• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.165-172
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• 1995

벼 잎집무늬마름병균(Rhizoctonia solani)의 균핵에서 분리한 길항세균 SJ-2를 대치 배양 방법에 의해 벼도열병균(Pyricularia oryzae)외 6종의 식물 병원균에 대한 억제 효과를 조사하였다. 형태 및 생리적 특성을 조사한 결과, 이 균은 Bacillus subtilis로 동정되었다. 이 균은 AM 1(antibiotic medium 1)액체 배지에서 항균 물질을 분비하였으며, 배양 2일째 가장 항균 활성이 높았다. Butyl alcohol로 배양액에서 항균 물질을 조추출하여 100$\mu\textrm{g}$/ml의 농도로 조제한 감자 한천 배지에서 P. oryzae의 15개균에 대한 생육을 조사한 결과 P. oryzae, R. solani, Cochliobolus sativus에 대해서는 100% 생장을 억제하였으며, C. miyabeanus, Alternaria alternata, Botrytis cinerea, Cladosporium fulvum, Colletotrichum gloeosporioides, Fusarium moniliforme, F. oxysporum에는 80% 이상의 억제 효과를 보인 반면 난균강에 속하는 병원균에 대한 효과는 낮게 나타났다. 활성물질을 분리 정제하여 동정한 결과 B. subtilis가 분비하는 항균 물질로 알려진 polypeptides계의 iturins로 밝혀졌다. 이러한 항균 물질은 벼 도열병균(P. oryzae)의 포자 발아 및 발아관의 팽대(swelling)를 야기했으며, 벼 잎집무늬마름병균(R. solani)에는 균사의 용균(lysis)현상을 일으켰다.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.447-450
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• 1997

Eighteen N-substituted phenyl 1, 3, 5-trimethylpyrazole-4-carboxamides were synthesized to screen for their mycelial growth inhibition activity against Rhizoctonia solani $K{\ddot{u}}hn$ $(pEC_{50})$ and to measure enzymatic inhibition activity of these compounds $(pI_{50})$ against succinate dehydrogenase (SDH) isolated from Rhizoctonia solani $K{\ddot{u}}hn$ A structure-activity relationship formulated by regression analysis showed that 79% of the variance in mycelial growth inhibition activity can be explained with SDH inhibition activity and chromatographic capacity factor $(\acute{k})$ as a hydrophobic parameter related to the penetration and transport processes in the biological system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.55-60
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• 1987

Fifty eight isolates of R. solani collected from rice plants infected to sheath blight disease at seven different locations through the country were evaluated for their cultural characteristics on media. Degree of resistance of nine rice varieties were tested by the seven isolates representing each culture type from the grouped pathogene-city. Great variation of cultural characterisics on PSA media was observed among isolates, and 58 isolates tested were grouped into 7 culture types. Locational distribution of isolates belong to each culture type was different between types, and only isolate type 'Ia' was distributed in all locations collected. The degree of pathogene-city of each isolate to rice adult plant was different between 7 culture types grouped, and no isolates infected severely on all tester rice varieties. The degree of resistance to the disease showed great variation among 9 tester varieties, and varietal reaction to the disease was varied along with isolates inoculated. An isolate, la, shown strong pathogenecity and distributed through 7 locations was selected for the screening of varietal resistance to rice sheath blight disease.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.64-69
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• 1998

New thirty derivatives of 5,6-dihydro-2-trifluoromethyl-1,4-oxathiin carboxanilide as substrate(S) were synthesized and their fungicidal activities in vivo against rice sheath blight(Rhizoctonia solani) and wheat leaf rust(Puccinia recondita) were examined. The structure activity relationships(SAR) between the activities($pI_{50}$) and a physicochemical parameters of substituents(X) at the phenylcarbamoyl group were analyzed using the adaptive regression analysis method. The 3-methoxy, 11, 3-isopropyloxy, 13 and 3-isopropyl substituent, 25 as X on the phenylcarbamoyl group exhibited the most highest fungicidal activity against the two fungi. The fungicidal potency of the (S) against Puccinia recondita was higher than Rhizoctonia solani. In case of Rhizoctonia solani, the molecular hydrophobicity(${\pi}>0$) and resonance effect(R<0) by meta-alkyl substitutents with electron donating were important factors in determining fungicidal activity. And the HOMO energy(HOMO>0), ABSQ, sum of absolute values of the atomic charges on each atom and specific polarizability(Sp.Pol<0) of (S) were significantly influential towards fungicidal activity against Puccinia recondita.. The interaction between (S) and receptor agonist from the based on SAR studies proceeds through charge-control reaction, and conditions to show higher activity has been also discussed.

