• Title/Summary/Keyword: 벼잎집무늬마름병균(Rhizoctonia solani)

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Density and Viability of Sclerotia of Rice Sheath Blight Pathogen Overwintering in Field (벼잎집무늬마름병균(病菌) 월동균핵(越冬菌核)의 밀도(密度)와 활성(活性))

  • Kim, Choong-Hoe;Kim, Chang-Kyu
    • Korean journal of applied entomology
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    • v.26 no.2 s.71
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    • pp.99-106
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    • 1987
  • Three post-harvest fields each in four rice growing areas, Iri, Naju, Jinju and Taegu were randomly selected and surveyed during December 1986 to examine sclerotial density of Rhizoctonia solani overwintering in the field. Surface soil of $0.09m^2$ area was sampled in each field with three replications and sieved to collect sclerotia. Germiability and pathogenicity of collected sclerotia were examined in the laboratory. Number of sclerotia $({\times}10^6)/ha$ in Iri, Naju, Jinju, and Taegu was estimated from the sample as 2.7, 1.2, 0.7 and 0.6, respectively. Based on sample variance with simple random sampling in each area, number of sampling required for estimating average sclerotial density with the precision of 10% apart from a chance of 1 in 20 was calculated to 41, 132, 232, and 395 for Iri, Naju, Jinju and Taegu, respectively. Percentage of germination of sampled sclerotia on potato sucrose agar (PSA) ranged from 42 to 78% depending on the area, and averaged 60%. About 49% of the germinated sclerotia were pathogenic to a rice cultivar Jinheung that was used to test pathogenicity of the sclerotia. Proportion of viable sclerotia that have both germiability and pathogenicity was thus estimated to 0.29 of total sclerotia collected. R. solani cultures obtained from the sclerotia could be distinguished into three groups based on colony morphology on PSA. Size and number of sclerotia formed on PSA differed between group but were not associated with pathogenicity to Jinheung.

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Evaluation of Disease Resistance of a Leaffolder-resistant (Cry1Ac1) Rice Event and Gene Transfer to Plant Pathogens (혹명나방 저항성벼(Cry1Ac1)의 병해 저항성 및 병원균으로의 유전자 전이)

  • Nam, Hyo-Song;Shim, Hong-Sik;Yu, Sang-Mi;Lee, Se-Won;Kwon, Soon-Jong;Kim, Myung-Kon;Lee, Yong-Hoon
    • Research in Plant Disease
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    • v.15 no.3
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    • pp.202-208
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    • 2009
  • The genetically modified leaffolder-resistant (Cry1Ac1) rice plant was evaluated for the changes of resistance by comparing the occurrence of major diseases with a japonica type Korean rice variety, Nakdong which was the mother plant of the transgenic rice event, in greenhouse and field conditions. There was no difference in the occurrence of sheath blight and Helminthosporium blight between the two varieties in the fields. We couldn't find any difference of resistance for fungal blast and bacterial leaf blight by artificial inoculation in greenhouse. There was also no difference in the susceptibility to sheath blight in artificial inoculation tests confirming the results in the fields. The possibility of gene transfer of Bar and Cry1Ac1 from the genetically modified rice plant to naturally infected pathogens such as Fusarium moniliforme and Pyricularia oryzae in the field conditions was tested by PCR. And the possible transfer of those genes by continuous inoculation of Xanthomonas oryzae pv. oryzae and Rhizoctonia solani was also tested. However, we couldn't find any possibility of transfer of the genes in natural and artificial conditions.

Isolation and Optimal Culture Conditions of Brevibacillus sp. KMU-391 against Black Root Pathogens Caused by Didymella bryoniae (덩굴마름병원균인 Didymella bryoniae의 생물학적 방제를 위한 길항세균의 분리 및 특성)

