• Research in Plant Disease
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• 제9권1호
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• pp.52-56
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• 2003

It was conducted to investigate the effect of rice downy mildew (RDM) infection to plant growth and yield components in water seeding stage, and to screen of varietal resistance to downy mildew. Being infected by rice downy mildew, chlorotic spot appeared in the leaf and leaf length was shortened. As the infected rice was growing, internode was not elongated properly and was deformed, and then panicle was not arised or mal-formed. Plant height of infected rice was shortened at all growth stage, and while the number of tillers of infected rice was more decreased than that of healthy plant before maximum tillering stage, and that of infected rice was more increased after heading stage. While the number of internode of infected tiller was much increased than that of healthy tiller internode length of infected tiller was shorter. As the rice infected by RDM severely, the number of panicles per square meter and ripening of rice was more decreased and yield of rice was extremely much decreased. As result of the varietal resistance screening with rice seedling, Geyh-wabyeo and Donjinbyeo were resistant varieties to downy mildew.

• Korean Journal Plant Pathology
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• 제1권3호
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• pp.165-168
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• 1985

Ethanol-soluble amino acids in healthy and powdery mildew-infected leaves of the susceptible cultivar Peruvian and the adult-plant-resistant cultivar Asse of spring barley were quantitatively analysed. At I day after inoculation, the levels of amino acids in the infected first leaves of the two cultivars were similar to those of comparable healthy controls. During sporulation, increases in amino acids were more pronounced in Peruvian than those in Asse. The changes in amino acid content in the infected first and fifth leaves were closely related to the number of colonies per leaf. The susceptible cultivar Peruvian showed higher amounts of amino acids in infected first and fifth leaves at all infection intensitives than did Asse.

• The Plant Pathology Journal
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• 제24권1호
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• pp.31-35
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• 2008

The presence of Chrysanthemum stunt viroid (CSVd) in seed and pollen of diseased chrysanthemum was demonstrated. In seeds infected male parent from crosses in May, CSVd was transmitted to 6.7% of the progeny seedlings, whereas if the female parent was infected, CSVd transmission rate was between 46.9 and 75.7%. A relatively high incidence of 94.4 to 96.0% seed transmission occurred when both parents were infected. In seeds infected male parent from crosses in December, no progeny seedlings were infected with CSVd, whereas if the female parent did, CSVd transmission rate was 1.5%. When both parents were infected, 6.9% seed transmission was occurred. The seed transmission rate depended on the temperature when the crosses were made. CSVd was not detected in the non-infected female parent pollinated with infected pollen but was transmitted to the progenies. This is the first report of seed-borne transmission of CSVd in chrysanthemum.

• The Plant Pathology Journal
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• 제18권3호
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• pp.126-129
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• 2002

Infected sweet potato (Ipomoea batatas) showing symptoms of sunken veins, stunting, mosaic, and mottling were collected from Gimje, Cochang, Iksan, and Haenam provinces in Korea. Electron microscopic (EM) observation of the infected tissue revealed rod and filamentous rod type virus particles of various lengths. Western blot analysis of the protein samples extracted from infected sweet potato and partially purified virus identified the isolates as Sweet potato feathery motile virus (SPFMV), Sweet potato latent virus (SwPLV), and Sweet potato chlorotic stint virus (SPCSV). Sweet potatoes were occasionally infected with more than one of these viruses. This is the first report of SwPLV and SPCSV in Korea.

• Korean Journal Plant Pathology
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• 제13권4호
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• pp.239-243
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• 1997

In August 1996, phyllody disease of sesame (Sesamum indicum L.) caused by phytoplasmas was observed at Boeun, Chungbuk Province, Korea. Symptoms included extreme proliferation of growing tips and numerous small leaves, giving the infected plant a witche's-broom effect. Parts or all of the floral parts were transformed into green leaf-like structures, and little or no seeds were produced. Transmission Electron microscopy revealed the presence of phytoplasmas in the phloem sieve elements of infected plant. Since the infected sesame plants were growing near by phytoplasma infected jujubes (Zizyphus jujubu), we tried a polymerase chain reaction (PCR) technique to identify these two causal phytoplasmas. The DNA extracted from the stems of infected sesame plant was PCR-amplified using a primer set specific to 16S rRNA gene of known phytoplasmas. The amplification generated a 1.4kb band in both sesame samples and phytoplasma-infected jujubes, which also suggests the sesame plants were infected with phytoplasmas. The restriction digestion of the amplified band by four different enzymes, AluI, HaeIII, HinfI or TaqI revealed that the phytoplasmas infecting jujubes and sesame plants were of different groups.

• Journal of Veterinary Science
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• 제22권2호
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• pp.26.1-26.6
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• 2021

Fourteen African swine fever (ASF) outbreaks occurred in the pig farms in the northwestern region of South Korea, near the border with North Korea, from September 16, 2019 to October 9, 2019. Active and passive surveillance on the ASF-infected farms indicated that the infection was limited only to pigsties where the infected pigs were detected on the farm for the first time before further transmission to other pigsties and farms. This early detection could be one of the pivotal factors for the prompt eradication of ASF in domestic pig farms within 1 month in the northwestern region of South Korea.