• The Korean Journal of Pesticide Science
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• v.10 no.3
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• pp.157-164
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• 2006

Three dimensional quantitative structure-activity relationships (3D-QSARs) for the fungicidal activities against Rhizoctonia solani (RS) and Phytophthora capsici (PC) by N-phenyl substituents(X) of N-phenylthionocarbamate derivatives were studied quantitatively using comparative molecular field analysis (CoMFA) methodology based on different alignment approaches. Statistical quality of CoMFA models with field fit alignment were slightly higher than that of atom based fit alignment. The optimized CoMFA models (RS: RF2 & PC: PF2) were derived from field fit alignment and combination of CoMFA fields. And the statistical results of the two models showed the best predictability of the fungicidal activities based on the cross-validated value $q^2$ ($r^2_{cv.}$ =RS: 0.557 & PC: 0.676) and non-cross-validated value ($r^2_{ncv.}$ =RS: 0.954 & PC: 0.968), respectively. The selective fungicidal activities between two fungi were dependence upon the electrostatic field of substrate molecule. Therefore, the fungicidal activities from CoMFA contour maps showed that the fungicidal activity will be able to increased according to the modification of X-substituents on the substrate molecules.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.376-382
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• 2013

Rice sheath blight (ShB), caused by Rhizoctonia solani K$\ddot{u}$hn, is one of the serious fungal disease resulting in severe yield loss in rice field worldwide. There are limited sources of genetic resistance and no commercial cultivar with high level of ShB resistance is currently available in Korea. In order to seek available resources with high level of resistance to ShB, 40 rice germplasms were used to evaluate disease reactions including ShB, leaf blast and bacterial leaf blight and these germplasms also examined agronomic traits such as days to heading, culm length, panicle length, No. of panicles, No. of spikelets per panicle and so on. There is wide variation in agronomic characters and disease reactions. Rice germplasms also showed considerably different ShB reaction caused by inoculation at seedling stage. Areumbyeo, Gayabyeo, IR579-Es44 and IR64 showed more strong reaction to ShB than the others. Especially, Gayabyeo is considerably available to develop a new variety with resistance to ShB in Korea.

• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.158-164
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• 1995

토마토의 엽권에서 분리한 Fusariym graminearum이 분비하는 물질은 벼 도열병균(Pyricularia oryzae)의 여러 종의 식물병원 진균에 대한 항균활성을 나타내었으며, 이러한 활성물질을 PDA에서 본 균을 배양 한 후 chloroform으로 추출하여 분리정제 하였다. HPLC에 의하여 5종류의 활성 물질을 분획하였으며, 그중 1번(F402) 화합물을 벼 도열병균(P. oryzae)을 포함한 22개 식물 병원 진균에 대하여 살균 활성범위를 조사한 결과, 이 화합물은 50$\mu\textrm{g}$/ml 농도에서 Pythium ultimum, Rhizoctonia solani, Sclerotinia sclerotiorum은 전혀 억제하지 못하였으며, Phytophthora spp., Cladosporium fulvum, Fusarium spp., Corynespora cassicola에는 어느 정도의 활성이 있었지만 낮게 나타났고, P. oryzae, Cochliobolus miyabeanus, Alternaria solani는 100% 억제하여 활성이 높게 나타났다. 또한 장내 세균에 대한 활성을 MIC로 비교할 때 Streptococcus pyogenes, Streptococcus faecium에 대하여는 각각 12.5, 25 $\mu\textrm{g}$/ml였고 Staphylococcus aureus는 25-50$\mu\textrm{g}$/ml으로 나타났으며, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella aerogenes, Enterobacter cloacae에서는 100$\mu\textrm{g}$/ml 이상으로 활성이 나타나지 않았다. F402를 200$\mu\textrm{g}$/ml의 농도로 직접 살포한 식물체에서의 방제효과는 벼도열병, 벼 깨씨무늬병, 보리 흰 가루병에 대하여는 80%이상이었으나, 벼 잎집무늬마름병, 오이 잿빛곰팡이병, 토마토 역병, 밀 녹병에서는 낮았다.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.187-191
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• 2007

