• The Korean Journal of Mycology
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• v.39 no.1
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• pp.11-15
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• 2011

To provide basic information for Verticillium spp., molecular methods were applied to analyze genetic characteristics within Verticillium spp. including Verticillium dahliae, isolated from diseased plants in two regions of Korea. Five Korean isolates of V. dahliae causing Verticillium wilt on chrysanthemum were analyzed, together with six other Verticillium spp., using mitochondrial small subunit rRNA gene (rns) sequence and random-amplified polymorphic DNA (RAPD). In a phylogenetic tree based on rns region sequences, Korean V. dahliae isolates formed a single clade with foreign isolates, whereas the other Verticillium spp. formed separate groups. In addition to rns sequence analysis, a dendrogram based on RAPD fragment patterns also showed clustering of all V. dahliae isolates into one group, separate from the six different Verticillium spp., and the V. dahliae isolates formed three subgroups which corresponded to the regions of origin, Kumi, Busan city and Canada. This indicates that high genetic variation exists between regions, although the fungus was isolated from the same host plant, chrysanthemum. These results provide the foundation for the study of genetic diversity and relationships among V. dahliae isolates in Korea.

• Mycobiology
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• v.46 no.3
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• pp.254-259
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• 2018

Okra (Abelmoschus esculentus (L.) Moench) has gained more popularity as an economically significant plant for its nutritional and medicinal value, especially in China. During 2014-2016, the root disease of okra was discovered in four okra commercial fields surveyed in China. A fungul was isolated from the infected tissues, and was identified by Verticillium dahliae based on morphological characteristics. Pathogenicity test demonstrated that the fungus was pathogenic on okra, and fulfilled Koch's postulates. The analysis of three sequences revealed 99-100% identity with the reported V. dahliae strain in GenBank. Neighbor-joining analysis of the gene sequences revealed that the representative isolates were clustered with V. dahliae. To the best of our knowledge, this is the first report of Verticillium wilt of okra in China.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.437-441
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• 2019

Verticillium wilt disease is caused by a fungal plant pathogen Verticillium dahliae, which attacks commercial crops such as chrysanthemum. The conventional methods so far used to identify this fungal pathogen require high expertise and are time-consuming. Therefore, in this study, we developed an assay for the rapid and specific detection of V. dahliae infection using loop-mediated isothermal amplification (LAMP) method. For this assay, four primers for LAMP were designed for targeting cellulose-growth-specific protein partial mRNA gene in Verticillium dahliae. Under standard condition, the optimum reaction temperature for amplification is around 60 ℃ within 60 minutes. This LAMP assay was designed to amplify only present in V. dahliae. When this LAMP assay applied to the DNAs for four other soil-borne fungi and host plants, no amplification was detected. Therefore, this LAMP assay we developed for V. dahliae is expected to do detection at the early stage of its infection. The fast and reliable detection method will allow us to develop effective management system to monitor and control infection of this pathogen in chrysanthemum plant.

• The Plant Pathology Journal
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• v.17 no.4
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• pp.222-226
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• 2001

In 1997, 103 isolates of Verticillium were obtained from roots and stems of tomato plants showing wilt symptoms in greenhouses in eight areas of Korea. Out of these isolates, 75 were edintified as V. dahliae while 28 were identified as V. albo-atrum based on their morpho-logical and cultural characteristics. Both Verticillium species produced colonies with conidiophores, which were more or less erect, hyaline, with verticillate branches, and with 3-4 phialides at each node. V. dahliae produced microsclerotia, while V. albo-atrum produced resting dark mycelium. Optimum temperatures for mycelial growth of V. dahliae and V. albo-atrum on PDA were 22 and $26^{\circ}$, respectively. Mycelial growth of V. albo-atrum was slower than that of V. dahliae. Pathoge-nicity tests revealed that tomato cvs. Zuikoh No. 102, Kyoryokubeiju No. 2, Zuiken, Kagimuza, and Momotaro were susceptible to V. albo-atrum, while cvs. Zuikoh No. 102 and Kyoryokubeiju No.2 were susceptible to V. dahliae.

• BMB Reports
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• v.41 no.1
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• pp.79-85
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• 2008

The source of nitric oxide (NO) in plants is unclear and it has been reported NO can be produced by nitric oxide synthase (NOS) like enzymes and by nitrate reductase (NR). Here we used wild-type, Atnos1 mutant and nia1, nia2 NR-deficient mutant plants of Arabidopsis thaliana to investigate the potential source of NO production in response to Verticillium dahliae toxins (VD-toxins). The results revealed that NO production is much higher in wild-type and Atnos1 mutant than in nia1, nia2 NR-deficient mutants. The NR inhibitor had a significant effect on VD-toxins-induced NO production; whereas NOS inhibitor had a slight effect. NR activity was significantly implicated in NO production. The results indicated that as NO was induced in response to VD-toxins in Arabidopsis, the major source was the NR pathway. The production of NOS-system appeared to be secondary.

