• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.571-579
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• 2004

In order to obtain the genetic informations of the Korean isolates of porcine circovirus 2 (PCV2), nucleotide sequences of total genome of three isolates and open reading frame 2 (ORF2) of four isolates were determined and compared with those of other reference PCV2 isolates. Nucleotide sequences of 3 isolates showed over 99% homology with those of reference strain (GenBank accession no. AF027217). Point mutations were mainly determined on ORF2 regions but little on ORF1 regions. The patterns of pointmutated sites and nucleotide substitution on ORF2 regions were generally consistent between Korean isolates, and these mutated sites observed in Korean isolates were also relatively similar to those of foreign isolates. Phylogenetic analysis of nucleotide or amino acid sequences showed that there were minor branches consisting of three clusters; cluster of Korea, Canada and America, cluster of Spain and Taiwan, and the last cluster of French and China isolates. These results suggested that Korean PCV2s were probably originated from North America such as Canada or USA. The genetic informations obtained from this study could be useful for the research of diagnosis and pathogenecity of PCV2.

• Mycobiology
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• v.32 no.1
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• pp.17-23
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• 2004

Growth of ten isolates of Catenaria anguillulae on linseed oil-cake agar medium was studied at 10, 13, 15, 20, 25, 30, 35, 40, 44 and $46^{\circ}C$. The cardinal temperatures of these isolates were also determined. Observations clearly revealed that the isolates differed in their temperature requirements. Isolate GA was found to grow best at $40^{\circ}C$, whereas VF isolate showed best growth at 35 and $40^{\circ}C$. Isolates PA, KA, CHP, KO, MA and SWP grew best at $35^{\circ}C$. The other isolates(KP and MMT) showed their best growth at $30^{\circ}C$. Based on radial growth, isolates were categorized as fast growing, medium growing and slow growing. Studies on effect of different temperatures on pathogenicity was made using only three isolates: VF, KP and MA against Xiphinema basin. VF isolate caused maximum infection at $40^{\circ}C$, whereas KP and MA isolates caused maximum infection at $30^{\circ}C$. The morphology of sporangia varied with temperature in isolates producing elongate-elliptical or filamentous sporangia. In VF isolate the sporangia were largely iilamentous to elongate elliptical at $30^{\circ}C$. The width of the sporangia increased with increasing and decreasing temperatures. At $44^{\circ}C$ the sporangia of this isolate were mostly broadly elliptical or spherical. This clearly indicates that sporangia vary in morphology with temperature. From the morphometrical studies it was understood that sporangial morphology was more consistent and reliable for grouping of isolates. Based on the morphology of sporangia the isolates of C. anguillulae were characterized in three groups viz., Mamentouslelongate elliptical(VF, KA, GA and SWP), spherical(PA, KP, MA and MMT) and vertically elongate sporangia(CHP and KO).

• The Plant Pathology Journal
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• v.28 no.3
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• pp.270-281
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• 2012

The bacteria B1-9 that was isolated from the rhizosphere of the green onion could promote growth of pepper, cucumber, tomato, and melon plants. In particular, pepper yield after B1-9 treatment on the seedling was increased about 3 times higher than that of control plants in a field experiment. Partial 16S rDNA sequences revealed that B1-9 belongs to the genus Pantoea ananatis. Pathogenecity tests showed non-pathogenic on kimchi cabbage, carrot, and onion. The functional characterization study demonstrated B1-9's ability to function in phosphate solubilization, sulfur oxidation, nitrogen fixation, and indole-3-acetic acid production. To trace colonization patterns of B1-9 in pepper plant tissues, we used $DRAQ5^{TM}$ fluorescent dye, which stains the DNAs of bacteria and plant cells. A large number of B1-9 cells were found on the surfaces of roots and stems as well as in guard cells. Furthermore, several colonized B1-9 cells resided in inner cortical plant cells. Treatment of rhizosphere regions with strain B1-9 can result in efficient colonization of plants and promote plant growth from the seedling to mature plant stage. In summary, strain B1-9 can be successfully applied in the pepper plantation because of its high colonization capacity in plant tissues, as well as properties that promote efficient plant growth.

