• The Plant Pathology Journal
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• 제28권2호
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• pp.164-171
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• 2012

Rice blast disease caused by Magnaporthe grisea (Hebert) Barr [teleomorph] is one of the most devastating diseases in rice plantation areas. Silicon is considered as a useful element for a large variety of plants. Rice variety MR219 was grown in the glasshouse to investigate the function of silicon in conferring resistance against blast. Silica gel was applied to soil while sodium silicate was used as foliar spray at the rates of 0, 60, 120, 180 g/5 kg soil and 0, 1, 2, 3 ml/l respectively. The treatments were arranged in a completely randomized design. Disease severity and silicon content of leaves were compared between the non-amended controls and rice plants receiving the different rates and sources of silicon. Silicon at all rates of application significantly (${\alpha}$ = 0.05) reduced the severity of disease with highest reduction (75%) recorded in treatments receiving 120 g of silica gel. SEM/EDX observations demonstrated a significant difference in weight concentration of silicon in silica cells on the leaf epidermis between silicon treated (25.79%) and non treated plants (7.87%) indicating that Si-fertilization resulted in higher deposition of Si in silica cells in comparison with non-treated plants. Application of silicon also led to a significant increase in Si contents of leaves. Contrast procedures indicated higher efficiency of silica gel in comparison to sodium silicate in almost all parameters assessed. The results suggest that mitigated levels of disease were associated with silicification and fortification of leaf epidermal cells through silicon fertilization.

• The Plant Pathology Journal
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• 제30권4호
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• pp.416-424
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• 2014

Sweet potato is grown extensively from tropical to temperate regions and is an important food crop worldwide. In this study, we established detection methods for 17 major sweet potato viruses using single and multiplex RT-PCR assays. To investigate the current incidence of viral diseases, we collected 154 samples of various sweet potato cultivars showing virus-like symptoms from 40 fields in 10 Korean regions, and analyzed them by RT-PCR using specific primers for each of the 17 viruses. Of the 17 possible viruses, we detected eight in our samples. Sweet potato feathery mottle virus (SPFMV) and sweet potato virus C (SPVC) were most commonly detected, infecting approximately 87% and 85% of samples, respectively. Furthermore, Sweet potato symptomless virus 1 (SPSMV-1), Sweet potato virus G (SPVG), Sweet potato leaf curl virus (SPLCV), Sweet potato virus 2 ( SPV2), Sweet potato chlorotic fleck virus (SPCFV), and Sweet potato latent virus (SPLV) were detected in 67%, 58%, 47%, 41%, 31%, and 20% of samples, respectively. This study presents the first documented occurrence of four viruses (SPVC, SPV2, SPCFV, and SPSMV-1) in Korea. Based on the results of our survey, we developed multiplex RT-PCR assays for simple and simultaneous detection of the eight sweet potato viruses we recorded.

• Mycobiology
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• 제48권3호
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• pp.233-239
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• 2020

A small-spored Alternaria was found from black spots of storaged Koerle pear (Pyrus sinkiangensis), one of the economically important fruit in Xinjiang province, China. The morphology is similar to A. limoniasperae but obviously different in secondary conidiophores and conidial septa. A phylogenetic analysis using sequence datasets of ITS, GAPDH, TEF1, RPB2, Alt a1, OPA10-2, and EndoPG genes revealed that it belonged to the Alternaria alternata complex group. Pathogenicity tests illustrated that the fungus was the causal pathogen of black spot on Koerle pear fruit.

• Research in Plant Disease
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• 제18권2호
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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.

• Research in Plant Disease
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• 제26권4호
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• pp.239-249
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• 2020

To find out the cause of the fire blight outbreak in apples and pears of Korea in 2019, we investigated disease appearing situation of thirty fire blight infected orchards, and interviewed farmers to determine the cultivation characteristics. Fire blight occurred mostly in orchards that had infected more than 2 years before. The cause of this were as follows: farmers did not know the symptoms of the disease properly. It is presumed that it has spread from the first occurrence to the surrounding orchards by flower-visiting insects or farmers and to a short distance or a long distance by the same cultivator or co-farmer. These series of processes repeated in the newly spreading area, and then disease reports increased as farmers became aware of fire blight. To minimize the spread of fire blight in Korea, it suggested that thorough education of farmers for early diagnosis and quantitative detection technology that can diagnose even in no symptom showing plants. And chemical or biological spraying systems suitable for domestic cultivation methods, which are producing large fruits, and molecular epidemiological studies of pathogens.

• Research in Plant Disease
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• 제19권4호
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• pp.331-337
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• 2013

A disease, supposedly caused by a virus, was observed from Insam (Panax ginseng) fields of Punggi in year 2006. It has long believed to be a physiological disorder. However, the incidence of the disease has increased every year. When several samples were observed under electron microscope, filamentous virus-like particles were observed. The nucleotide sequences of the virus were analyzed by RT-PCR with specific primer sets derived from the results of DNA chip. The results indicated that the disease was caused by Watermelon mosaic virus (WMV). It revealed that the result of the biological assay by the virus was different from that of WMV previously found in other crops. Therefore, this is the first report that WMV causes the disease in P. ginseng and the virus is named to be WMV-Insam.

