• The Korean Journal of Soil Zoology
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• v.7 no.1_2
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• pp.45-49
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• 2002

Meloidogyne marylandi Jepson & Golden, 1987 is described from Zoysia grass collected in Cheonan, Korea. The nematode did not produce galls, and females were generally surrounded by a massive egg sac. Perineal patterns of female were a high to rounded arch with shoulders, wavy striae usually forming a rough. Vulva and anus were sunken. Second-stage juvenile body length was 390.3 $\mu\textrm{m}$ (290-430), tail length 55.1 $\mu\textrm{m}$ (49-59) and lateral field with 4 incisures. Male stylet length was 18.1 $\mu\textrm{m}$ (15-24), spicules length 26.2 $\mu\textrm{m}$ (23-29) and lateral field with 4-5 incisures.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.27-27
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• 2015

Clubroot (Plasmodiophora brassicae) is a serious agricultural problem affecting Brassica crop production worldwide. It also infects the model plant Arabidopsis thaliana. During infection, this biotrophic pathogen manipulates the development and metabolism of its host leading to the development of galls in the root and hypocotyl. In turn, its own development is strongly influenced by the host. The aim of this study is to investigate the metabolism of clubroot-infected plants using a combination of transcriptomic and metabolomic approaches. We have used direct injection mass spectrometry to obtain a metabolic fingerprint of when changes in the metabolome occur and linked this with changes in host and pathogen gene expression. We have identified alterations in carbohydrate metabolism that occur during P. brassicae infection of A. thaliana plants. Transcriptomic analysis showed that host genes associated with sugar transport and metabolism were induced during gall formation and that the pathogen also expresses genes associated with these processes. We have examined the impact of inactivating host sucrose synthase, cytosolic invertase and sugar permeases on gall formation, identifying host genes that are required for gall formation. We have also explored how sugar status is changed in root tissue, developing and mature leaf during infection of wild type and mutant plants.

• The Plant Pathology Journal
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• v.33 no.1
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• pp.66-74
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• 2017

This study was conducted to examine infectivity (penetration and gall and egg-mass formations) of the root-knot nematodes, Meloidogyne incognita and M. hapla, on carrots grown in soil conditions of 5 different soil textures consisting of bed-soil (b) and sand (s) mixtures (b-s mixtures) at the ratios of 10:0, 7:3, 5:5, 3:7, and 0:10. For M. incognita, the nematode penetration rates in b-s of 0:10 (100% sand) were significantly higher than in the other b-s mixtures, more greatly at 2 and 5 days after inoculation than at 10 DAI, while no significant differences in the penetration rates were mostly shown for M. hapla at the above DAI. However, for both nematodes, gall and egg-mass formations were remarkably increased in the b-s mixture of 0:10, compared to the other b-s mixtures, which is coincided with the general aspects of severe nematode infestations in sandy soils. This suggests the increased gall and egg-mass formations of M. incognita should be derived from the increased penetration rates in the sandy soil conditions, which provide a sufficient aeration due to coarse soil nature for the nematodes, leading to their mobility increased for the enhanced root penetration. For M. hapla, it is suggested that the sandy soil conditions affect positively on the healthy plant growth with little accumulation of the inhibitory materials and sufficient aeration, enhancing the nematode growth and feeding activities. All of these aspects provide information reliable for the development screening techniques efficient for the evaluation of the nematode resistance in the breeding programs.

• Applied Biological Chemistry
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• v.30 no.4
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• pp.293-299
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• 1987

Bradyrhizobium japonicum spheroplasts were prepared by culturing cells in the presence of glycine, follwed by treatment with lysozyme. The cells were examined by electron microscopy during the formation of spheroplast. Then Ti plasmid from Agrobacterium tumefaciens 15955 was introduced into Bradyrhizobium japonicum by glycine-lysozyme induced spheroplast transformation. After cell wall regeneration, transformants were selected by the ability of utilization of octopine. Transformation were received at a frequency of $1{\times}10^{-7}$. The transformants obtained from spheroplast transformation harbored the introduced Ti plasmid, which was identified by agarose gel electrophoresis. Furthermore, the differences in their gene products were observed between the transformant and the recipient cell by two-dimensional polyacrylamide gel electrophoresis. The transformants which still possessed the same ability nodulate soybean (Glycine max.) as that of the original host strain, acquired the ability to induce tumor on Petunia hybrida like Agrobacterium, but formed the small crown galls in size compared to those of Agrobacterium tumefaciens.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.401-408
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• 2016

The present study described the isolation of 2-methylbutyric acid (2-MBA) produced from Bacillus pumilus L1, to subsequently investigate its nematicidal activity for the control of the root-knot nematode. The results showed that 2-MBA could be purified by chromatographic techniques and was identified using nuclear magnetic resonance and liquid chromatography-mass spectrometry. Crude extract and partially purified compounds had a significant effect on the inhibition of egg hatchability and second-stage juvenile (J2) mortality. A dose-dependent effect of 2-MBA was observed for J2 mortality and egg hatchability. Egg hatchability was 69.2%, 59.9%, 32.7%, and 0.0% at 125, 250, 500, and $1000{\mu}g\;mL^{-1}$ of 2-MBA after 4 d of incubation, respectively. Meanwhile, J2 mortality was in the range of 24.4%-100.0% after 2 d of incubation, depending on the concentrations of 2-MBA used. A pot experiment also demonstrated that treatment of B. pumilus L1 culture caused a significant reduction in the number of galls, egg masses, and J2 population than that of the tap water (TW) control. However, as the B. pumilus L1 culture concentration was decreased, the efficacy of nematode control by treatment of B. pumilus L1 culture was reduced compared to that of TW. B. pumilus L1 inoculation at different concentrations also promoted cucumber plant growth. Therefore, our study demonstrated the potential of 2-MBA from B. pumilus L1 as a biocontrol agent against the root-knot nematode and a plant growth promoter for cucumber plants.