• Journal of Microbiology and Biotechnology
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• v.21 no.2
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• pp.192-196
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• 2011

Microbial induction of rusty-root was proved in this study. The enzymes hydrolyzing plant structural materials, including pectinase, pectolyase, ligninase, and cellulase, caused the rusty-root in ginseng. Pectinase and pectolyase produced the highest rusty-color formation. Ferrous ion ($Fe^{+++}$) caused the synergistic effect on rusty-root formation in ginseng when it was used with pectinase. The effect of ferric ion ($Fe^{++}$) on rusty-root formation was slow, compared with $Fe^{+++}$, probably due to gradual oxidation to $Fe^{+++}$. Other metal ions including the ferric ion ($Fe^{++}$) did not affect rusty-root formation. The endophytic bacteria Agrobacterium tumefaciens, Lysobacter gummosus, Pseudomonas veronii, Pseudomonas marginalis, Rhodococcus erythropolis, and Rhodococcus globerulus, and the rotten-root forming phytophathogenic fungus Cylindrocarpon destructans, caused rusty-root. The polyphenol formation (rusty color) was not significantly different between microorganisms. The rotten-root-forming C. destructans produced large quantities of external cellulase activity (${\approx}2.3$ U[${\mu}m$/min/mg protein]), which indicated the pathogenecity of the fungus, whereas the bacteria produced 0.1-0.7 U. The fungal external pectinase activities (0.05 U) and rusty-root formation activity were similar to those of the bacteria. In this report, we proved that microbial hydrolyzing enzymes caused rusty-root (Hue value $15^{\circ}$) of ginseng, and ferrous ion worsened the symptom.

• Research in Plant Disease
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• v.9 no.4
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• pp.221-223
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• 2003

In May 2002, a destructive stem rot of Obedient plant (Physostegia virginiana) occurred sporadically in an exhibition farm of Hamyang-gun, Gyeongsangnam-do Agricultural Research and Extension Services, Korea. The typical symptoms of the disease were stem rot, crown rot, wilt or blight. Upper parts of the infected stems were mostly blighted. White mycelial mats were spread over lesions and the sclerotia were formed on the stems near soil line. The sclerotia was globoid or irregular in shape, 1${\sim}$3 mm in size, and brown in color. The optimum temperature for fungal growth was about $30^{\circ}C$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA, and hyphal diameter was 3.6${\sim}$9.4 ${\mu}m$. On the basis of mycological characteristics and test of pathogenecity to host plants, the fungus was identified as Sclerotium rolfsii. This is the first report on the stem rot of Physostegia virginiana caused by Sclerotium rolfsii in Korea.

• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.77-79
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• 1975

Brown rot of eggplant caused by Phytophthora capsici has not been reported so far in Korea. The wide distribution of the disease was found at the central Korea including Suweon. The symptom of the disease was characterized by water sealing lesions at first, the color gradually turn brown and a little sunken area on the fruit appearred at the final stage. Dense hyphae and short sporangiophores grew out from the lesions, and they produce abundant zoosporangia on them. The disease was identified from buck-eye rot caused by Phytophthora parasitica in that the cottony growth of hyphae and rare zoosporangia formation. The pathogen was isolated and indentified on the basis of the pathogenecity and morphology comparing with P. parasitica.

