITS regions of the "Hyung-Gae" samples were sequenced and used to identify whether the samples were genuine S. tenuifolia or not. As the result, the trnL-F and ITS sequences of all the "Hyung-Gae" samples were shown to be identical and it was proven that commercially available medicinal products "Hyung-Gae" are genuine S. tenuifolia. Phylogenetic tree of S. tenuifolia using the trnL-F sequences was constructed and compared with phylogenetic tree using ITS of rDNA region sequences. In these tree, S. tenuifolia was affiliated in the family Lamiaceae. It is proven that trnL-F and ITS phylogenetic trees are useful to study taxonomic position of S. tenuifolia.

• Research in Plant Disease
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• v.18 no.2
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• pp.73-79
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• 2012

Phytophthora katsurae is a fungal pathogen responsible for chestnut ink disease. We designed two duplex primer sets (SOPC 1F/1R+KatI 3F/5R, SOPC 1-1F/1-1R+KatI 3F/5R) to detect P. katsurae. SOPC 1F/1R and SOPC 1-1F/1-1R primer pairs were designed for sequence characteristic amplification regions (SCAR) marker, and KatI 3F/5R primer pair was used for P. katsurae-specific primer designed from internal transcribed spacer (ITS) region. To assess the sensitivity of duplex PCR, genomic DNA was serially diluted 10-fold to make the final concentrations from 1 mg/ml to 1 ng/ml. The sensitivity for two primer sets were 1 ${\mu}g/ml$ and 100 ng/ml, respectively. To find detection limits for zoospores of P. katsurae, each zoospore suspension was serially diluted 10-fold to make the final concentrations from $1{\times}10^6$ to $1{\times}10^2$ cells/ml, and then DNA was extracted. The limits of detection for all of two primer sets were $1{\times}10^5$ cells/ml. All of two primer sets were specific to P. katsurae in PCR detection and did not produce any P. katsurae-specific PCR amplicons from other 16 Phytophthora species used as the control. This study shows that duplex PCR using two primer sets might be a useful tool for rapid and efficient detection of P. katsurae.

• Korean Journal of Veterinary Research
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• v.31 no.3
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• pp.311-318
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• 1991

The DNA fragment representing for Pseudorabies gp50 and gp60(Shope) was cloned by recombinant techniques. The viral DNA was extracted from the infected cells and digested with Bam HI. The 6.8 Kb of Bam HI fragment was isolated from agarose gel and further digested with Nde I followed by Klenow treatment. The blunt ended 4.9Kb fragment was cloned into pTZ18R plasmid vector. The upstream region of gp50 was further manipulated to remove its 5' promoter region and create EcoRl site for possible eukaryotic expression system. The result of partial sequencing of cloned DNA indicated that Shope strain showed 95% homology with gp50 of Rice strain.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.43-43
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• 2018

Dumortiera hirsuta (Sw.) Nees (Dumortieraceae) is a thallose liverwort distributed in tropics and subtropics. It is the only species in family Dumortieraceae, which is the second basal family in order Marchantiales. D. hirsuta is characterized by hairy receptacles and lacking air chamber. The complete chloroplast genome of D. hirsuta was successfully rescued from raw reads generated by HiSeq4000. Its total length is 122,050 bp consisting of four regions: large single copy (LSC) region (81,697 bp), small single copy (SSC) region (20,061 bp), and two inverted repeats (IRs; 10,146 bp per each). It contained 129 genes (84 coding DNA sequence (CDS), eight rRNAs, and 37 tRNAs); 18 genes including four rRNAs, and five tRNAs are duplicated in the IR regions. The overall GC content of D. hirsuta is 28.7%, which is almost same to that of Marchantia paleacea. Phylogenetic tree based on all genes from whole chloroplast genomes will provides phylogenetic position of D. hirstua. This sequence will be an fundamental resources for further researches of order Marchantiales.