• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.449-453
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• 1990

This study was attempted to obtain the efficient milk-clotting enzyme from microorganisms as a rennet subtitute. Fungi which showed the formation ability of the milk-clotting enzyme were selected out from samples of soil hay and wastes etc. Among these isolated fungi, strain no. C-7 which had presented higher value in the ratio of milk-clotting activity to proteolytic activity was selected. The hyphae of this strain was white to gray and no septa. A single sporangiophore which stand erectly above growing hyphae was monomucor type without branching. A globose sporangium was developed at the tip of each sporangiophore. The suitable temperature and pH for the growth of no. C-7 was 20-$30^{\circ}C$ and pH 3.0-8.0 respectively. These morphological and physiological characteristics implied that strain no. C-7 was Mueor mucedo.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.354-356
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• 2001

In August 2001, pod rot of cowpea caused by Choanephora cucurbitarum was found in the experimental fields of the Gyeongsangnam-do Agricultural Research and Extension Services, Korea. Initial symptoms of the disease were the appearance of water-soaked, dark-green lesions and followed by rapid rotting of the infected tissues. As the disease progressed, whitish mycelia and monosporous sporangiophore with monosporous sporangiola were produced on the lesions. The fungus produced white to pale yellowish brown mycelia with scattered monosporous sporangiophore and monosporous sporangia containing sporangiospores on potato dextrose agar (PDA). Monosporous sporangiophore was long, slender and branched at the apex, with each branch bearing a sporangiospore. Sporangium was subglobose in shape and 42.6-112.6 ㎛ in size. Monosporous sporangiola were elliptic, fusiform or ovoid, brown in color, and 9.8-23.4$\times$7.2-12.8 ㎛ in size. Sporangiospores were elliptic, fusiform or ovoid in shape, dark brown or brown in color, 12.9-24.6$\times$8.6-15.4 ㎛ in size, and had three or more appendages. Zygospores were black and 43.6-72.4 ㎛ in size. The fungus grew on PDA at 15-40$\^{C}$, and optimum temperature was 30$\^{C}$. This is the first report on pod rot of cowpea caused by C. cucurbitarum in Korea.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.230-234
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• 1993

In order to isolate mutants in Rhizopus nigricans, the optimal treatment conditions for the chemical mutagens, N-Methyl-N'-Nitro-N-Nitrosoguanidine(MNNG) and Ethyl Methane Sulphonate(EMS), were explored. When MNNG was used as the chemical mutagen, the optimum concentration and treatment time for the best mutation frequency were $125{\mu}g/ml$ and 60 minutes, respectively. Under the optimum conditions for MNNG, the survival rate was 0.1-1.0%. The leucine auxotroph could be isolated. The phenotypic characteristics of the three mutants prepared are as follows; shortened sporangiophore, spiral sporangiophore, and reduced size of sporangium and sporangiospore. However, EMS as the chemical mutagen was ineffective for this species.

• The Plant Pathology Journal
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• v.20 no.4
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• pp.235-239
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• 2004

Phytophthora rot on sword bean, Canavalia gladiata, which has not been reported yet in Korea, occurred in some fields of Jinju in 2003. The disease develops on the basal stem of the plant, but is also often observed on leaves and pods. Rot lesions begin with small dark brown spots and as these are water-soaked, they enlarge rapidly. The magnitude of at the field reached 40%. Abundant sporangia of Phytophthora were formed on the surface of diseased pods and were mummied later. The causal fungus was identified as P. nicotianae with the following mycological characteristics: Sporangium-readily formed in water, papillate, noncaducous, ovoid to spherical, 24-58 (L) ${\times}$ 22-35 (W) in size; Oogonium-spherical, smooth walled, and 22-30; Oospore- aplerotic, spherical, and 18-24; Antheridium- amphigynous, unicellula, and spherical; Chlamydospore- abundant, spherical, and 25-35; Sexuality- heterothallic, and A1 or A2; Optimum growth temperature- about 28$^{\circ}C.$ The fungus showed strong pathogenicity to sword bean. Symptoms similar to those observed in the fields appeared 2 days and 4 days after inoculation with and without wound on pods. This is the first report of Phytophthora rot of sword bean in Korea.

• Mycobiology
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• v.33 no.3
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• pp.163-165
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• 2005

In April 2002 and 2003, soft rot on fruit of eggplant (Solanum melongena) caused by Choanephora cucurbitarum was observed in the experimental fields at Gyeongnam Agricultural Research and Extension Services in Korea. The disease began with water-soaking and dark-green lesions, and then the infected tissues were rapidly rotten. Sporangium was subglobose in shape and sized $40{\sim}130\;{\mu}m$. Monosporous sporangiola were elliptic, fusiform or ovoid, brown in color, and measured as $12{\sim}20\;{\times}\;6{\sim}14\;{\mu}m$. Sporangiospores having three or more appendages were elliptic, fusiform or ovoid in shape, dark brown or brown in color, and sized $14{\sim}20\;{\times}7{\sim}16\;{\mu}m$. The fungus grew well on potato dextrose agar between 15 and $40^{\circ}C$ and its optimum growth temperature was $30^{\circ}C$. Based on morphological characteristics, the causal fungus of the fruit soft rot of eggplant was identified as C. cucurbitarum. This is the first report on the soft rot of S. melongena caused by C. cucurbitarum in Korea.