• Research in Plant Disease
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• v.10 no.1
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• pp.21-24
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• 2004

A destructive stem rot of pepper (Capsicum annuum) was found from the often field sporadically in Jingyemyon, Hadong-gun in July 2002 and vinyl houses in Moonsan-eup, Jinju City in October 2003. The same fungus also caused collar and crown rot and systemic wilt or blight of whole plant. White mycelium spread over stems of infected plants and sclerotia formed on the old lesions and near the soil surface. The fungus showed maximum mycelial growth around 3$0^{\circ}C$. The mycelial color is white and width of hyphae ranges 3.6∼10.2 ${\mu}{\textrm}{m}$, and formed clamp connection. Numerous sclerotia were farmed in artificial media such as PDA at 3$0^{\circ}C$. The shape of sclerotia were sphere and 1.0∼2.1 mm in diameter, The fungus was isolated repeatedly from the infected tissues and the pathogenecity of fungus to pepper (Capsicum annuum) was confirmed, and identified as Sclerotium rolfsii. This is the first report on the stem rot of pepper (Capsicum annuum) caused by Sclerotium rolfsii in Korea.

• Research in Plant Disease
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• v.8 no.4
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• pp.215-219
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• 2002

Fruit rot of pomegranate (Punica granatum) caused by Coniella granati were observed in several farmer's fields in Gwangdo-myon, Tongyeong City, Gyeongnam Province, Korea. The symptoms occurred on fruit with rotting then eventually dropping and mummification. The colony color of causal fungus was whitish on potato dextrose agar. Conidia were single celled, pale brown or olive in color at maturity, straight or slightly curved fusiform in shape, and were 10.3~17.4$\times$2.8~4.0 ${\mu}{\textrm}{m}$ in size. Conidiogenous cell were hyaline, branched only at the base aseptate, elongate, phialidic, enteroblastic and 12.4~1.4$\times$2.8~3.6 ${\mu}{\textrm}{m}$ in size. Pycnidia were black in color and globose in shape and 124.6~228.4 ${\mu}{\textrm}{m}$ in size. Optimum temperature for mycelial growth was $25^{\circ}C$. On the basis of mycological characteristics and pathogenecity test on host plants, the fungus was identified as Coniella granati. This is the first report on the fruit rot of pomegranate caused by Coniella granati in Korea.

• The Korean Journal of Mycology
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• v.28 no.1
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• pp.46-48
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• 2000

The gray mold disease was severely occurred on safflower grown in experimental farm of Kyongsangnam-do Agricultural Research and Extension Services in 1999. At first, the infected leaves discolored gray or dark from the tip and gradually expanded to downword. The fungus also attacked stem, pod and calyx. The infected area became dark and dried, and frequently gray mold grown on the infected area. The causal organism was isolated and proved its pathogenecity according to Koch's postulate. Conidia of the fungus in mass were hyaline or gray, 1-celled, mostly ellipsoid or ovoid and sized $7.4{\sim}16.8{\times}5.3{\times}10.4\;{\mu}m$. Conidiophores were observed with their wide size of $2.9{\times}15.5\;{\mu}m$. The temperature range for mycelial growth was between $5^{\circ}C\;and\;30^{\circ}C$ with the optimum temperatures of $20^{\circ}C\;and\;25^{\circ}C$. The causal organism was identified as Botrytis cinerea and based on mycological characteristics examined. This is the first report on gray mold of safflower caused by Botrytis cinerea in Korea.

• The Korean Journal of Mycology
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• v.31 no.2
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• pp.117-119
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• 2003

A stem rot of eggplant (Solanum melongena) was found in experimental field of Gyeongsangnam-do Agricultural Research and Extension Services, Korea. The typical symptoms of the disease were stem rot, crown rot, wilt or blight. Upper parts of the infected stems were mostly blighted and white turf of fungal mycelium mats was spread over lesions. Sclerotia were farmed on the stems near soil line. The sclerotia of the fungus eadily were produced in artificial media such as PDA at $30^{\circ}C$. The sclerotia were globoid, $1.0{\sim}3.4mm$ in diameter and brown in color. The optimum temperature for growth of the fungus was about $30^{\circ}C$. The typical clamp connections were found in the hypha formed on PDA, and was $3.8{\sim}10.6{\mu}m$ in size. On the basis of mycological characteristics and pathogenecity test, the fungus was identified as Sclerotium rolfsii. This is the first report of stem rot of eggplant caused by Sclerotium rolfsii in Korea.