• Research in Plant Disease
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• v.19 no.2
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• pp.114-117
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• 2013

To facilitate their spread, plant viruses have developed several methods for dispersal including insect and seed transmission. While insect transmission requires virus stability against insect digestion, seed-transmitted viruses have to overcome barriers to entry into embryos. Bean pod mottle virus (BPMV) is transmitted through seed at levels typically below 0.1%, but co-infection with Soybean mosaic virus (SMV) enhanced the seed transmission rate of BPMV in one experiment. In contrast, the rate of SMV seed transmission was not affected by BPMV co-infection. In a second preliminary study, the rate of SMV transmission was lower in an isoline of Williams 82 that contained a null mutation for the Kunitz trypsin inhibitor gene than in Williams 82. In this preliminary study, we observed that factors such as protease inhibitor expression and dual infection may affect the frequency of seed transmission of BPMV and SMV.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.70-74
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• 2015

The current market size of insect industry in Korea is estimated at 300 million dollars and more than 500 local farms are related to many insect industry. One of the strong candidates for insect industry is Korean horn beetle, Allomyrina dichotoma. Early this year, we reported a viral disease extremely fatal to A. dichotoma larvae. While we were proceeding a nationwide investigation of this disease, it was informed that similar disease symptom has been occurred occasionally during past over 10 years. The symptom can be easily confused with early stage of bacterial infection or physiological damage such as low temperature and high humidity. A peroral infection with the purified virus to healthy larvae produced a result that only 21% of larvae survived and became pupae. Although some of the survived adult beetle was deformational, many of them had no abnormal appearance and even succeeded in mating. Later, these beetles were examined if they were carrying the virus, and all except one were confirmed as live virus carrier. This implies that these beetles may fly out and spread the disease to the nature. We found the evidence for this possibility by collecting a few wild A. dichotoma larvae which were virus infected, near two local farms rearing A. dichotoma larvae. So far, transovarial transmission of this virus to the eggs, or horizontal transmission to other commercially reared insects is not known yet.

• The Plant Pathology Journal
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• v.23 no.2
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• pp.57-61
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• 2007

Whitefly-transmitted geminiviruses (WTGs) are economically important pathogens causing serious damage on tomato and chilli pepper in Indonesia. Geminiviruses are readily transmitted by its insect vector, sweetpotato whitefly (Bemisia tabaci). However, greenhouse whitefly (Trialeurodes vaporariorum), another species of whitefly, is commonly found together with B. tabaci in the field. Incidence of yellow leaf curl disease in tomato and chilli pepper is probably correlated with the population of whitefly complex. It is becoming important to find the role of T. vaporariorum in the spread of the disease. Therefore, research is conducted to study the characteristic relationship between tomato leaf curl begomovirus (ToLCV) and two species of whitefly. The two species of whitefly, B. tabaci and T. vaporariorum, was capable to transmit ToLCV although it was evidenced that B. tabaci is more effective as insect vector of ToLCV in tomato and chilli pepper. A single B. tabaci was able to transmit ToLCV to tomato with a minimum acquisition and inoculation access period of 10 h. Transmission of ToLCV by T. vaporariorum required at least 10 insects per plant with a minimum acquisition and inoculation access period of 24 h. The transmission efficiency will increase with longer acquisition and inoculation access period of the insect and the higher number of insect per plant.

• The Plant Pathology Journal
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• v.37 no.5
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• pp.437-445
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• 2021

Tilletia laevis Kuhn (syn. Tilletia foetida (Wallr.) Liro.) causes wheat common bunt, which is one of the most devastating plant diseases in the world. Common bunt can result in a reduction of 80% or even a total loss of wheat production. In this study, the characteristics of T. laevis infection in compatible wheat plants were defined based on the combination of scanning electron microscopy, transmission electron microscopy and laser scanning confocal microscopy. We found T. laevis could lead to the abnormal growth of wheat tissues and cells, such as leakage of chloroplasts, deformities, disordered arrangements of mesophyll cells and also thickening of the cell wall of mesophyll cells in leaf tissue. What's more, T. laevis teliospores were found in the roots, stems, flag leaves, and glumes of infected wheat plants instead of just in the ovaries, as previously reported. The abnormal characteristics caused by T. laevis may be used for early detection of this pathogen instead of molecular markers in addition to providing theoretical insights into T. laevis and wheat interactions for breeding of common bunt resistance.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.490-494
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• 2011

Rice stripe virus (RSV) has been the main viral disease of rice plant in western coastal region of Korea since 2000. The control of the vector insect, small brown planthopper (Laodelphax striatellus), is the most effective management method of the persistently-transmitted viral disease. Thus, ecological study between RSV and the vector insect was needed and investigated in order to make effective control plan, especially about study on the feeding and transmission of the virus by the vector insect. Each larval stage of vector insect differed in vector competence; larvae over 4th stage were shown as higher transmission after feeding on RSV-infected rice plant. These 4th and 5th larvae had higher transmission rates, 69.2% and 67.9% respectively, than 44.8% of the adult stage. The vector competence, however, was changed according to temperature; the highest transmission rate was 93.3% on $30^{\circ}C$ in comparison to 70.6% on $25^{\circ}C$ and 43.8% on $20^{\circ}C$.