  • Park Sung-Min;Jung Hyuck-Jun;Kim Hyun-Soo;Yu Tae-Shick
    • Korean Journal of Microbiology
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    • v.42 no.2
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    • pp.135-141
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    • 2006
  • We isolated a bacterium which produces antifungal substances from the Sanktpeterburg soils at Russia. The iso-lated strain was identified as Brevibacillus sp. and shown a strong antifungal activity on plant pathogenic fungi. Brevibacillus sp. KMU-391 produced maximum level of antifungal substances under incubation aerobically at $30^{\circ}C$ for 48 hours in trypticase soybean broth containing 1.0% sucrose and 1.0% polypeptone at 180 rpm and initiated pH adjusted to 7.0. Precipitate of culture broth by $30{\sim}60%$ ammonium sulfate precipitation exhibited strong antifungal activity against Didymella bryoniae by dry cell weight. Butanol extract of cultured broth also shown fungal growth inhibitory activity against Botrytis cinerea KACC 40573, Botrytis fabae KACC 40962, Colletotrichum gloeosporioides KACC 40804, Colletotrichum orbiculare KACC 40808, Didymella bryoniae KACC 40669, Fusarium graminearum KACC 41040, Fusarium oxysporum KACC 40037, Fusarium oxysporum KACC 40052, Fusarium oxysporum f, sp. radicis-Iycopersici KACC 40537, Fusarium oxysporum KACC 40902, Monosporascus cannonballus KACC 40940, Phytophthora camvibora KACC 40160, Rhizoctonia solani AG-1(IA) KACC 40101, Rhizoctonia solani AG-4 KACC 40142, and Scleotinia scleotiorum KACC 41065 by agar diffusion method.

In vitro and in vivo antifunal activaties of derivatives of thymol( I ) and carvacrol(II) againt phytopathogenic fungi (Thymol과 Carvacrol 유도체들의 합성과 식물병원균에 대한 항균활성)

  • Choi, Won-Sik;Jung, Chan-Jin;Jang, Do-Yun;Cha, Kyoung-Min;Um, Dae-Yong;Kim, Tae-Jun;Jung, Bong-Jin
    • The Korean Journal of Pesticide Science
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    • v.10 no.4
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    • pp.237-248
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    • 2006
  • Forty one compounds such as ester, sulfonyl ester, carbamate, ether and phosphoyl ester derivatives of thymol(I) and carvacrol(II) were synthesized. These derivatives were identified by IR, GC/MS and $^1H$-NMR spectra. Their antifungal activities were tested against various plant pathogenicfugi. Among them, several compounds were showed potent in vivo antifungal activities. The selected compounds showing in vitro antifungal activities were tested in vivo antifungal activities aganint 5 plant diseases such as rice blast, rice sheath blight, tomato late blight, cucumber anthracnose, and cucumber gray mold. As a result, 2-isopropyl-5-methylphenylacetate(I-1a) effectively suppressed the development cucumber gray mold and rice blast. Methyl(2-isopropyl-5-methylphenoxy)acetate(I-6d) and ethyl 4-(5-methyl-2-isopopylphenoxy)crotonate(I-7d) also showed potent in vivo antifungal actively againt rice sheath blight and tomato late blight, respectively.

A Synthesis of Alkylphenyl fluorobenzoate Derivatives and Their Antifungal Activities on Several Phytopathogens (Alkylphenyl fluorobenzoate 유도체들의 합성과 몇 가지 식물병원균에 대한 항균활성)

  • Choi, Won-Sik;Cha, Kyung-Min;Kim, Young-Sun;Jang, Soon-Ho;Lim, Sang-Ho;Choi, In-Young;Kim, Tae-Jun;Jung, Bong-Jin
    • The Korean Journal of Pesticide Science
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    • v.12 no.4
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    • pp.307-314
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    • 2008
  • Sixty compounds such as alkylphenyl fluorobenzoate esters from thymol(I), 5-isopropyl-3-methylphenol (II), 4-isopropyl-3-methylphenol (III), 2-sec-butylphenol (IV) and 4-sec-butylphenol (V) were synthesized. These derivatives were identified by IR, $^1H$-NMR spectrometer and GC/MS. Their in vivo antifungal activities were tested against phytopathogens such as Phytophthora infestans, Botrytis cinerea, Colletotrichum orbiculare and Rhizoctonia solani. As the result, 2-sec-butylphenyl 2,5-difluorobenzoate (IV-6) and 4-sec-butylphenyl 2,5-difluorobenzoate (V-6) showed 90% above antifungal activity against Botrytis cinerea. 2-Isopropyl-5-methylphenyl 2,3,6-trifluorobenzoate (I-11), 2-isopropyl-5-methylphenyl 2,4,5-trifluorobenzoate (I-12), 5-isopropyl-3-methylphenyl 2,3,6-trifluorobenzoate (II-11), 4-isopropyl-3-methylphenyl 2,3,6-trifluorobenzoate (III-11) and 4-isopropyl-3-methylphenyl 2,4,5-trifluorobenzoate (III -12) showed 90% above potent antifungal activity against Colletotrichum orbiculare.