Comparative molecular similarity indice analysis (CoMSIA) models on the fungicidal activities of N-phenyl substituents (X) in N-phenyl-O-phenylthionocarbamate derivatives against rice sheath blight (Rhizoctonia solani: RS) and phytophthora blight (Phytophthora capsici: PC) were derived. Also, the characterizations of H-bonds between substrates and ${\beta}-tubulin$ were discussed quantitatively. It was revealed that, from the contour maps of CoMSIA models, the H-bond acceptor field contributed the most highly to fungicidal activity for two fungi in common. It is predicted that the selectivity in the fungicidal activity between two fungi is caused by results from the roles of H-bond donor disfavor functional groups in RS and H-bond acceptor disfavor functional groups in PC when these two groups induced at meta- and para-position on the N-phenyl ring. And also, if the substituents (X) are steric disfavor group, negative charge favor groups are introduced at the metaposition in RS and H-bond acceptor group is introduced at the para-position in PC, the antifungal activity against two fungi will be likely able to be increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4854-4862
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• 2010

Twenty five compounds isopropylmethylphenyl benzenesulfonate derivatives of thymol (1), 4-isopropyl-3-methylphenol (2), 5-isopropyl-3-methylphenol (3), 4-isopropylphenol (4), and 2-isopropylphenol (5) derivatives were synthesized. These compounds were analyzed for their structural confirmation with IR, GC/MS, and $^1H$-NMR. Synthetic compounds were tested against phytopathogenic fungi activities such as Pyrcularia grisea, Rhizoctonia solani, Phytophthora infestans, Colletotrichum orbiculare, and Sphaerotheca fusca. 2-Isopropyl-5-methylphenyl o-toluenesulfonate (1a), 2-isopropylphenyl 2,4,5-trichloro-benzenesulfonate (5b) and 2-isopropylphenyl 2-methyl-5-nitrobenzenesulfonate (5e) showed a potent in vivo antifungal activity against Pyrcularia grisea, Phytophthora infestans and Sphaerotheca fusca.

• Korean Journal Plant Pathology
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• v.1 no.1
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• pp.44-50
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• 1985

Effect of nitrogen sources on mycelial growth and sclerotial formation of Rhizoctonia solani causing rice sheath blight was studied by using sixty isolates from diseased samples of different localities in Chungbuk area. Based on the cultural characters, pathogenicity and sclerotial formation, three isolates of the fungus were selected. The virulence of the three isolates varied based on the percent of seeds germination, seedling blights and length and lesion number of lesions. As nitrogen sources, arginine, alanine, urea, ammonium sulfate and sodium nitrate were more effective for mycelial growth and sclerotial formation, than were cystine, methionine, lysine, histidine, tryptophan and thyrosine. The mycelium of R. so/ani grew well in a lower concentration of urea, sodium nitrate, arginine, ammonium sulfate and lysine, but in a higher concentration of proline, histidine, and alanine. In all nitrogen sources tested, high concentration of nitrogen nutrients greatly stimulated sclerotial formation of the fungus. Arginine, urea, and ammonium sulfate increased virulence of the fungus. All the isolates grown on the basic medium plus proline produced large sclerotia. Mycelial growth of the fungus was not well in the tryptophan-added medium, showing brown discoloration of medium.