• Title/Summary/Keyword: hyphal extension

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Antifungal activity of a chitinase purified from bean leaves (강낭콩 잎에서 정제한 키틴분해효소의 항균활성)

  • Park, Ro-Dong;Song, Kyong-Sook;Jung, Ihn-Woong
    • Applied Biological Chemistry
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    • v.35 no.3
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    • pp.191-195
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    • 1992
  • In order to elucidate the plant-microorganism relationship, we purified an ethylene-inducible, basic 30 KD endochitinase from bean leaves and studied its antifungal activity by a hyphal extension-inhibition assay. The purified chitinase was effective in the inhibition of hyphal growth of Aspergillus fumigatus, Botrytis cinerea, Fusarium oxysporum, Rhizoctonia solani, while microbial chitinases of Serratia marcescens and Streptomyces griceus, egg white lysozyme and papya protease didn't affect hyphal growth of the fungi. The chitinase degraded the cell walls of Micrococcus lysodeikticus, suggesting the lysozyme activity of the chitinase. We discussed the implication of the bifunctional chitinase/lysozyme activities of the protein with hydrolysis of chitin in the rapidly extending hyphae of the fungi.

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Chitosan이 사과 겹무늬썩음병균 Botryosphaeria dothidea의 생육에 미치는 영향

  • 이승지;엄재열;이용현
    • Microbiology and Biotechnology Letters
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    • v.24 no.3
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    • pp.261-267
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    • 1996
  • To examine the potential utilization of chitosan, the biodegradable natural polymer, as a control agent of apple white rot caused by Botryosphaeria dothidea in a new control measure by coating it on the diseased branches, the various antifungal activities of chitosan was investigated. Chitosan showed significant inhibitory effect on the mycelial growth of B. dothidea, along with the morphological changes including hyphal swelling and ultrastructural changes on solid PDA medium. In liquid PD broth medium, the chitosan showed more significant effect on the growth of B. dothidea also forming cell clusters indicating affection on the hyphal extension. The growth of B. dothidea was inhibited more than 90% at the concentration of 1.0 mg/ml. Chitosan also detained the spore germination and induced the morphological change of germ tubes. Glucosamine, monomer of chitosan, did not affect on the growth of B. dothidea indicating the antifungal activity was caused by chitosan polymer.

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Occurrence of Stem Rot of Astragalus sinicus Caused by Sclerotium rolfsii in Korea (Sclerotium rolfsii에 의한 자운영 흰비단병의 발생)

  • Kwon, Jin-Hyeuk;Lee, Heung-Su;Kim, Tae-Sung;Song, Won-Doo;Cho, Hyeoun-Suk
    • The Korean Journal of Mycology
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    • v.37 no.2
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    • pp.198-200
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    • 2009
  • From 2008 to 2009, the stem rot of Astragalus sinicus L. caused by Sclerotium rolfsii occurred sporadically in Gyeongnam area, Korea. The typical symptom is water-soaking, rotting and wilting on the stem. The infected plants were eventually died. White mycelial mats were spread over lesions, and then sclerotia were formed on stems and near soil line. The sclerotia were globoid in shape, white to brown in color, 1-3 mm in size and the hyphal width was 3-9 μm. The optimum temperature for mycelial growth and sclerotial formation on PDA was 30oC. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report on the stem rot of A. sinicus caused by S. rolfsii in Korea.

Stem Rot on Ligularia fischeri Caused by Sclerotium rolfsii in Korea (Sclerotium rolfsii에 의한 곰취 흰비단병)

  • Moon, Youn-Gi;Kim, Se-Won;Choi, Jun-Keun;Kwon, Soon-Bae;Shim, Hong-Sik;Ju, Ho-Jong;Choi, In-Young
    • Research in Plant Disease
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    • v.21 no.1
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    • pp.36-39
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    • 2015
  • In June 2012 and 2013, a destructive stem rot symptoms of Ligularia fischeri occurred sporadically in Hoengseong-gun and Pyeongchang-gun Gangwon-do, Korea. The typical symptom included water-soaking on the main stem, rotting, wilting and blighting, which eventually leads to death of the plant. White mycelial mats were spread over lesions and brown sclerotia were formed on stems and near soil surface. The sclerotia were white to brown, spherical or irregular, 1-3 mm in size on potato dextrose agar (PDA), The optimum temperature range of hyphal growth was $25-30^{\circ}C$ and the hyphal diameter was $4-10{\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. The resulting sequence of 695 bp was deposited in GenBank. A BLAST search revealed that sequences of the this isolates showed >99% identity with those of Sclerotium rolfsii. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers ITS rDNA, the fungi were identified as S. rolfsii. A pathogenicity test was carried out to fulfill Koch's postulates. To our knowledge, this is the first report of S. rolfsii on Ligularia fischeri in Korea.

Sclerotium Rot of Cowpea (Vigna sinensis King) Caused by Sclerotium rolfsii (Sclerotium rolfsii에 의한 동부 흰비단병)

  • Kwon, Jin-Hyeuk;Kang, Dong-Wan;Han, Inyoung;Choi, Yong-Jo;Lee, Sang-Dae;Son, Daeyoung
    • The Korean Journal of Mycology
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    • v.44 no.1
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    • pp.61-63
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    • 2016
  • Sclerotium rot disease on cowpea (Vigna sinensis King) was observed in the exhibition field of Gyeongsangnam-do Agricultural Research and Extension Services in September 2015. Lesions were covered by white mycelial mats, and numerous sclerotia were formed on the stem near the soil line. The sclerotia were globoid in shape, 1~3 mm in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation on potato dextrose agar (PDA) was $30^{\circ}C$, with the hyphal width of $4{\sim}8{\mu}m$. For molecular identification, the complete internal transcribed spacer (ITS) rDNA region of the causal fungus was sequenced and analyzed. Based on the mycological characteristics, ITS rDNA sequence analysis, and pathogenicity test, this fungus was identified as Sclerotium rolfsii. This is the first report of sclerotium rot on cowpea caused by S. rolfsii in Korea.

