• The Plant Pathology Journal
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• v.39 no.4
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• pp.409-416
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• 2023

Bacterial leaf blight of carrots caused by Xanthomonas hortorum pv. carotae (Xhc) is an important worldwide seed-borne disease. In 2012 and 2013, symptoms similar to bacterial leaf blight were found in carrot farms in Jeju Island, Korea. The phenotypic characteristics of the Korean isolation strains were similar to the type strain of Xhc. Pathogenicity showed symptoms on the 14th day after inoculation on carrot plants. Identification by genetic method was multi-position sequencing of the isolated strain JJ2001 was performed using four genes (danK, gyrB, fyuA, and rpoD). The isolated strain was confirmed to be most similar to Xhc M081. Furthermore, in order to analyze the genetic characteristics of the isolated strain, whole genome analysis was performed through the next-generation sequencing method. The draft genome size of JJ2001 is 5,443,372 bp, which contains 63.57% of G + C and has 4,547 open reading frames. Specifically, the classification of pathovar can be confirmed to be similar to that of the host lineage. Plant pathogenic factors and determinants of the majority of the secretion system are conserved in strain JJ2001. This genetic information enables detailed comparative analysis in the pathovar stage of pathogenic bacteria. Furthermore, these findings provide basic data for the distribution and diagnosis of Xanthomonas hortorum pv. carotae, a major plant pathogen that infects carrots in Korea.

• Korean journal of applied entomology
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• v.15 no.4 s.29
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• pp.199-204
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• 1976

Canna nosaic X bodies, which do not exist in tissues of the healthy plant and are originating in cells of virus infected Canna (Canna generalis BAILEY) with mosaic symptom, are easily observed under microscope through application of vital staining for 2-3 minutes with $1\%$ eosin of $H_2O$ solution added with slight amount of $CH_3COOH$ and distinguishing with N/5HCl followed by washing to inspect. The result of this experiment is summarized as following: 1) The X bodies are observed not only in epiermal cells of leaf of the mosaic virus infected Canna but in those of leaf sheath, stem, and root also, and it is expected that the X bodies are to exist in the flower cells of the disease infected Canna which were missed in this experiment. 2) Shape and nature of X bodies are not constant; in early stage of the disease development, the X bodies have equal contents and vague contour with their small size and round shape, but along with progress of the disease development they attain granular contents and clear contour with their increasing sige and defining shape in cytoplasm. In case of same individual pant, fully developed X. bodies. are increasing in cytoplasm in propoition to severity of mosaic and nettling of the diseased leaf. 3) The staining character of X bodies to eosin is more dense than that of nuclei; Xbodies are stained light red or red while nuclei are stained yellowish brown or light red. 1) It is assumed to be a result of cytoplasmic concentration around nucleus that X bodies are usunlly developed adjacent to nucleus and they are considered to be a cytoplasmic prodct. 5) Thus, I confirm that X bodies originsting in canna plant cells infected with mosaic virus aye multipling in the alive cells.

• Research in Plant Disease
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• v.22 no.1
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• pp.9-17
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• 2016

Nationwide survey for angular leaf spot (ALS) of strawberry caused by Xanthomonas fragariae, a quarantine disease in Korea, was performed in November 2012. In the survey, ALS was observed in eighty eight farmers' fields of Sukok, Jinju and Okjong, Hadong in Gyeongnam Province, and one field in Namwon of Jeollabuk Province. The infected field of Namwon closed immediately after the disease diagnosed ALS. In detailed survey of Sukok and Okjong areas during February 2012 to January 2015, ALS occurrence decreased from 45% farmer's fields on December 2012 to 5% on January 2015, and from 38% on November 2013 to 5% on January 2015, respectively. Phenotypic characteristics of the Korean strains were similar to those of the type strain of X. fragariae. A multilocus sequence analysis of Korean strains of X. fragariae was conducted using four genes; dnaK, fyuA, gyrB, and rpoD. All the Korean strains had the same sequences of the four genes. The concatenated sequences of the Korean strains shared 100% with that of the type strain of X. fragariae. All strawberry cultivars tested were susceptible to the strains of X. fragariae two weeks after inoculation. The inoculated sites were necrosis and expanded, which were rated 4 based on evaluation of inoculation site.

