• The Plant Pathology Journal
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• v.28 no.1
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• pp.68-74
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• 2012

Biocontrol microbes have mainly been screened among large collections of microorganisms $via.$ nutrient-rich $in$ $vitro$ assays to identify novel and effective isolates. However, thus far, isolates from only a few genera, mainly spore-forming bacilli, have been commercially developed. In order to isolate field-effective biocontrol microbes, we screened for more than 200 oligotrophic bacterial strains, isolated from rhizospheres of various soil samples in Korea, which induced systemic resistance against the soft-rot disease caused by $Pectobacterium$ $carotovorum$ SCC1; we subsequently conducted in $planta$ bioassay screening. Two oligotrophic bacterial strains were selected for induced systemic disease resistance against the $Tobacco$ $Mosaic$ $Virus$ and the gray mold disease caused by $Botrytis$ $cinerea$. The oligotrophic bacterial strains were identified as $Pseudomonas$ $manteilii$ B001 and $Bacillus$ $cereus$ C003 by biochemical analysis and the phylogenetic analysis of the 16S rRNA sequence. These bacterial strains did not exhibit any antifungal activities against plant pathogenic fungi but evidenced several other beneficial biocontrol traits, including phosphate solubilization and gelatin utilization. Collectively, our results indicate that the isolated oligotrophic bacterial strains possessing induced systemic disease resistance could provide useful tools as effective biopesticides and might be successfully used as cost-effective and preventive biocontrol agents in the field.

• Molecules and Cells
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• v.28 no.1
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• pp.57-65
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• 2009

CDC48 is a member of the AAA ATPase superfamily. Yeast CDC48 and its mammalian homolog p97 are implicated in diverse cellular processes, including mitosis, membrane fusion, and ubiquitin-dependent protein degradation. However, the cellular functions of plant CDC48 proteins are largely unknown. In the present study, we performed virus-induced gene silencing (VIGS) screening and found that silencing of a gene encoding a tobacco CDC48 homolog, NgCDC48, resulted in severe abnormalities in leaf and shoot development in tobacco. Furthermore, transgenic tobacco plants (35S:anti-NgCDC48), in which the NgCDC48 gene was suppressed using the antisense RNA method, exhibited severely aberrant development of both vegetative and reproductive organs, resulting in arrested shoot and leaf growth and sterile flowers. Approximately 57-83% of 35S:anti-NgCDC48 plants failed to develop mature organs and died at early stage of development. Scanning electron microscopy showed that both adaxial and abaxial epidermal pavement cells in antisense transgenic leaves were significantly smaller and more numerous than those in wild type leaves. These results indicate that NgCDC48 is critically involved in cell growth and development of tobacco plants. An in vivo targeting experiment revealed that NgCDC48 resides in the endoplasmic reticulum (ER) in tobacco protoplasts. We consider the tantalizing possibility that CDC48-mediated degradation of an as-yet unidentified protein(s) in the ER might be a critical step for cell growth and expansion in tobacco leaves.

• Journal of Life Science
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• v.28 no.5
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• pp.555-562
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• 2018

Swine influenza virus (SIV) causes one of the most common diseases of the pig population, and its subtypes are determined by hemagglutinin (HA) and neuraminidase (NA). Recently, the SIV subtype diagnosis has been developed. The method using antigen-antibody reaction rather than PCR was mainly used because of the large change in the ribonucleotide sequences of SIV. Here, we have developed 10 diagnostic primer sets through multi-nucleotide sequences alignment of spreaded SIV since 2008 in Korea and then optimized the reaction of the one-step RT-PCR for rapid determination of SIV subtype. In addition, specific primers were designed to early determine the pandemic SIV by detecting unique M sequences proven in highly infectious and virulent subtypes of the influenza H1N1 (pH1N1). Here, some of the SIVs spread in Korea from 2008 to 2014 have been tested to determine the subtypes and pandemic potential of SIV. All diagnostic primer sets were found to be able to accurately determine the SIV subtype and to detect the pandemic SIV. In conclusion, it was confirmed that the optimized one-step RT-PCR analysis using these primer sets is useful for rapid diagnosis of SIV subtypes. These results can be used for development of SIV subtype diagnostic kit to early detect before virulent SIV spreads do.

