• 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.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.183-190
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• 1981

Alternaria sesami, A. sesamicola, A. tenuis, A. longissima, Cercospora sesami, Cephalosporium sp., Corynespora cassiicola, Fusarium equiseti, F. moniliforme, F. oxysporum, F. semitectum, Macrophomina phaseolina and Myrothecium roridum were detected from 40 seed samples of sesame. A sesami, A. sesamicola, A. tenuis and C. cassiicola were the predominant fungi. Except C. cassiicola, all fungi were almost completly reduced and wiped out the infection by pretreatment with chlorine. Plating components also indicate that C. cassiicola was well-established infections. Seedborne infection of C. cussiicola caused heavy seed rot and seedling mortality. Detailed description has been given on the habit character of C. cassiicola under stereoscopic microscope and the variation in colony character and spore morphology have been taken into account. In inoculation experiments, C. cassiicola produced severe leaf and stem spots and blights on sesame plants resulted in ultimate death of the plants. A. sesami, A. sesamicola A. longissima and C. sesami also produced mild to severe leaf spotting and leaf blight when suspension of their conidia were sprayed on to plants. In soil inoculation experiments, F. oxysporum and M. phaseolina were the most pathogenic causing seed rot and seedling blight.

• The Korean Journal of Mycology
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• v.20 no.2
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• pp.109-117
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• 1992

Chemotactic responses of five motile saprophytic and one phytopathogenic bacteria e.g. Agrobacterium radiobacter, Bacillus subtilis, B. polymyxa, Pseudomonas aeruginosa, P. fluorescens and Xanthomonas malvacearum towards exudate of Cochliobolus sativus conidia, Fusarium of oxysporum f. sp. ciceri chlamydospores, Macrophomina phaseolina sclerotia and Phytophthora drechsleri f. sp. cajani oospores were determined in vitro at different abiotic conditions. In general, a positive correlation (r=0.76 to 0.89; P=0.05) was observed between concentration of fungal exudates and attraction of bacterial cells. Similarly, a significant (P=0.05; r=+0.82 to 0.95) positive correlation was noticed between chemotactic response and incubation period. The chemotactic response of bacteria was greatly influenced by temperature and pH of the test fungal exudate. The optimum temperature for maximum chemotaxis was $25^{\circ}C$ for A. radiobacter, $30^{\circ}C$ for B. polymyxa, P. aerugionosa, P. fluorescens and X. malvacearum and $35^{\circ}C$ for B. subtilis. Fungal exudates maintained at pH 7 attracted maximum number of bacteria. The response of bacterial cells to exudates at pH 3 and 11 was not significantly (P=0.05) different than that to the buffer (control). Chemotaxis of bacteria was observed towards attractants (fungal propagules and their exudates) when they were kept apart and bridged with the capillaries filled with non-attractant (buffer) or attractant (exudate).

• The Korean Journal of Mycology
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• v.14 no.1
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• pp.89-91
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• 1986

Sixteen seed samples of nine vegetable crops imported from Japan were tested for plant quarantine by routine methods of seed health testing. Nineteen species of fungi including Alternara alternata were identified from the seed samples. Some species were very frequently detected in the seeds. In this experiment, Verticillium albo-atrum, V. dahliae and Macrophomina sp. from the seeds of spinach, and Cercospora capsici, Drechslera hawaiiensis and V. albo-atrum from the seeds of sweet pepper were detected for the first time, respectively. It has been reported that they had a pathogenicity on some vegetable crops in Japan and other countries. The data suggest that an epidemic damage may be occurred if the infected seeds are sown and cultivated in Korea.

• The Korean Journal of Mycology
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• v.48 no.3
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• pp.297-312
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• 2020

Wilted soybean plants were collected from soybeans cultivation fields in Korea from 2014 to 2016. Fusarium spp., Colletotrichum spp., Rhizoctonia spp., Macrophomina sp., Phytophthora spp., and Calonectria ilicicola were obtained from the infected samples. Out of these, Fusarium spp. were the dominant species (79.1%). In total, 53 isolates were identified as F. solani species complex, F. oxysporum species complex, F. graminearum species complex, and F. fujikuroi species complex based on mycological characteristics. Sequence typing analysis was conducted using translation elongation factor 1 alpha (TEF) to confirm the identification of isolates. All isolates were identified as F. solani, F. oxysporum, F. commune, F. asiaticum, and F. fujikuroi based on phylogenetic analysis of TEF sequences. Pathogenicity of 44 isolates was tested on three cultivars of soybean using the root dip inoculation method. Out of 5 Fusarium species, only F. asiaticum could not cause the symptoms or be weak. Ten isolates were selected based on pathogenic characters and species identification to investigate the host range and screen soybean cultivars for resistance. Fusarium solani, F. oxysporum, and F. commune were aggressive only to soybean, and F. fujikuroi was aggressive to kidney bean, yellow cowpea, black cowpea, adzuki bean as well as soybean. All 13 Korean soybean cultivars were susceptible to F. commune and F. fujikuroi. Out of 13 cultivars, cv. Janggi, cv. Poongsannamul, and cv. Socheongja were resistant to Fusarium wilt, while cv. Hwanggeumol and Chamol were susceptible to Fusarium wilt.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.68-76
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• 2018

