• The Plant Pathology Journal
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• v.17 no.3
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• pp.180-183
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• 2001

A corynespora leaf spot of pepper, which has not been reported previously in Korea, occurred severely at the major pepper cultivation area of Chinju, Gyeongnam province in 2001. Infection rate ranged from 48.2 to 84.7% in eight fields surveyed. The causal fungus was identified as Corynespora cassicola based on the following cultural and morphological characteristics. The fungi grew well on potato dextrose agar, showing gray to brown color with cultural age. Conidia formed solitary or catenary were obclavate to cylindrical in shape, and pale olivaceous brown or brown in color. They had 420 pseudoseptate and isthmus, and measured 42.7-197.6 x 9.3-$23.5\mu\textrm{m}$. Septate conidiophores were pale to light brown in color, and measured 116.5-836.0 x 4.2-$11.0\mu\textrm{m}$. Conidia germinated as a bi-polar type. Optimal temperature for mycelial growth and conidial germination was $30^{\circ}$ and 25-$30^{\circ}$, respectively. The fungus showed strong pathogenicity to pepper plant, and the symtoms on pepper by the artificial inoculation were similar to those observed in the field. This is the first report on the corynespora leaf spot on pepper (Capsium annuum) caused by Corynespora cassicola in Korea.

• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.87-92
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• 2001

For the biological treatment of industrial wastewater containing high concentration of phenol, isolation and characterization of phenol - degrading bacterium were carried out. A bacterial strain P2 capable of degrading phenol was isolated from contaminated soils by enrichment culture technique and identified as the genus Rhodococcus by morphological, cultural, biochemical characteristics, and Biolog system. The optimal medium composition and cultural conditions for the growth and degradation of phenol by Rhodococcus sp. P2 were 0.1% of (NH$_4$)$_2$SO$_4$, 0.2% of KH$_2$PO$_4$, 0.25% of Na$_2$HPO$_4$ㆍ12$H_2O$, 0.2% of MgSO$_4$ㆍ7$H_2O$, and 0.008% of CaC1$_2$ㆍ2$H_2O$ along with initial pH 8.5 at 3$0^{\circ}C$. Rhodococcus sp. P2 could grow with phenol as the sole carbon source up to 1,800 ppm in batch cultures, but did not grow in medium containing above 2,000 ppm of phenol. When 800 ppm phenol was given in the optimal media, Rhodococcus sp. P2 completely degraded it within 24 h. Meanwhile, 1,800 ppm of phenol was degraded within 9 days. Rhodococcus sp. P2 could utilize toluene, n-hexane, xylene and benzene as sole carbon source .

• The Korean Journal of Mycology
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• v.52 no.2
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• pp.145-153
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• 2024

While investigation of the fungal diseases on apples collected from Cheongsong-gun and Bonghwa-gun in Gyeongbuk province, Korea, between August and September 2023 isolated five fungal strains from fruits with sooty blotch and flyspeck (SBFS) disease. The strains were designated as KNUF-23-CS02, KNUF-23-CS-06, KNUF-23-CS12, KNUF-23-BH01, and KNUF-23-BH03. When grown on potato dextrose agar and 2% water agar, the cultural characteristics of the strains were similar to those previously reported characteristics of Peltaster fructicola Pf001. The strains produced monoblastic, hyaline conidiogenous cells; the conidia were hyaline, unicellular, cylindrical to ovoidal, and 3.5-7×1.7-3.9 and 4.0-6.6×1.8-3.2 μm in size on synthetic nutrient-poor agar or water agars, respectively. Secondary conidia production by microcyclic conidiation and budding was observed. The KNUF-23-BH03 strain was shown to cause SBFS symptoms similar to those observed on the apples in the pathogenicity test. Molecular phylogenetic analyses were conducted based on the isolated species sequences of the internal transcribed spacer region, nuclear large ribosomal DNA subunit, and mitochondrial small ribosomal RNA subunit gene. The five strains were clustered with Peltaster fructicola Pf001. Based on the cultural and morphological characteristics and phylogenetic analysis, the five strains were identified as Peltaster fructicola, which has not been previously reported in Korea.

• The Korean Journal of Mycology
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• v.42 no.2
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• pp.170-173
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• 2014

Two unrecorded yeasts, Meyerozyma caribbica UL5-1 and Pichia silvicola UL6-1 were screened from 58 yeasts which were isolated from wild flowers in Ulleungdo in Gyeongsangbuk-do, Korea. The morphological and cultural characteristics of these unrecorded yeasts were investigated. Both yeasts were oval in shape and formed pseudomycelia. P. silvicola UL6-1 formed ascospore, but M. UL5-1 did not. P. silvicola UL6-1 and M. caribbica UL5-1 also grew in vitamin-free medium and 5% NaCl-containing yeast extract-peptone-dextrose medium. The two unrecorded yeasts assimilated glucose, galactose, xylose, cellobiose, trehalose, glycerol and sorbitol, and also fermented glucose, fructose and mannose. The supernatant of both M. caribbica UL5-1 and P. silvicola UL6-1 showed high antihypertensive angiotensin I-converting enzyme inhibitory activity of 84.2% and 82.6%, respectively. Cell-free extract of P. silvicola UL6-1 also showed very high anti-diabetic ${\alpha}$-glucosidase inhibitory activity (85.8%).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.411-434
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• 1982

Yield loss of wheat and barley due to meteorological constraints has been analyzed in order to get the basic information, which will lead to the counter-measures for dissemination of agricultural technology and administration. These meteorological damages were analyzed on the results of percentage yield loss and mechanism of damage and the aspects of constraints were explained. The annual yield loss of wheat and barley were 21.7% by meteorological stress: Cold damage, 5.9% ; excessive soil moisture, 5.6% ; lodging, 2.9% ; drought, 3.0% ; disease, 4.3% etc. Those damages by the stresses mentioned above and rain damage were analyzed in relation to the growth stages and the degrees of damage. The predispositions and the growth of wheat and barley to those meteorological stress are also discussed. Varietal resistances of wheat and barley to those stresses were indexed and the physiological and morphological characteristics of these resistant cultivars are described. Cultural practices to minimize the damages were also reviewed.