• The Korean Journal of Pesticide Science
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• 제7권3호
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• pp.223-227
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• 2003

Survey on plant diseases occurring on cucumber cultivated in plastic film house of experimental farm in Suwon was conducted. Through the survey, occurrence of damping-off, downey mildew, powdery mildew and Fusarium wilt was observed. Especially downey mildew caused by Pseudoperonospora cubensis was the most severe foliar disease of cucumber. To control the disease effectively, effects of installation of ventilation fan and optimal spray timing of a chemical, dimethomorph+copper oxychloride WP, were investigated. Two ventilation fans installed at the front and at the back of plastic film house reduced air relative humidity by about 6.4% and downey mildew incidence by 55.7%. Downey mildew incidence on cucumber from untreated chemicals plot in plastic film house installed with ventilation fan was on a equal level with that from treated chemicals plot with three times application of dimethomorph+copper oxychloride WP in plastic film house without ventilation fan. Meanwhile in order to select optimal chemical application time, dimethomorth+copper oxychloride WP was treated three times at 7 days-interval from three days before the disease occurred, right after the disease occurred, and two days after the disease occurred, respectively. The result showed that dimethomorth+copper oxychloride WP applied to cucumber leaves and stems from three days prior to, right after, two days after occurrence of downey mildew reduced downey mildew incidence by 72.9, 61.8, and 23.7%, respectively. The above results showed that regulation of environmental factors like air relative humidity and preventive application of chemicals should be considered to establish control strategy to downey mildew.

• Molecules and Cells
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• 제45권3호
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• pp.148-157
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• 2022

Hepatitis C virus (HCV) is a major cause of chronic liver disease and is highly dependent on cellular proteins for viral propagation. Using protein microarray analysis, we identified 90 cellular proteins as HCV nonstructural 5A (NS5A) interacting partners, and selected telomere length regulation protein (TEN1) for further study. TEN1 forms a heterotrimeric complex with CTC and STN1, which is essential for telomere protection and maintenance. Telomere length decreases in patients with active HCV, chronic liver disease, and hepatocellular carcinoma. However, the molecular mechanism of telomere length shortening in HCV-associated disease is largely unknown. In the present study, protein interactions between NS5A and TEN1 were confirmed by immunoprecipitation assays. Silencing of TEN1 reduced both viral RNA and protein expression levels of HCV, while ectopic expression of the siRNA-resistant TEN1 recovered the viral protein level, suggesting that TEN1 was specifically required for HCV propagation. Importantly, we found that TEN1 is re-localized from the nucleus to the cytoplasm in HCV-infected cells. These data suggest that HCV exploits TEN1 to promote viral propagation and that telomere protection is compromised in HCV-infected cells. Overall, our findings provide mechanistic insight into the telomere shortening in HCV-infected cells.

• Journal of Forest and Environmental Science
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• 제40권1호
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• pp.1-8
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• 2024

Recently, intensive research has been conducted to develop innovative methods for diagnosing plant diseases based on hyperspectral technologies. Hyperspectral analysis is a new subject that combines optical spectroscopy and image analysis methods, which makes it possible to simultaneously evaluate both physiological and morphological parameters. Among the physiological and morphological parameters are classifying healthy and diseased plants, assessing the severity of the disease, differentiating the types of pathogens, and identifying the symptoms of biotic stresses at early stages, including during the incubation period, when the symptoms are not visible to the human eye. Plant diseases cause significant economic losses in agriculture around the world as the symptoms of diseases usually appear when the plants are infected severely. Early detection, quantification, and identification of plant diseases are crucial for the targeted application of plant protection measures in crop production. Hence, this can be done by possible applications of hyperspectral sensors and platforms on different scales for disease diagnosis. Further, the main areas of application of hyperspectral sensors in the diagnosis of plant diseases are considered, such as detection, differentiation, and identification of diseases, estimation of disease severity, and phenotyping of disease resistance of genotypes. This review provides a deeper understanding, of basic principles and implementation of hyperspectral sensors that can measure pathogen-induced changes in plant physiology. Hence, it brings together critically assessed reports and evaluations of researchers who have adopted the use of this application. This review concluded with an overview that hyperspectral sensors, as a non-invasive system of measurement can be adopted in early detection, identification, and possible solutions to farmers as it would empower prior intervention to help moderate against decrease in yield and/or total crop loss.

• Korean Journal of Poultry Science
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• 제19권1호
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• pp.17-25
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• 1992

The efficacy of B$_1$l live vaccine which is used successfully in chicken was examined against Newcastle disease in quails. A total of 480 male quails were divided into 4 groups, of which 3 groups were vaccinated via drinking water, eye instillation and spraying method and the remaining was employed as a nonvaccinated control group. At 3 weeks after the first vaccination a part of quails in each group was revaccinated. Efficacy of the vaccine was evaluated by the antibody responses and the protection rates after challenge with a virulent NDV. Vaccination of quails with $B_1$ NDV at 10 days of age resulted in beneficial effect compared to nonvaccinated group regardness of vaccination methods adopted although general protection rates were considerably low. Twice vaccination gave higher protection than once vaccination. Hemagglutination inhibition antibody responeses were significantly higher in groups of quails vaccinated by spray and eye instillation method than by drinking water administration. Antibody responses were marked at 2 weeks onward and until 5 to 7 weeks after vaccination. Antibody responses were rapid and marked after second vaccination. However, antibody level did not last longer than 5 to 7 weeks postvaccination. Vaccine caused no adverse effect on quails in terms of growth'rate, body temperature or clinical signs.