Actinobacterial strains isolated from Cow feces were studied for their antifungal attributes against phytopathogens and industrially important enzymes. A total of 30 Actinobacterial strains were obtained from 10 samples of cow feces. All the strains were belonging to the genera Streptomyces on the basis of morphological and chemotaxonomic analysis. During preliminary screening, out of 30 strains, 15 strains (50%) showed antifungal activity against five fungal phytopathogens including Aspergillus niger, Fusarium solani, Fusarium oxysporum, Macrophomina phaseolina and Rhizoctonia solani. While, isolate GBTCF-26 was found to be most active against R. solani with 62.2% inhibition of fungal mycelium, GBTCF-09 was prominent against F. solani and F. oxysporum with percent inhibition of 61.1% and 58.8%, respectively. Out of 30 strains, 19 (63.3%), 16 (53.3%), 11 (36.7%), 10 (33.3%), 4 (13.3%) and 8 (26.7%) strains were producing amylase, caseinase, gelatinase, lipase, chitinase and cellulose, respectively. The selected strains, GBTCF-09, GBTCF-21 and GBTCF-26, were identified as Streptomyces sp. on the basis of their 16S rDNA sequence. The study supports the idea that the Actinobacteria from unique niches (Cow feces) possess the production potential of industrially important enzymes including bioactive molecules.

• Korean journal of applied entomology
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• v.19 no.4 s.45
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• pp.228-233
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• 1980

The infection rate of soybean black root rot disease caused by Calonectria crotalariae was about $14\%$. The isolated fungi from the infected soybean roots and stems were Calonectria crotalariae, Fusarium solani, F. roseum, Phomopsis sojae, Pythium aphanidermatum, Rhizoctonia solani and Macrophomina sp. Among them, C. crotalariae was the most virulent pathogen under the laboratory conditions. Mycelial growth and microsclerotial formation were good on PSA containing 1000cc of water, 100g of potato and 20g of sugar. Mycelial growth, sporulation and microsclerotial formation were good on sterilized root. Perithecial formation was better in the dark condition than in the light. Survival of macroconidia was not available between $0\~25\%$ soil water content. Microsclerotia and mycelium in infected plant debris were survived for 4 months at to $8\%\;50\%$ soil water content. The plant height, when inoculated with $1.2\%$ inoculum density, reached approximately half of uninoculated plants. Disease severity was much higher at nonsterilized soil than completely sterilized soil. It was determined that the host range of this pathogen includes soybean, peanut, green bean and red bean.

• Mycobiology
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• v.45 no.4
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• pp.385-391
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• 2017

The ability of Bacillus subtilis, strain ALICA to produce three mycolytic enzymes (chitinase, ${\beta}$-1,3-glucanase, and protease), was carried out by the chemical standard methods. Bacillus subtilis ALICA was screened based on their antifungal activity in dual plate assay and cell-free culture filtrate (25%) against five different phytopathogenic fungi Alternaria alternata, Macrophomina sp., Colletotrichum gloeosporioides, Botrytis cinerea, and Sclerotium rolfesii. The B. subtilis ALICA detected positive for chitinase, ${\beta}$-1,3-glucanase and protease enzymes. Fungal growth inhibition by both strain ALICA and its cell-free culture filtrate ranged from 51.36% to 86.3% and 38.43% to 68.6%, respectively. Moreover, hyphal morphological changes like damage, broken, swelling, distortions abnormal morphology were observed. Genes expression of protease, ${\beta}$-1,3-glucanase, and lipopeptides (subtilosin and subtilisin) were confirmed their presence in the supernatant of strain ALICA. Our findings indicated that strain ALICA provided a broad spectrum of antifungal activities against various phytopathogenic fungi and may be a potential effective alternative to chemical fungicides.