• Research in Plant Disease
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• v.20 no.2
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• pp.71-78
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• 2014

Gamma irradiation and its convergence with nano-silver particles and sodium dichloroisocyanurate (NaDCC) were investigated to inhibit germination and mycelial growth of Botrytis elliptica, the pathogen of lily leaf blight. In addition, the same treatments were studied on the process of disease development with detached leaf of lily cv. Siberia. Spray inoculation, which is closer to natural infection than wound inoculation, can be a way to investigate infection ability of the treated pathogen. The irradiating dose required to reduce the population by 90%, $D_{10}$, was 526 Gy irradiating with 0-2000 Gy gamma ray on the conidial suspension as well as the growing mycelia. Even at 2000 Gy, the mycelium was not killed but just delayed its growth at 1-2 days behind. Convergent treatment with 40 mg/l of NaDCC just before 200 Gy gamma irradiation was the best way to decrease the conidial germination about 1/1000 times. The control values of gamma irradiation were 23% and 19.5% at wound inoculation and spray inoculation, respectively. On wound-inoculation, the control value of NaDCC only was 89%, and that of NaDCC convergent with 200 Gy gamma irradiation was 32%. On sprayinoculation, the highest control value was NaDCC at 50%, and that of NaDCC convergent with gamma irradiation was 24%.

• Research in Plant Disease
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• v.24 no.1
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• pp.59-65
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• 2018

Pyraclostrobin is a broad-spectrum fungicide that inhibits mitochondrial respiration. However, it may also induce systemic resistance effective against bacterial and viral diseases. In this study, we evaluated whether pyraclostrobin enhanced resistance against the bacterial spot pathogen, Xanthomonas euvesicatora on pepper (Capsicum annuum). Although pyraclostrobin alone did not suppressed the in vitro growth of X. euvesicatoria, disease severity in pepper was significantly lower by 69% after treatments with pyraclostrobin alone. A combination of pyraclostrobin with streptomycin reduced disease by over 90% that of the control plants. The preventive control of the pyraclostrobin against bacterial spot was required application 1-3 days before pathogen inoculation. Our findings suggest that the fungicide pyraclostrobin can be used with a chemical pesticide to control bacterial leaf spot diseases in pepper.

• Journal of Plant Biology
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• v.3 no.2
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• pp.29-34
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• 1960

From the view point of phytopathological anatomy, the author has tried to study the effect of the shoot cluster disease virus on the internal structure of vascular tissues of chinese date tree (Ziziphus jujuba var. inermis Rehd.) comparing healthy checks and diseased plants. The materials were collected at the several sites, Kumgock-Ri, Masuc-Ri, Kyungi-Do, and near the campus of Korea University and around the area of Chongam-Dong, Seoul City, from August 15th to September 5th 1959. The leaf materials of healthy and diseased plants are fixed and aspirated in two kinds of killing solutions, formalin-acetic acid alcohol solution and Craf III solution. Sections were cut at 5-10$\mu$ thickness and stained with the double staining reagents of safranin and fast green. In this experiment the author has observed that there are marked structural changes in the infected plants in contrast of healthy checks. As figures 3-7 show that the following characteric changes have taken place on infected plants: 1) the arrangement of irregularly developed sieve elements in phloem, 2) the degeneration of phloem elements, 3) the irregular arrangement of epidermis in mid-vein, 4) more necrosis is observed among the parenchymatous cells, 5) abundant accumulatin of starch grains in parenchymatous cells, . In contrast to the above irregularities caused by the virus disease, the healthy checks appear normal structures as shown in figures 1 and 2. In adding to the all features noted above, the author could also observe an interesting feature that the xylem elements in mid-vein vascular bundle tissues are considerably disorganized to show the unspecialized vessel elements, the irregularly arranged xylem elements. However, this kind of irregularities which occur in xylem under the virus infection has not been reported previously. The features noted on the internal structure of vascular bundle under the condition of infection by the shoot cluster disease on chinese date trees appear to be more or less closely similar to the symptoms of the bunchy-top of banana and the yellow dwarf disease of barley in respect to the fact that whether phloem necrosis takes place as a primary symptom or a secondary symptom. In all these disease, primary histological changes of hypoplasia and hypertrophy are preceeded by the necrosis of phloem.