• Mycobiology
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• v.43 no.1
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• pp.63-70
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• 2015

Phytophthora diseases have become a major impediment in the citrus production in Thailand. In this study, an isolate of Phytophthora denominated as PHY02 was proven to be causal pathogen of root rot of Pomelo (Citrus maxima) in Thailand. The isolate PHY02 was morphologically characterized and identified as Phytophthora palmivora based on molecular analysis of an internal transcribed spacer rDNA sequence. This work also presents in vitro evaluations of the capacities of Chaetomium spp. to control the P. palmivora PHY02. As antagonists, Chaetomium globosum CG05, Chaetomium cupreum CC3003, Chaetomium lucknowense CL01 inhibited 50~61% mycelial growth, degraded mycelia and reduced 92~99% sporangial production of P. palmivora PHY02 in bi-culture test after 30 days. Fungal metabolites from Chaetomium spp. were tested against PHY02. Results showed that, methanol extract of C. globosum CG05 expressed strongest inhibitory effects on mycelial growth and sporangium formation of P. palmivora PHY02 with effective dose ED50 values of $26.5{\mu}g/mL$ and $2.3{\mu}g/mL$, respectively. It is interesting that C. lucknowense is reported for the first time as an effective antagonist against a species of Phytophthora.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.458-462
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• 1998

Stem rot symptomof lily caused by Phytophthora was observed in Chilkok, Korea in 1997. Oogonia of Phytophthora were abundantly developed on epidermal tissues of stem and leaves of the diseased plants. The casual fungus was identified as Phytophthora cactorum based on their cultural and morphological characteristics. Sporangia were markedly papillate and the shape was broadly spherical to ovoid both on agar and in water. The size was 28~44$\times$20~28 ${\mu}{\textrm}{m}$ (av. 36~24) and a short pedicel was attached to each sporangium. The fungus was homothallic and oogonia were 28~32 ${\mu}{\textrm}{m}$ (av. 30) in size and slightly yellow. Antheridia were paragynous and spherical or irregularly club shaped. Optimal temperature for mycelial growth was 25~27$^{\circ}C$. The fungus did not grow under 6$^{\circ}C$ and over 34$^{\circ}C$. The fungus was highly pathogenic to three cultivars of lily. Symptom was developed at 4-day after artificial inoculation with zoospores (103 cell/ml) on the stem of lily. The symptom was identical to those produced by natural infection in the field and the plant was blighted within 14 days after inoculation.

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.238-243
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• 1987

In this study, an acidoduric Streptomyces strain was isolated and identified from acidic forest soil around Dankook University, Cheonan Campus. This isolated strain had rod-shaped, smooth, non-motile spore and the shape of spore chain was compact spiral. This structure appeared similar to the sporangium of the genus Streptosporangium but this strain proved to be a Streptomyces strain by an electron microscopic study and cell wall analysis. This strain showed a best growth on neutral medium, was also able to grow on the acidic media of pH 4.0 and pH 5.0. The color determination of this strain on various agar media and other physiological tests were carried out by ISP-methods. From these results, the isolated strain was considered to be Streptomyces mirabilis.

• Korean Journal Plant Pathology
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• v.13 no.3
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• pp.139-144
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• 1997

A destructive collar rot of apple caused by a species of Phytophthora has widely occurred in Kyungbuk and less extended in Chungbuk, Chungnam and Chunbuk provinces of Korea. Significantly higher incidence of the disease was observed on cv. Fuji when M26 or M9 was used as dwarfing stocks. Incidence of the disease at several orchards in Uisung, Kunwi, Yesan and Muju ranged from 45 to 80%. Twenty-five isolates of the causal fungus were collected and all isolates were identified as P. cactorum on the basis of their cultural and morphological characters. The fungus produced markedly papillate and broadly ovoid deciduous sporangia both on agar and in water, and a short pedicel was attached to each sporangium. Oospores were readily formed on clarified V8 agar by single isolates and all the antheridia were paragynous. The fungus neither grew nor produced oospores under 5 and over 33$^{\circ}C$. The destructive collar rot of apple caused by P. cactorum has not been reported in Korea previously.

• Research in Plant Disease
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• v.13 no.3
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• pp.207-210
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• 2007

A stem and root rot disease of English ivy (Hedera helix) was found in the flower market, Jeonju, Chonbuk province, Korea in May 2007. A Phytophthora species was isolated from the diseased part of the plant. Based on the mycological properties and pathogenesis the isolate was identified as Phytophthora cinnamomi. The fungus produce ovoid sporangium which was ovoid to spherical and obpyriform which is noncaducous, non-papillate and averaged $33.8{\times}16{\mu}m$ in dimension. Chlamydospores were abundantly produced on agar media and sized about $19.7{\mu}m$ in diameter. The fungus was heterothallic and A1 mating type. Oospores were measured $26.2{\mu}m$ in size. Optimum temperature for growth of the fungus was 25 to $30^{\circ}C$. Up to our knowledge, this is the first report demonstrating the stem rot on English ivy caused by P. cinnamomi in Korea.