• Journal of Biosystems Engineering
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• 제33권6호
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• pp.446-452
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• 2008

Machine vision system was used for analyzing leaf color disorders of tomato plants in a greenhouse. From the day when a few leave of tomato plants had started to wither, a series of images were captured by 4 times during 14 days. Among several color image spaces, Saturation frame in HSI color space was adequate to eliminate a background and Hue frame was good to detect infected disease area and tomato fruits. The processed image ($G{\sqcup}b^*$ image) by OR operation between G frame in RGB color space and $b^*$ frame in $La^*b^*$ color space was useful for image segmentation of a plant canopy area. This study calculated a ratio of the infected area to the plant canopy and manually analyzed leaf color disorders through an image segmentation for Hue frame of a tomato plant image. For automatically analyzing plant leave disease, this study selected twenty-seven color patches on the calibration bars as the corresponding to leaf color disorders. These selected color patches could represent 97% of the infected area analyzed by the manual method. Using only ten color patches among twenty-seven ones could represent over 85% of the infected area. This paper showed a proposed machine vision system may be effective for evaluating various leaf color disorders of plants growing in a greenhouse.

• The Plant Pathology Journal
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• 제39권2호
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• pp.207-219
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• 2023

Soft rot is a widespread, catastrophic disease caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) that severely damages the production of Amorphophallus spp. This study evaluated the rhizosphere bacterial and fungal communities in Pcc-infected and uninfected plants of two species of Amorphophallus, A. muelleri and A. konjac. Principal component analysis showed that the samples formed different clusters according to the Pcc infection status, indicating that Pcc infection can cause a large number of changes in the bacterial and fungal communities in the Amorphophallus spp. rhizosphere soil. However, the response mechanisms of A. muelleri and A. konjac are different. There was little difference in the overall microbial species composition among the four treatments, but the relative abundances of core microbiome members were significantly different. The relative abundances of Actinobacteria, Chloroflexi, Acidobacteria, Firmicutes, Bacillus, and Lysobacter were lower in infected A. konjac plants than in healthy plants; in contrast, those of infected A. muelleri plants were higher than those in healthy plants. For fungi, the relative abundances of Ascomycota and Fusarium in the rhizosphere of infected A. konjac plants were significantly higher than those of healthy plants, but those of infected A. muelleri plants were lower than those of healthy plants. The relative abundance of beneficial Penicillium fungi was lower in infected A. konjac plants than in healthy plants, and that of infected A. muelleri plants was higher than that of healthy plants. These findings can provide theoretical references for further functional research and utilization of Amorphophallus spp. rhizosphere microbial communities in the future.

• Korean Journal Plant Pathology
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• 제14권5호
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• pp.545-547
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• 1998

Scab disease of Aralia elata (Miq.) Seemann occurred severely in Kangwon province, Korea. First, brown spots were formed on leaves and enlarged along vein. The infected leaves including petiole and midrib were twisted forming scab and died eventually. Also the disease infected twigs and trunks of the tree forming scab. Conidia, ascospores and asci developed in locule were observed in the infected tissue. The causal organism of the scab disease of Araliae elata was isolated and identified as Elsinoe araliae Yamamoto (imperfect stage: Sphaceloma araliae Jenkins) based on the morphological and cultural characteristics, and pathogenic test.

• The Plant Pathology Journal
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• 제35권5호
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• pp.521-529
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• 2019

Tomato yellow leaf curl China virus is a species of the widespread geminiviruses. The infection of Nicotiana benthamiana by Tomato yellow leaf curl China virus (TYLCCNV) causes a reduction in photosynthetic activity, which is part of the viral symptoms. ${\beta}C1$ is a viral factor encoded by the betasatellite DNA ($DNA{\beta}$) accompanying TYLCCNV. It is a major viral pathogenicity factor of TYLCCNV. To elucidate the effect of ${\beta}C1$ on plants' photosynthesis, we measured the relative chlorophyll (Chl) content and Chl fluorescence in TY-LCCNV-infected and ${\beta}C1$ transgenic N. benthamiana plants. The results showed that Chl content is reduced in TYLCCNV A-infected, TYLCCNV A plus $DNA{\beta}$ (TYLCCNV A + ${\beta}$)-infected and ${\beta}C1$ transgenic plants. Further, changes in Chl fluorescence parameters, such as electron transport rate, $F_v/F_m$, NPQ, and qP, revealed that photosynthetic efficiency is compromised in the aforementioned N. benthamiana plants. The presense of ${\beta}C1$ aggravated the decrease of Chl content and photosynthetic efficiency during viral infection. Additionally, the real-time quantitative PCR analysis of oxygen evolving complex genes in photosystem II, such as PsbO, PsbP, PsbQ, and PsbR, showed a significant reduction of the relative expression of these genes at the late stage of TYLCCNV A + ${\beta}$ infection and at the vegetative stage of ${\beta}C1$ transgenic N. benthamiana plants. In summary, this study revealed the pathogenicity of TYLCCNV in photosynthesis and disclosed the effect of ${\beta}C1$ in exacerbating the damage in photosynthesis efficiency by TYLCCNV infection.