Occurrence of Sclerotium Rot of Corn Caused by Sclerotium rolfsii in Korea (Sclerotium rolfsii에 의한 옥수수 흰비단병 발생)

  • Kwon, Jin-Hyeuk;Kang, Dong-Wan;Lee, Heung-Su;Choi, Si-Lim;Lee, Sang-Dae;Cho, Hyeoun-Suk
    • The Korean Journal of Mycology
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    • v.41 no.3
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    • pp.197-199
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    • 2013
  • The sclerotium rot of corn (Zea mays L.) occurred sporadically at the experimental field of Gyeongsangnam-do Agricultural Research and Extension Services in July 2011. The infected stems were water-soaked, wilted, and finally led to the death of the whole plants. White mycelial mats were spread over lesions, and then sclerotia were formed on stem and near soil line. The sclerotia were globoid in shape, white to brown in color and 1-3 mm in size. The hyphal width was $4-8{\mu}m$. The optimum temperature for mycelial growth and sclerotia formation on PDA was 30 on PDA. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of sclerotium rot on corn caused by S. rolfsii in Korea.

Sclerotium Rot of Pulsatilla koreana Nakai Caused by Sclerotium rolfsii (Sclerotium rolfsii에 의한 할미꽃 흰비단병)

  • Kwon, Jin-Hyeuk;Hwang, Gap-Chun;Lee, Seol-Bi;Choi, Yong-Jo;Lee, Sang-Dae;Nguyen, Le-Minh
    • Research in Plant Disease
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    • v.21 no.4
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    • pp.334-336
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    • 2015
  • Sclerotium rot on Pulsatilla koreana was observed in the exhibition field of Jinju Agriculture Technology Center in July 2013. The infected plants showed water-soaked, blighted and rotted symptoms. White mycelial mats spread over lesions, and then numerous sclerotia were formed on flower stalk and flower stem near the soil line. The sclerotia were globoid in shape, 1-3 mm in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation on PDA was $30^{\circ}C$ and the hyphal width was $4-8{\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. For molecular identification, the complete ITS rDNA sequence of the causal fungus was sequenced and analyzed. On the basis of mycological characteristics, ITS rDNA sequence analysis, and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of sclerotium rot on Pulsatilla koreana caused by S. rolfsii in Korea.

Occurrence of Stem Rot of Sunflower (Helianthus annuus) Caused by Sclerotium rolfsii (Sclerotium rolfsii에 의한 해바라기 흰비단병 발생)

  • Kwon, Jin-Hyeuk
    • Research in Plant Disease
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    • v.16 no.3
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    • pp.323-325
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    • 2010
  • The stem rot of sunflower (Helianthus annuus) occurred sporadically in the experimental field of Gyeongsangnam-do Agricultural Research and Extension Services, on September, 2009. The infected plants were wilted and water-soaked brown spots were formed on the stem, than infected stems were mostly died. White mycelial mats were spread over lesions, and then sclerotia were formed on stem and near soil line. The sclerotia were globoid in shape, 1~3 mm in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation on PDA was $30^{\circ}C$ and the hyphal width was $4{\sim}8\;{\mu}m$. The typical clamp connections were observed in the hyphae of the pathogenic fungus. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii. This is the first report on the stem rot of sunflower by S. rolfsii in Korea.

Survey and Screening of Fungicide for the Control of Tomato Black Leaf Mold Pseudocercospora fuligena

  • Lee, Mun Haeng;Lee, Hee Keyung;Cho, Pyeng Hwa;Kim, Young Shik;Cho, Suk Keyung;Kim, Sung Eun;Chun, Hee;Kim, Hong Gi;Kim, Sang Woo;Lee, Youn Su
    • Research in Plant Disease
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    • v.21 no.2
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    • pp.94-98
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    • 2015
  • Tomato black leaf molds were collected from the six metropolitan cities, which were occurred mainly from the end of August until November. There was no significant difference on the fungal growth between potato dextrose agar and tomato-oatmeal agar media. The mycelial growth of the fungus was robust at a relatively high temperature, from 28 to $30^{\circ}C$. The suppression rates of hyphal growth ranged from 17-98% on the media supplemented with four different chemicals such as difenoconazole, fluquinconazole and prochloraz manganese complex, metconazole, and flutianil and there is no different suppression rates of the fungicides on the tested Pseudocercospora fuligena isolates.

Stem Rot of Perilla Caused by Sclerotium rolfsii in Korea (Sclerotium rolfsii에 의한 들깨 흰비단병)

  • Kwon, Jin-Hyeuk;Choi, Si-Lim;Lee, Heung-Su;Shim, Hong-Sik
    • The Korean Journal of Mycology
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    • v.40 no.3
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    • pp.177-178
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    • 2012
  • Stem rot of perilla (Perilla frutescens var. japonica Hara) occurred sporadically in the exhibition field at Gyeongsangnam-do Agricultural Research and Extension Services in Korea. The infected stems are water-soaked, rotted, wilted and finally leads to the death of the whole plants. The sclerotia, 1-3 mm, white to brown, spherical, were formed on lesions and the surface of soil line. The optimum temperature for mycelial growth and sclerotia formation was $30^{\circ}C$ on potato dextrose agar and the hyphal width was 4-9 ${\mu}m$. The typical clamp connections were observed in the hyphae of the fungus. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of stem rot on perilla caused by S. rolfsii in Korea.