• Research in Plant Disease
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• v.13 no.1
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• pp.15-19
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• 2007

A wilt disease on the greenhouse-grown chrysanthemum occurred at Kumi, Masan and Busan, Korea in $2003{\sim}2005$. Symptoms of wilting, yellowing, and marginal burning started from lower leaves and progressed upward. Early symptoms often appeared on one side, involving only one part of the plant or one side of individual leaves or stems without a vascular discoloration. Vascular tissues of the infected leaf-base's discolored to brown. Fungal isolates obtained from discolored tissues were identified as Verticillium dahliae based on its cultural and morphological characteristics. The fungus showed whitish to creamy colony pattern with abundant dark brown to black elongated microsclerotia on PDA. Conidiophores were verticillately branched and conidia were ellipsoidal to sub-cylindrical shape, and measured as $2.5{\sim}8.8{\times}2.0{\sim}3.8{\mu}m$. Pathogenicity tests by root dipping resulted in similar symptoms observed in the naturally infected chrysanthemum in fields.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1149-1161
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• 2014

Cotton plants were sampled and ranked according to their resistance to Verticillium wilt. In total, 642 endophytic fungi isolates representing 27 genera were recovered from Gossypium hirsutum root, stem, and leaf tissues, but were not uniformly distributed. More endophytic fungi appeared in the leaf (391) compared with the root (140) and stem (111) sections. However, no significant difference in the abundance of isolated endophytes was found among resistant cotton varieties. Alternaria exhibited the highest colonization frequency (7.9%), followed by Acremonium (6.6%) and Penicillium (4.8%). Unlike tolerant varieties, resistant and susceptible ones had similar endophytic fungal population compositions. In three Verticillium-wilt-resistant cotton varieties, fungal endophytes from the genus Alternaria were most frequently isolated, followed by Gibberella and Penicillium. The maximum concentration of dominant endophytic fungi was observed in leaf tissues (0.1797). The evenness of stem tissue endophytic communities (0.702) was comparatively more uniform than the other two tissues. Eighty endophytic fungi selected from 27 genera were evaluated for their inhibition activity against highly virulent Verticillium dahliae isolate Vd080 in vitro. Thirty-nine isolates exhibited fungistasis against the pathogen at varying degrees. Seven species, having high growth inhibition rates (${\geq}75%$), exhibited strong antifungal activity against V. dahliae. The antifungal activity of both volatile and nonvolatile metabolites was also investigated. The nonvolatile substances produced by CEF-818 (Penicillium simplicissimum), CEF-325 (Fusarium solani), CEF-714 (Leptosphaeria sp.), and CEF-642 (Talaromyces flavus) completely inhibited V. dahliae growth. These findings deepen our understanding of cotton-endophyte interactions and provide a platform for screening G. hirsutum endophytes with biocontrol potential.

• The Plant Pathology Journal
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• v.16 no.3
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• pp.156-161
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• 2000

A wilt disease occurred on greenhouse-grown eggplants at Yeojoo, Korea in 1997. The wilted eggplants had leaves with gradual yellowing, interveinal necrosis, and marginal crinkling. Vascular tissues of diseased stems were discolored, turned black, and microsclerotia developed at the base of stems. The disease progressed from lower parts of the plants upward. Fungal isolates from discolored vascular tissues were initially whitish to cream color on potato-dextrose agar (PDA) plate, which later turned black due to the formation of microsclerotia. Conidiophores were erect, hyaline, verticillately branched, and had 3 or 4 phialides arising at each node. Phialides were hyaline, arranged in whorls, and measured as 17.5-32.5 x 2-3$\mu\textrm{m}$. Conidia were hyaline, ellipsoidal to sub-cylindrical, mainly one-celled, and measured as 5-8.8 x 2-4$\mu\textrm{m}$. Conidia were borne in small clusters at the tips of phialides. Microsclerotia formed on PDA plates, and consisted of globular cells that formed irregular masses of various shapes. Chlamydospores were absent. Based on these cultural and morphological characteristics, the fungus was identified as Verticillium dahliae Klebahn. Pathogenicity tests by root cutting, root dipping or soil drenching resulted in similar symptoms observed in the naturally infected eggplants. This is the first report on occurrence of Verticillium wilt of eggplant in Korea.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.192-204
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• 2024

In this study, the efficacy of the essential oil of Mentha longifolia, Achillea arabica and Artemisia absinthium plants were evaluated against important soil-borne fungal pathogens as Verticillium dahliae, Rhizoctonia solani, and Fusarium oxysporum. Essential oils were obtained from plants by hydrodistillation method and the chemical components of essential oils were determined by analyzing by gas chromatography-mass spectrometry. The main components found as piperitone oxide (13.61%), piperitenone oxide (15.55%), pulegone (12.47%), 1-menthone (5.75%), and camphor (5.75%) in M. longifolia, á-selinene 13.38%, camphor 13.34%, L-4-terpineneol 8.40%, (-)-á-Elemene 7.01%, 1,8-cineole 4.71%, and (-)-spathulenol 3.84% in A. arabica, and á-thujone (34.64%), 1,8-cineole (19.54%), pulegone (7.86%), camphene (5.31%), sabinene (4.86%), and germacrene-d (3.67%) in A. absinthium. The antifungal activities of the oils were investigated 0.05, 0.1, 0.25, 0.5, 1.00, and 2.00 μl/ml concentrations with the contact effect method. M. longifolia oil (1.00 and 2.00 μl/ml) has displayed remarkable antifungal effect and provided 100% inhibition on mycelial growth of V. dahliae, R. solani and F. oxysporum. The results obtained from this study may contribute to the development of new alternative and safe methods against soil-borne fungal pathogens.

• The Korean Journal of Mycology
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• v.14 no.2
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• pp.179-183
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• 1986

This survey was conducted to identify the fungal pathogens on the imported seeds during two months from September to October in 1985. Twenty-four species of fungi were detected from six kinds of the imported seeds and the following eight species of fungi have not been reported before in Korea.