• Korean Journal of Microbiology
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• v.4 no.2
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• pp.19-21
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• 1966

For the purpose of determining possibility of aphid-transmission of mosaic disease of black locust, cowpea aphid (Aphis medicagnis Koch) and green peach aphid (Myzus persicae Sulzer) were experimented using cowpea as test plant, and both proved to be the vectors. As for transmission threshold period of cowpea aphid to the virus, the acquisition feeding period was five seconds and inoculation feeding period was two minutes. This black locust mosaic virus, therefore, is a nonpersistent virus.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.635-639
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• 2012

The present study was initiated to find out the insect vector of mulberry dwarf phytoplasma. Among the collected insects from mulberry cultivation region, the sucking insects (Hishimonas sellatus, Bothrogonia japonica and Balclutha punctata) were selected for transmission of mulberry dwarf phytoplasma. Sucking insects, H. sellatus and B. punctata successfully transmitted phytoplasma to healthy seedling mulberry and periwinkle plants by inoculation-feeding. Typical dwarf symptom was observed in mulberry tree, but very slender twigs on stem and formatted small leaves were found on periwinkle plants, which are typical witches' broom symptoms. The phytoplasmas were detected in all samples exception sucking insects B. japonica using phytoplasma universal primer pair R16F2n/R2.

• Journal of Plant Biology
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• v.6 no.2
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• pp.9-21
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• 1963

A mosaic diseased radish collected from the suburb of Seoul, in November, 1961 was used for studing the host range, physical properteis, purificaitiion, insect transmission, and electron microscopy. A Japanese strain of radish mosaic(RPV) was also used with Korean strain of radish mosaic (KRMV) for a comparative study. The two viruses, KRMA and RPV, were identified by the difference in host range, insect transmission and electron microscopy. The KRMA was severely infective on tobacco and Nicotiana glutinosa, while on Gomphrena globsa was immune to the virus. RPV produces necrotic local lesions on Gomphrena globosa but did not infect tobacco and N. glutinosa. Among varieties of radish, Seoul, Akamaroo, Akanagea, Koong-Joong showed more severe symptoms than Simoo, Minong, Paek-soo, which appeared to be fainly resistant. In a number of tests, it was found that the virus KRMA retained its infectivity until to a dilution of 1:2,000, heating at $58^{\circ}$ for 10 minutes, adn aging in vitro for 7 days at room temperature. The RPV was not inactivated until it was diluted to 1:2,000, heated to $56^{\circ}$, and aged for 6 days. The KRMV was readily transmitted by the aphid(Myzus persicae Sulz). The virus RPV was not transmitted by the aphid in a number of tests. Partialy purified viruses using ammonium acetate buffer, salting-out by ammonium sulfate and centrifugation of high and low speed were highly infective. Electron micrographs showed that the KRMV paticles are of spherical particles whereas the RPV particles are rod-shaped.

• Journal of Plant Biology
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• v.6 no.2
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• pp.7-7
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• 1963

A mosaic diseased radish collected from the suburb of Seoul, in November, 1961 was used for studing the host range, physical properteis, purificaitiion, insect transmission, and electron microscopy. A Japanese strain of radish mosaic(RPV) was also used with Korean strain of radish mosaic (KRMV) for a comparative study. The two viruses, KRMA and RPV, were identified by the difference in host range, insect transmission and electron microscopy. The KRMA was severely infective on tobacco and Nicotiana glutinosa, while on Gomphrena globsa was immune to the virus. RPV produces necrotic local lesions on Gomphrena globosa but did not infect tobacco and N. glutinosa. Among varieties of radish, Seoul, Akamaroo, Akanagea, Koong-Joong showed more severe symptoms than Simoo, Minong, Paek-soo, which appeared to be fainly resistant. In a number of tests, it was found that the virus KRMA retained its infectivity until to a dilution of 1:2,000, heating at $58^{\circ}$ for 10 minutes, adn aging in vitro for 7 days at room temperature. The RPV was not inactivated until it was diluted to 1:2,000, heated to $56^{\circ}$, and aged for 6 days. The KRMV was readily transmitted by the aphid(Myzus persicae Sulz). The virus RPV was not transmitted by the aphid in a number of tests. Partialy purified viruses using ammonium acetate buffer, salting-out by ammonium sulfate and centrifugation of high and low speed were highly infective. Electron micrographs showed that the KRMV paticles are of spherical particles whereas the RPV particles are rod-shaped.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1537-1543
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• 2006

A bacterial strain named HY-3 that produces a highly active extracellular protease was isolated from the digestive tract of a spider, Nephila clavata. The bacterium was a Gram-negative, oxidase-negative, catalase-positive, nonhalophilic, nitrate-reducing, facultative anaerobe. Transmission and scanning electron microscopies demonstrated that the isolate was non-spare-forming, straight, rod-shaped, and motile by peritrichous flagella. The G+C content of the DNA was 57.0 mol%. The isoprenoid quinone type was ubiquinone with 8 isoprene units (Q-8). The morphological and biochemical characteristics including the predominant fatty acid and phospholipids profiles placed the isolate HY-3 in the family Enterobacteriaceae. Further biochemical characterization and phylogenetic studies including determination of an almost complete 16S ribosomal DNA sequence suggested that the bacterium was closely related to the genus Serratia. DNA-DNA hybridization analysis revealed that this extracellular protease-producing strain belongs to Serratia proteamaculans, which is also known far its association with insects.