• The Plant Pathology Journal
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• v.21 no.2
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• pp.87-92
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• 2005

The structural differences between healthy and diseasedpanicle necks caused by Pyricularia oryzae were observed using electron-microscope. In the diseased panicle neck, the infection hyphae of the rice blast pathogen grew through the sclerenchymatous fiber tissue and reached to the central internal lacuna. Since the pathogen grew through the sclerenchymatous fiber tissues, the vascular bundle composed with xylem and phloem had been destroyed and finally the nutrients from the leaf and stem were not able to be transported into the grains. Infection of panicle base by the blast pathogen until 20 days after heading caused more than 50% of yield loss in both Jinmibyeo and Chucheongbyeo. There was a positive correlation between incidence of the panicle blast and rice yield losses. The regression equations between incidence of the panicle blast and yield losses were y= -3.61+496.7 ($R^2$=0.70) in Jinmibyeoand y=-3.93+520.2 ($R^2$=0.82) in Juanbyeo. The panicleblast caused deterioration of grain quality. Healthy grain rate was reduced by increase of panicle blast infection.

• Research in Plant Disease
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• v.10 no.1
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• pp.25-29
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• 2004

Over 98％ of Dendranthema x grandiflorum plants growing under a glasshouse in Gumi, Korea were infested with Meloidogyne hapla. Dendranthema x grandiflorum cv, 'Ardilo' had fewer eggmass (3.3/g root), followed by cv. 'Euro' (6.5), and cv. 'Monarisa' had the most eggmasses(17). The coefficient correlation between plant growth and nematode reproduction(number of eggmass per plant) indicated that nematode reduced chlorophyll content in leaf (r = -0.418, p = 0.059; r = -0.463, p = 0.040). Number of flowers, number of leaves and stem height to flower were positively correlated with flower weight(p < 0.05).

• The Korea Journal of Herbology
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• v.21 no.1
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• pp.57-62
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• 2006

Objectives : This study was carried out to investigate the inhibitive effects of cotton plant sectional extracts in cancer cell lines, Calu-6(human, Caucasian, lung, adenocarcinoma) and MCF-7(human, Caucasian, breast, adenocarcinoma). The incidence of cancer has been increasing even in korea due to the change of dietary life and westernization and becoming conspicuous as the disease threatening health. But cancer treatment have not been fully effective against the high incidence or low survival rate of most cancer. Methods : Calu-6 and MCF-7 cells were cultured and seeded in cell culture plates, respectively. And sectional extracts of cotton plant were treated to MCF-7 cells. Results and Conclusion : Sectional extracts of cotton plant showed no anti-proliferative effect on MCF-7 cells, but root and stem extracts showed strong anti-proliferative effects on Calu-6 cells. Fruit, leaf and flower extracts also showed anti-proliferative effects on Calu-6 cells but not so much like root and stem extracts. But seed extract showed no anti-proliferative effect on Calu-6 cells.

• Mycobiology
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• v.50 no.1
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• pp.12-19
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• 2022

Paramyrothecium eichhorniae sp. nov. was observed and collected from Chiang Mai and Phetchaburi Provinces, Thailand. This new species is introduced based on morphological and molecular evidence. This fungus is characterized by its production of sporodochium conidiomata with a white setose fringe surrounding an olivaceous green to dark green slimy mass of conidia, penicillately branched conidiophores, and aseptate and cylindrical to ellipsoid conidia. Phylogenetic analyses of combined LSU rDNA, ITS rDNA, tef1, rpb2, tub2 and cmdA sequence data using maximum parsimony, maximum likelihood and Bayesian approaches placed the fungus in a strongly supported clade with other Paramyrothecium species in Stachybotryaceae (Hypocreales, Sordariomycetes). The descriptions of the species are accompanied by illustrations of morphological features, and a discussion of the related taxa is presented.