• Mycobiology
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• v.45 no.3
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• pp.160-171
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• 2017

Larvae of Bradysia agrestis, an insect vector that transports plant pathogens, were sampled from geographically isolated regions in Korea to identify their cutaneous fungal and bacterial flora. Sampled areas were chosen within the distribution range of B. agrestis; each site was more than 91 km apart to ensure geographical segregation. We isolated 76 microbial (fungi and bacteria) strains (site 1, 29; site 2, 29; site 3, 18 strains) that were identified on the basis of morphological differences. Species identification was molecularly confirmed by determination of universal fungal internal transcribed spacer and bacterial 16S rRNA gene sequences in comparison to sequences in the EzTaxon database and the NCBI GenBank database, and their phylogenetic relationships were determined. The fungal isolates belonged to 2 phyla, 5 classes, and 7 genera; bacterial species belonged to 23 genera and 32 species. Microbial diversity differed significantly among the geographical groups with respect to Margalef's richness (3.9, 3.6, and 4.5), Menhinick's index (2.65, 2.46, and 3.30), Simpson's index (0.06, 0.12, and 0.01), and Shannon's index (2.50, 2.17, and 2.58). Although the microbial genera distribution or diversity values clearly varied among geographical groups, common genera were identified in all groups, including the fungal genus Cladosporium, and the bacterial genera Bacillus and Rhodococcus. According to classic principles of co-evolutionary relationship, these genera might have a closer association with their host insect vector B. agrestis than other genera identified. Some cutaneous bacterial genera (e.g., Pseudomonas) displaying weak interdependency with insect vectors may be hazardous to agricultural environments via mechanical transmission via B. agrestis. This study provides comprehensive information regarding the cutaneous microflora of B. agrestis, which can help in the control of such pests for crop management.

• The Plant Pathology Journal
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• v.28 no.3
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• pp.239-247
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• 2012

Phytoplasmas have been associated with more than 46 plant species in Korea. Several vegetables, ornamentals, fruit trees and other crop species are affected by phytoplasma diseases. Six 16Sr groups of phytoplasmas have been identified and these phytoplasmas are associated with 63 phytoplasma diseases. Aster yellows phytoplasmas are the most prevalent group and has been associated with more than 25 diseases in Korea. Jujube witches' broom, paulownia witches' broom and mulberry dwarf diseases cause economic losses to host trees throughout the country. So far, Korean phytoplasmas belong to six species of 'Candidatus Phytoplasma'; 'Ca. P. asteris', 'Ca. P. pruni$^*$', 'Ca. P. ziziphi', 'Ca. P. trifolii', 'Ca. P. solani$^*$' and 'Ca. P. castaneae'. The diseases are distributed throughout the country and most of them were observed in Gyeongbuk and Chonbuk provinces. At least four insect vectors; Cyrtopeltis tenuis, Hishimonus sellatus, Macrosteles striifrons and Ophiola flavopicta have been identified for phytoplasma transmission.

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.10a
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• pp.219-219
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• 2021

• Korean Journal of Organic Agriculture
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• v.21 no.1
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• pp.95-104
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• 2013

This research was performed to test the effects of oleic acid for the management of greenhouse whiteflies and tobacco whiteflies. Tobacco whiteflies, especially, are the vectors of tomato yellow leaf curl virus on tomato plants. Whiteflies are not only the vectors of various viruses but also the major insect pests that cause direct damages through sucking and induce sooty mold with their sweet dew on tomato plants. There are many eco-friendly management measures including the use of yellow sticky trap and natural enemies such as Eretmocerus eremicus and Amblyseius swirskii. However, these management measures have difficulties to implement in the greenhouse. Therefore, in this research, oleic acid was tested for its effect on the management of whiteflies at various concentrations of 1,000ppm, 2,000ppm, or 4,000ppm. As a result, treatments of 1,000ppm, 2,000ppm and 4,000ppm oleic acid showed the control value of 70%, 76% and 84%, respectively. In another test, treatments of 2,000ppm oleic acid, and control treatment of 1,5000ppm neem oil and 50ppm dinotefuran showed the control value of 82%, 75%, and 75%, respectively. Cost for one application of oleic acid and neem oil for 10a area would be 3,180 Won and 20,150 Won, respectively. As a result, it was assumed that the use of oleic acid would be a appropriate management measure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.533-536
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• 2019

Recombinant baculoviruses are widely used to express heterologous genes in cultured insect cells. Recombinant baculoviruses can serve as gene-transfer vectors for expression of recombinant proteins in a wide range of mammalian cell types. Baculovirus system has significant benefits in view of safety, large-scale, and high level of gene expression. In this study, baculoviral vectors which were reconstructed from pOPINEneo-3C-GFP vector, were recombined with cytomegalovirus (CMV) promoter, green fluorescent protein (GFP), and p53 with NcoI and XhoI. These recombinant vectors were infected with various cells and cell lines. The baculovirus vector thus developed was analyzed by comparing the metastasis and expression of the recombinant genes with conventional vectors. These results suggest that the baculovirus vector has higher efficiency in metastasis and expression than the control vector. This work was supported by a grant from Mid-Career Researcher Program(NRF-2016R1A2B4016552) through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning(MSIP).

