Morphology, Molecular Phylogeny, and Pathogenicity of <i>Neofusicoccum parvum</i>, Associated with Leaf Spot Disease of a New Host, the Japanese Bay Tree (<i>Machilus thunbergii</i>)
During a survey of diseased plants on Wando Island, Korea from May to June 2020, a severe leaf spot disease was observed in the upper leaves of Japanese bay tree (<i>Machilus thunbergii</i>). Early symptoms were light blackish spots on the leaf surface and enlargement of older spots. Dry...
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MDPI AG
2021-04-01
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| author | Sungyu Choi Narayan Chandra Paul Kye-Han Lee Hyun-Jun Kim Hyunkyu Sang |
| author_facet | Sungyu Choi Narayan Chandra Paul Kye-Han Lee Hyun-Jun Kim Hyunkyu Sang |
| author_sort | Sungyu Choi |
| collection | DOAJ |
| description | During a survey of diseased plants on Wando Island, Korea from May to June 2020, a severe leaf spot disease was observed in the upper leaves of Japanese bay tree (<i>Machilus thunbergii</i>). Early symptoms were light blackish spots on the leaf surface and enlargement of older spots. Dry leaf spots surrounded with deep black margins were common throughout the plants. Symptomatic leaf samples were collected, and the causal pathogen was isolated on potato dextrose agar (PDA). Three fungal isolates (CMML20-1, CMML20-3, and CMML20-4) were cultured on PDA for morphological characterization at 25 °C in the darkness. Fungal colonies were circular, fast-growing, olivaceous to dark grey, and with abundant aerial mycelium. Sporulation was induced in 14 h-10 h light-dark conditions, and the conidia were single-celled, thin-walled with a smooth surface, ellipsoid with round apices, and measuring 17.5–20.5 (avg. 17.5) μm × 7.5–10.0 (7.9) μm. The morphological characteristics resembled those typical for <i>Neofusicoccum parvum</i>. Molecular identification was confirmed by partially sequencing the internal transcribed spacer (ITS) region and the translation elongation factor 1-α (EF1-α) genes. Pathogenicity tests were conducted on detached leaves and whole plants of <i>M. thunbergii</i>. High disease prevalence was observed, and Koch postulates were fulfilled. This is the first worldwide report of <i>N. parvum</i> causing leaf spots on <i>Machilus thunbergii</i>. |
| first_indexed | 2024-03-10T12:35:38Z |
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| id | doaj.art-4cbb3b355aad4576991b2ca1f98ef6b3 |
| institution | Directory Open Access Journal |
| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-10T12:35:38Z |
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| series | Forests |
| spelling | doaj.art-4cbb3b355aad4576991b2ca1f98ef6b32023-11-21T14:18:51ZengMDPI AGForests1999-49072021-04-0112444010.3390/f12040440Morphology, Molecular Phylogeny, and Pathogenicity of <i>Neofusicoccum parvum</i>, Associated with Leaf Spot Disease of a New Host, the Japanese Bay Tree (<i>Machilus thunbergii</i>)Sungyu Choi0Narayan Chandra Paul1Kye-Han Lee2Hyun-Jun Kim3Hyunkyu Sang4Department of Integrative Food Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, KoreaDepartment of Integrative Food Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, KoreaDepartment of Forest Resources, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, KoreaDepartment of Forest Resources, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, KoreaDepartment of Integrative Food Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, KoreaDuring a survey of diseased plants on Wando Island, Korea from May to June 2020, a severe leaf spot disease was observed in the upper leaves of Japanese bay tree (<i>Machilus thunbergii</i>). Early symptoms were light blackish spots on the leaf surface and enlargement of older spots. Dry leaf spots surrounded with deep black margins were common throughout the plants. Symptomatic leaf samples were collected, and the causal pathogen was isolated on potato dextrose agar (PDA). Three fungal isolates (CMML20-1, CMML20-3, and CMML20-4) were cultured on PDA for morphological characterization at 25 °C in the darkness. Fungal colonies were circular, fast-growing, olivaceous to dark grey, and with abundant aerial mycelium. Sporulation was induced in 14 h-10 h light-dark conditions, and the conidia were single-celled, thin-walled with a smooth surface, ellipsoid with round apices, and measuring 17.5–20.5 (avg. 17.5) μm × 7.5–10.0 (7.9) μm. The morphological characteristics resembled those typical for <i>Neofusicoccum parvum</i>. Molecular identification was confirmed by partially sequencing the internal transcribed spacer (ITS) region and the translation elongation factor 1-α (EF1-α) genes. Pathogenicity tests were conducted on detached leaves and whole plants of <i>M. thunbergii</i>. High disease prevalence was observed, and Koch postulates were fulfilled. This is the first worldwide report of <i>N. parvum</i> causing leaf spots on <i>Machilus thunbergii</i>.https://www.mdpi.com/1999-4907/12/4/440<i>Machilus thunbergii</i><i>Neofusicoccum parvum</i>new hostphylogenyKorea |
| spellingShingle | Sungyu Choi Narayan Chandra Paul Kye-Han Lee Hyun-Jun Kim Hyunkyu Sang Morphology, Molecular Phylogeny, and Pathogenicity of <i>Neofusicoccum parvum</i>, Associated with Leaf Spot Disease of a New Host, the Japanese Bay Tree (<i>Machilus thunbergii</i>) Forests <i>Machilus thunbergii</i> <i>Neofusicoccum parvum</i> new host phylogeny Korea |
| title | Morphology, Molecular Phylogeny, and Pathogenicity of <i>Neofusicoccum parvum</i>, Associated with Leaf Spot Disease of a New Host, the Japanese Bay Tree (<i>Machilus thunbergii</i>) |
| title_full | Morphology, Molecular Phylogeny, and Pathogenicity of <i>Neofusicoccum parvum</i>, Associated with Leaf Spot Disease of a New Host, the Japanese Bay Tree (<i>Machilus thunbergii</i>) |
| title_fullStr | Morphology, Molecular Phylogeny, and Pathogenicity of <i>Neofusicoccum parvum</i>, Associated with Leaf Spot Disease of a New Host, the Japanese Bay Tree (<i>Machilus thunbergii</i>) |
| title_full_unstemmed | Morphology, Molecular Phylogeny, and Pathogenicity of <i>Neofusicoccum parvum</i>, Associated with Leaf Spot Disease of a New Host, the Japanese Bay Tree (<i>Machilus thunbergii</i>) |
| title_short | Morphology, Molecular Phylogeny, and Pathogenicity of <i>Neofusicoccum parvum</i>, Associated with Leaf Spot Disease of a New Host, the Japanese Bay Tree (<i>Machilus thunbergii</i>) |
| title_sort | morphology molecular phylogeny and pathogenicity of i neofusicoccum parvum i associated with leaf spot disease of a new host the japanese bay tree i machilus thunbergii i |
| topic | <i>Machilus thunbergii</i> <i>Neofusicoccum parvum</i> new host phylogeny Korea |
| url | https://www.mdpi.com/1999-4907/12/4/440 |
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