• Journal of Ginseng Research
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• v.47 no.2
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• pp.329-336
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• 2023

Background: Panax ginseng Meyer is a medicinal plant well-known for its antiviral activities against various viruses, but its antiviral effect on coronavirus has not yet been studied thoroughly. The antiviral activity of Korean Red Ginseng (KRG) and ten ginsenosides against Human coronavirus OC43 (HCoV-OC43) was investigated in vitro. Methods: The antiviral response and mechanism of action of KRG extract and ginsenoside Rc, Re, Rf, Rg1, Rg2-20 (R) and -20 (S), Rg3-20 (R) and -20 (S), and Rh2-20 (R) and -20 (S), against the human coronavirus strain OC43 were investigated by using plaque assay, time of addition assay, real-time PCR, and FACS analysis. Results: Virus plaque formation was reduced in KRG extract-treated and HCoV-OC43-infected HCT-8 cells. KRG extract decreased the viral proteins (Nucleocapsid protein and Spike protein) and mRNA (N and M gene) expression, while increased the expression of interferon genes. Conclusion: KRG extract exhibits antiviral activity by enhancing the expression of interferons and can be used in treating infections caused by HCoV-OC43.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.31-36
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• 2016

Chlorine dioxide has been used for a disinfectant by exhibiting antimicrobial activity and is also potent to kill insect pests infesting stored grains. This study aimed to extend the usefulness of chlorine dioxide with respect to anticancer and antiviral activities. Cytotoxicity of chlorine dioxide was assessed against five different human cancer cell lines. Chlorine dioxide exhibited significant cytotoxicity against two breast cancer cell lines (MCF-7, MDA-MB-231) and three colorectal cancer cell lines (LoVo, HCT-116, SW-480). This cytotoxicity appeared to be associated with the capacity of chlorine dioxide to induce the production of reactive oxygen species (ROS). Compared to control insect cell lines, the cancer cell lines possessed much higher levels of ROS. On the other hand, a treatment of an antioxidant, vitamin E, significantly reduced the cytotoxicity, suggesting that the cytotoxicity was induced by high levels of ROS production. Chlorine dioxide exhibited antiviral activity against different viruses. A baculovirus, Autographa californica nuclear polyhedrosis virus (AcNPV), is a dsDNA insect virus and lost its viral activity to form polyhedral viral particles in response to chlorine dioxide. The antiviral activity against AcNPV was dependent on the incubation time with chlorine dioxide. Tobacco mosaic virus is a ssRNA plant virus and was reduced in its population after exposure to chlorine dioxide along with significant decrease of viral symptoms. These results indicate that chlorine dioxide possesses anticancer and antiviral activities probably due to its inducing activity of ROS production.

• Molecules and Cells
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• v.26 no.5
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• pp.496-502
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• 2008

Cryparin, encoded as a single copy gene (Crp) of the chestnut blight fungus Cryphonectria parasitica, is the most abundant protein produced by this fungus. However, its accumulation is decreased remarkably in C. parastica strains containing the double-stranded (ds) RNA virus Cryphonectria hypovirus 1. To characterize the transcriptional regulatory element(s) for strong expression and viral regulation, promoter analysis was conducted. Serial deletion of the Crp promoter region resulted in a step-wise decrease in promoter activity, indicating a localized distribution of genetic elements in the cryparin promoter. Promoter analysis indicated two positive and a repressive cis-acting elements. Among them, the promoter region between nt -1,282 and -907 appeared to be necessary for hypoviral-mediated down-regulation. An electrophoretic mobility shift assay (EMSA) on the corresponding promoter region (-1,282/-907) indicated two regions at (-1,257/-1,158) and (-1,107/-1,008) with the characteristic AGGAGGA-N42-GAGAGGA and its inverted repeat TCCTCTC-N54-TCCTCCT, respectively, appeared to be specific binding sites for cellular factors.