• The Plant Pathology Journal
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• v.20 no.3
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• pp.192-195
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• 2004

A survey on ornamental diseases in 2000 and 2001 showed frequent occurrence of blight symptoms on leaves and stems of columbine and bleeding heart in botanical gardens of Gangwon and Chungnam provinces in Korea. A total of 65 isolates of Streptobotrys sp. were obtained from the infected leaves and stems of the two plants. All isolates were identified as Streptobotrys caulophylli based on their morphological and cultural characteristics. Blight symptoms were induced on leaves of the two plants by artificial inoculation with the isolates. This is the first report that S. caulophylli causes leaf and stem blight on columbine and bleeding heart in the world.

• Mycobiology
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• v.47 no.3
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• pp.261-272
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• 2019

Oomycetes are widely distributed in various environments, including desert and polar regions. Depending upon different habits and hosts, they have evolved with both saprophytic and pathogenic nutritional modes. Freshwater ecosystem is one of the most important habitats for members of oomycetes. Most studies on oomycete diversity, however, have been biased mostly towards terrestrial phytopathogenic species, rather than aquatic species, although their roles as saprophytes and parasites are essential for freshwater ecosystems. In this study, we isolated oomycete strains from soil sediment, algae, and decaying plant debris in freshwater streams of Korea. The strains were identified based on cultural and morphological characteristics, as well as molecular phylogenetic analyses of ITS rDNA, cox1, and cox2 mtDNA sequences. As a result, we discovered eight oomycete species previously unknown in Korea, namely Phytopythium chamaehyphon, Phytopythium litorale, Phytopythium vexans, Pythium diclinum, Pythium heterothallicum, Pythium inflatum, Pythium intermedium, and Pythium oopapillum. Diversity and ecology of freshwater oomycetes in Korea are poorly understood. This study could contribute to understand their distribution and ecological function in freshwater ecosystem.

• Mycobiology
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• v.51 no.5
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• pp.333-342
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• 2023

Phytophthora species, classified under Oomycota, cause significant damage to various crops and trees. The present study introduced Phytophthora species, P. nagaii and P. tentaculata, new to Korea, which pose notable risks to their respective host plants. Our research provided a comprehensive description of these species taking into account their cultural features, morphological characteristics, and molecular phylogenetic analysis using the internal transcribed spacer rDNA region and cytochrome c oxidase subunit mtDNA genes (cox1 and cox2) sequences. In addition, this study first evaluated the sensitivity of P. nagaii and P. tentaculata to five anti-oomycete fungicides, finding both species most responsive to picarbutrazox and P. tentaculata resistant to fluazinam. The data can guide targeted treatment strategies and offer insights into effective control methods. The findings expand our understanding of the diversity, distribution, and management of Phytophthora species in Korea.

• Microbiology and Biotechnology Letters
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• v.23 no.4
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• pp.405-410
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• 1995

In order to screen dextranase with high dextranolytic activity from microbial origins, dextranase producing fungal isolates were isolated from soil of the Taeion area. 197 strains with dextranolytic activities were isolated, out of which 3 strains with high dextranolytic activities were selected in the first screening. A strain (GR-98) with a best dextranolytic activity was selected in the second screening. The strain was identified to be similiar Aspergillus ustus by the morphological and cultural characteristics. The optimum culture temperature and initial pH for the dextranase production of the strain was 30$\circ$C and 7.0, respectively. The optimum culture medium was composed of 2% dextran, 0.3% KNO$_{3}$, 0.05% K$_{2}$HPO$_{4}$, 0.02% MgSO$_{4}$-7H$_{2}$O, 0.05% KC1, and 2.5 $\mu$g/ml pyridoxamine, and the enzyme production was maximum when the strain was subcultured at 30$\circ$C for 7 days.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.294-296
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• 2000

Anthracnose symptoms were frequently found on stems of Indian fig cactus in Cheju island of Korea in 1998 and 1999. Typical symptoms were gray to black dry rot of stems with concentric arrays of dot-like spots. A Glomerella sp. or a Colletotrichum sp. was frequently isolated from the symptoms, both of which were identified as Glomerella cingulata and its anamorph, Colletotrichum gloeosporioides based on their morphological and cultural characteristics. Out of 31 isolates obtained from the symptoms, 12 isolates were the anamorph producing only conidia, four isolates the telemorph producing only ascospores, and 15 isolates the holomorph producing both spores on potato dextrose agar. Stem rots similar to the original anthracnose symptoms were induced by wound inoculation of conidia and ascospores but not by non-wound inoculation. The anamorphic isolates caused more extensive stem rot than the telemorphic and holomorphic ones.