• Korean journal of applied entomology
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• v.56 no.1
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• pp.77-81
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• 2017

The results from our investigation showed differences in pine needle damage by Thecodiplosis japonensis Uchida et Inouye and indicate serious environmental pollution caused by a petrochemical industrial complex. The gall formation rate by T. japonensis near the industrial complex was 47.94% compared to 9.94% in the site farthest from the complex. The average length of pine needles damaged by T. japonensis near the industrial complex and farthest site were 4.5 cm and 4.9 cm, respectively. The average number of larvae in pine needle galls near the industrial complex and farthest site were 3.4 and 2.4, respectively. The average body length and width of fullgrown larvae near the industrial complex were 2.40 mm and 0.7 mm, respectively, whereas larvae in the site farthest from the complex were 2.45 mm in length and 0.71 mm in width.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.137-143
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• 2002

Grape phylloxera, Daktulosphaira vitifoliae(Fitch), is a destructive grape insect pest because it forms root galls and kills the plant by directly destroying root system. The effects of insecticide treatments were examined to establish the chemical control system of phylloxera, and the damage by this insect was investigated in grapevine yards. The treatments of 40kg carbofuran 3GR per ha and carbosulfan 20WP of 10$\ell$ (1,000$\times$) per tree successfully reduced phylloxera densities. After the insecticide treatments in early season, the phylloxera population rebuilt up again at harvest season. In a grapevine yard where two times of carbofuran treatment (mid-May and post-harvest treatment) were applied a year from 1998 to 2000, total yield per ha in 2000 showed an increase of 30% over that of 1998. But the yield in 2000 was low 20% compared to the average standard yield of Korean grapevine yards. In a grapevine yard without chemical treatment during the same years, total yield per ha in 2000 showed 53% reduction compared to that of 1998. Also, damaged vines by phylloxera abruptly increased from 3% in 1998 to 50% in 2000.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.339-346
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• 2006

Total 90 species of medicinal plants were surveyed to see if they have any suppressive effects on the dinsity of M hapla at the exhibition field in the Chinan medicinal herbs experiment station. In 70 species including Achyranthes japonica, root-knot and/or egg sac of M. hapla was not found and these plants were planted in C. lanceolata field to check the degree of M. hapla infection. In 26 species including A. japonica, M. hapla infection was not observed. Simultaneously, 30 species were planted in pots to find out degree of infection by M. hapla. Dianthus chinensis, Rudbeckia bicolor, Sedum kantschaticum, Ricinus communis, Anemarrhena asphodeloides, Malva verticillate, Chelidonium majus, Sesamum indicum, Agrimonia pilosa, Geum aleppicum, Sanguisorba officinalis and Scrophularia buergeriana were free from infection. While the number of galls and density of M. hapla in soil were higher to high innoculation density, and the growth of C. lanceolata was rower.

• Research in Plant Disease
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• v.12 no.3
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• pp.284-286
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• 2006

Leaf gall was occurred on Rhododendron indicum(L.) Sweet[=Azalea indica L.] in a farmer's garden located in Geumsan-myon, and along the walk way of Gangju pond in Jeongchon-myon, Jinju, Korea. The infected leaves was deformed into very conspicuous, pale, fleshy shapeless galls. Basidia were fusiform, $3{\sim}5$ sterigma, and $8{\sim}35{\times}3{\sim}6{\mu}m$ in size. Basidiospores were musiform, straight or curved and $10{\sim}22{\times}3{\sim}5{\mu}m$ in size. The causal organism was identified as Exobasidium japonicum Shirai based on the mycological characteristics of the fungus and pathogenicity. This is the first report on the leaf gall of R. indicum caused by E. japonicum in Korea.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.177-180
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• 2003

Pasteuria penetrans KW1 (PP), parasitic bacterium of nematode, was isolated from oriental melon greenhouse soil in Korea and evaluated for the suppression effect on the reproduction of southern root-knot nematode, Meloidogyne incognita (MI), in lettuce (Lactuca sativa L. var. Chungchima) and oriental melon (Cucumis melo L. var. Eunchun). Pot experiments were conducted by planting the lettuce seedlings in medium inoculated with 5,000 MI juveniles/pot (J), J +100,000 PP endospores/l g medium, and J +200,000 PP endospores/1 g medium. After 11 weeks of plantation, number of root galls in J +200,000 PP endospores/1 g medium was decreased to 92/root (38.9%, control effect), compared to the J of 150/root. In the second plantation of lettuce in the same pots, the numbers of root gall were significantly decreased in PP treated pots with 75 (77.2%, control effect) and 150/root (54.4%, control effect) in J +200,000 and J +100,000 PP endospores/1 g medium, respectively, compared to the J of 330/root when harvested at 10 weeks after planting. In oriental melon, root gall percentages were 32.1 (60.2%, control effect) and 52.9％ (34.5%, control effect) in J +200,000 and J + 1(10,000 endospores/l g medium which were significantly lower than that of 80.7％ in J.