• Korean Journal of Plant Tissue Culture
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• v.25 no.6
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• pp.519-524
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• 1998

A simple and reliable method to diagnose cucumber green mottle mosaic virus of watermelon in Korea (CGMMV-WK) was determined by RT-PCR, and coat protein gene for CGMMV-WK was cloned. Comparing to a method reported by Lee et al. (1996), the method developed here showed a better RT-PCR reaction. RT-PCR was possible by one step in the PCR reaction mixture that contains 20 pmol of primer, reverse transcriptase (30 unit), RNasin (5 unit) using the crude RNA solution. RT-PCR condition for specifically diagnosing CGMMV-WK was that cDNA was synthesized at 42$^{\circ}C$ for 45 min followed by pre-denaturation at 95$^{\circ}C$ for 2 min, and then PCR reaction was carried out with a programmed condition that consisted of 36 sequential cycles at 96$^{\circ}C$ for 30 sec, 6$0^{\circ}C$ for 30 sec, and 72$^{\circ}C$ for 1 min. A gene encoding the coat protein of CGMMV-WK was cloned and characterized. Nucleotide sequence of coat protein gene of CGMMV-WK shared 98.77% and 99.38% of sequence identity with those of CGMMV-W and CGMMV-SH, respecitvely, however, all of amino acid sequences were same.

• Research in Plant Disease
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• v.25 no.1
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• pp.8-15
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• 2019

Plum pox virus (PPV) is a significant viral disease in Prunus spp. worldwide. A nationwide survey was started in Prunus spp. orchards, since PPV was first detected from peach in Korea, 2015. During 2016-2017, samples were collected from 30,333 trees in 1,985 orchards of stone fruits in 8 provinces and 4 cities, Korea and tested by RT-PCR using specific PPV primer set. As a result, 21 trees including peach (9 trees), Japanese apricot (4 trees), plum (1 tree), apricot (7 trees) in 10 orchards were infected and controlled by eradication program. Amplicons of the expected size (547 bp) were obtained from total RNA of seven peach trees in 2016, and directly sequenced. BLAST analysis revealed the highest nucleotide (NT) identity (99%) with a PPV D isolates (LC331298, LT600782) in Genbank. The seven isolates from shared nt sequence identities of 98 to 100% with one another. Phylogenetic analysis showed the isolates in peach clustered closely with the PPV-D isolates from Korea, Japan, USA, and Canada. This is, to our knowledge, the first report of the presence of PPV in Prunus spp. orchards in Korea, 2016-2017, we hope that our results and efforts will contribute to effective measures for eradication of PPV.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.11-17
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• 2007

Previously developed transgenic watermelon rootstocks (gongdae) inserted by CGMMV-CP were examined to test the virus tolerance levels. In the restricted plastic house, the $T_{3}$ watermelon rootstock showed tolerance to CGMMV until 70 days after inoculation on the leaves while the non-transformed watermelon rootstock became susceptible at 20 days after inoculation. In the field, tolerance efficiency of transgenic rootstocks maintained up to 40% at 71 days after contamination with CGMMV in the soil while all of the non-transformed rootstocks became susceptible at 37 days with the same condition. In the same field, transgenic rootstocks showed more tolerance to CGMMV than the non-transformed rootstocks as those were inoculated on the leaves, but it showed only 10 days delay before being susceptible. Therefore, transgenic rootstocks have a characteristic of delay effect against CGMMV susceptibility, rather than resistance character. From $T_{3}$ rootstocks homozygous for the CGMMV-CP horticulturally favorable individuals were selected for further breeding and a transgenic line was finally obtained at the $BC_{1}T_{5}$. A material transfer experiment was conducted to find out if the DNA, RNA or expressed protein in the transgenic rootstocks could move to the grafted scion (non-transformed watermelon, Super-Kumcheon). PCR, northern, and western blot analysis were performed and no evidence of transferring of those materials from rootstock to scion was ever found.

• Korean Journal of Medicinal Crop Science
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• v.17 no.2
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• pp.133-138
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• 2009

Nelumbo nucifera (lotus) is known to be a useful medicinal plant and leaf extract contains several flavonoids and alkaloids. To analyze the effect of Nelumbo nucifera leaves extract (NNL) on the HBsAg production, we treated NNL on HepG2.2.15 cells which contain the hepatitis B viral genome and secrete surface antigen into media. NNL suppressed the production of hepatitis B surface antigen as a dose-dependent manner. To analyze the effect of NNL on HBV DNA replication, PCR analysis was performed. NNL was not affected the HBV DNA replication and HBsAg mRNA expression. To understand the effect of NNL on the production of HBsAg, we carried out the analysis of lipid-metabolizing gene expression using one-step RT-PCR. NNL reduced the gene expression of FASN and SREBP2 and increased the expression of LDLR. Triglyceride content of HepG2.2.15 cells was not decreased by treatment of NNL. This result suggests a possibility that NNL may have an effect for the inhibition of hepatitis B surface antigen by modulation of lipid and cholesterol metabolism.