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1683-1690
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• 2018

Accurate and rapid diagnosis of influenza infection is essential to enable early antiviral treatment and reduce the mortality associated with seasonal and epidemic infections. Immunochromatography is one of the most common methods used for the diagnosis of seasonal human influenza; however, it is less effective in diagnosing pandemic influenza virus. Currently, rapid diagnostic kits for pandemic influenza virus rely on the detection of nucleoprotein (NP) or hemagglutinin (HA). NP detection shows higher specificity and is more sensitive than HA detection. In this study, we time-dependently screened expression conditions, and herein report optimal conditions for the expression of recombinant nucleoprotein (rNP), which was 48 h after infection. In addition, we report the use of the expressed rNP in a rapid influenza diagnostic test (SGT i-flex Influenza A&B Test). We constructed expression vectors that synthesized rNP (antigen) of influenza A and B in insect cells (Sf9 cells), employed the purified rNP to the immunoassay test kit, and clearly distinguished NPs of influenza A and influenza B using this rapid influenza diagnostic kit. This approach may improve the development of rapid test kits for influenza using NP.

• The Plant Pathology Journal
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• v.36 no.3
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• pp.280-288
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• 2020

RNA interference (RNAi) has attracted attention as a promising approach to control plant viruses in their insect vectors. In the present study, to suppress replication of the rice stripe virus (RSV) in its vector, Laodelphax striatellus, using RNAi, dsRNAs against L. striatellus genes that are strongly upregulated upon RSV infection were delivered through a rice leaf-mediated method. RNAi-based silencing of peroxiredoxin, cathepsin B, and cytochrome P450 resulted in significant down regulation of the NS3 gene of RSV, achieving a transcriptional reduction greater than 73.6% at a concentration of 100 ng/μl and, possibly compromising viral replication. L. striatellus genes might play crucial roles in the transmission of RSV; transcriptional silencing of these genes could suppress viral replication in L. striatellus. These results suggest effective RNAi-based approaches for controlling RSV and provide insight into RSV-L. striatellus interactions.

• Entomological Research
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• v.48 no.5
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• pp.384-389
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• 2018

Aphis gossypii Glover is an important insect pest that functions as a viral vector and mediates approximately 45 different viral diseases. As part of a strategy for control of A. gossypii, we investigated the functions of genes using RNAi. To this end, a cDNA library was constructed for various genes and for selecting appropriate targets for RNAi mediated silencing. The cDNA library was constructed using the Gateway cloning system with site-specific recombination of bacteriophage ${\lambda}$. It was used to carry out single step cloning of A. gossypii cDNAs. As a result, a cDNA library with a titer of $8.4{\times}10^6$ was constructed. Since the sequences in this library carry att sites, they can be cloned into various binary vectors. This library will be of value for various studies. For later screening of selected genes, it is planned to clone the library into virus-induced gene silencing (VIGS) vectors, which makes it possible to analyze gene function and allow subsequent transfection of plants. Such transfection experiments will allow testing of RNAi-induced insecticidal activity or repellent activity to A. gossypii, and result in the identification of target genes. It is also expected that the constructed cDNA library will be useful for analysis of gene functions in A. gossypii.

• The Plant Pathology Journal
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• v.33 no.6
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• pp.554-560
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• 2017

After 20 years of steady increase, kiwifruit industry faced a severe arrest due to the pandemic spread of the bacterial canker, caused by Pseudomonas syringae pv. actinidiae (Psa). The bacterium penetrates the host plant primarily via natural openings or wounds, and its spread is mainly mediated by atmospheric events and cultural activities. Since the role of sucking insects as vectors of bacterial pathogens is widely documented, we investigated the ability of Metcalfa pruinosa Say (1830), one of the most common kiwifruit pests, to transmit Psa to healthy plants in laboratory conditions. Psa could be isolated both from insects feeding over experimentally inoculated plants, and from insects captured in Psa-infected orchards. Furthermore, insects were able to transmit Psa from experimentally inoculated plants to healthy ones. In conclusion, the control of M. pruinosa is recommended in the framework of protection strategies against Psa.

• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.1
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• pp.111-114
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• 2012

In previous studies we have shown that a sw17255 gene was expressed in hemocyte-specific tissues of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae). It was verified that the sw17255 core promoter region contains elements that regulate the expression of this gene in hemocyte tissue; the selected promoter region spans nucleotides -1 to -2,112 upstream of the start codon. Each of the luciferase reporter gene expression vectors under the control of 4 different kinds of promoter candidates, (-2,112/-1), (-1,640/-1), (-1,169/-1) and (-579/-1), and the control reporter plasmid DNA, were introduced into B. mori larval coelom by direct injection using a syringe. The promoter candidate [E] (-579/-1) showed more than 1.67 fold transcriptional activity compared to control promoter activity. Higher productivity of an expressed gene in the transgenic silkworm by this promoter combination could be achieved in the near future. The foreign recombinant protein could be easily harvested from the blood of the transgenic silkworm.