• Journal of the Korean Society of Tobacco Science
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• v.19 no.1
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• pp.11-17
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• 1997

A flue-cured tobacco variety (Nicotiana tabacum cv. Wisconsin) was used for Plant transformation with the complementary DNA (cDNA) of potato virus Y-necrosis strain (PVY-VN) replicase gone (Nb) which was synthesized through reverse-transcription Primed with oligo(dT) and Polymerization using RNase H-digested template. The cDNA was cloned into Plant expression vector Plasmid (PMBP2), and introduced into tobacco plants by co-culturing tobacco leaf disks with Agrobacterium tumefaciens LBA4404 containing the plasmid before Plant regeneration. Eight Plants, in which the inserted cDNA fragment was detected by Polymerase chain reaction (PCR), out of 70 putative transformants inserted with sense-oriented Mb cDNA showed no symptom at 3 weeks after inoculation, while the other 62 plants, and all plants with vector gone only and antisense-oriented NIb cDNA had susceptible vein-necrosis symptoms. However, only 2 of the 8 resistant plants were highly resistant, which remained symptomless up to 10 weeks after inoculation. Among the first progenies (T1) from self-fertilized seeds of the two resistant transgenic plants, less than 10 % of 71 plants appeared highly resistant (with no symptom), 70% moderately resistant (with mild symptoms on 1 - 2 leaves), and about 20% susceptible (with susceptible symptoms on 3 or more leaves) at 3 weeks after inoculation. These results suggest that the PVY resistance was inherited in the 71 generation. Key words : potato virus Y. viral replicase gene, transgenic tobacco Plants, resistance.

• Research in Plant Disease
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• v.21 no.1
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• pp.40-43
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• 2015

Bacterial pustule of soybean is caused by Xanthomonas axonopodis pv. glycines, one of the most important diseases in soybean. The symptom of bacterial pustule is mainly distributed around leaf veins. However, the reason has not been known. In order to determine pathosystem of bacterial pustule in leaf, soybean leaves were collected and observed using scanning electron microscopy (SEM) and light microscopy. Many hairs were observed at abaxial sides of the leaf, few hairs were observed at tissue around the leaf veins. In addition, unidentified bacterial cells and dusts at the no hair part near veins were observed. In the inoculation assays, the cells of X. axonopodis pv. glycines were observed near leaf veins. The imprint of underside of soybean leaves inoculated with X.axonopodis pv. glycines on PDA showed that the growth of bacteria around veins was observed but no bacterial growth at the part with leaf hairs. Our data demonstrated that soybean leaf hairs play an important role as a physical barrier for structural resistance of soybean against bacterial pustule pathogen.

• Journal of Plant Biology
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• v.32 no.3
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• pp.137-144
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• 1989

In order to clarify the effect of the associative nitrogen fixing bacteria on the growth of corn(Zea mays L. Suwon19), we inoculated corn seedlings with Azospirillum amazonense Y1, a micro-aerobic and acid-tolerant nitrogen fixer, and analyzed the growth and dry matter production and changes of nitrogen and phosphorus quantity of the plant during the growing period. The inoculation of associative N-fixing bacgteria increased the growth of height, leaf area, dry weight and total nitrogen quantity of the plant by 15.4%, 65.4%, 33.7% and 38.0%, respectively, on the day of 56th after sowing. Especially the inoculation of A. amazonense Y1 showed two to three-fold accumulation of phosphorus in each organ of plant. The associative bacteria accelerated the growth of the under ground parts more than those of the upper ground parts of corn plant, and caused decrease in T/R ratios.

• Journal of Mushroom
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• v.18 no.3
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• pp.208-213
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• 2020

Burkholderia contaminans PSB-A and Burkholderia ambifaria PSB-B were isolated from button mushroom bed to estimate their phosphate solubility. The phosphate-solubilizing abilities of these strains were assessed by measuring the phosphorus content in a single and co-inoculation medium for 7 days. The co-inoculation of these two strains released the highest content of soluble phosphorus (166.3 ㎍ mL^-1) into the medium, followed by single inoculation of B. contaminans PSB-A (143.73 ㎍ mL^-1) and B. ambifaria PSB-B (127.1 ㎍ mL^-1). The highest pH reduction, organic acid production, and glucose consumption were also observed in the co-inoculation medium. According to the plant growth promotion bioassay, co-inoculation enhanced the growth of romaine lettuce much more than the single inoculation (20.4% for leaf widths and 16.6% for root lengths). Although no significant difference was noted between single and co-inoculation of bacterial strains in terms of phosphorous release and plant growth, co-inoculation of PSB may have a beneficial effect on crop growth due to a synergistic effect between the strains.

• Mycobiology
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• v.38 no.1
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• pp.78-80
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• 2010

Leaf spot symptoms were frequently observed on yam plants grown in the Yeoju area in Korea during a disease survey in 2008. A total of five isolates of Pseudophloeosporella sp. were obtained from the infected leaves of yam plants. All of the isolates were identified as Pseudophloeosporella dioscoreae based on their morphological and cultural characteristics. A phylogenetic tree derived from the internal transcribed spacer sequences of the fungal isolates showed that the fungus is distinctly separated from species in other related genera. P. dioscoreae isolates caused very tiny spots on leaves of yam plants two weeks after artificial inoculation which were similar to those observed in the field. This is the first report that Pseudophloeosporella dioscoreae causes leaf spot in yams in Korea.

• Research in Plant Disease
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• v.9 no.3
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• pp.166-169
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• 2003

Occurrence of cercospora leaf spot by Cercospora capsici is assamed to remarkbly cause the yield reduction through the leaf spot, yellowing of leaves and early defoliation in pepper cultivation. To develop resistant cultivar, optimal screening conditions of pepper against cercospora leaf spot were studied. Optimal screening conditions were 3.4 ${\times}$ $10^5$ conidia/ml conidial suspension were sprayed on to the leaves of 30~40 days old pepper seedlings, incubated at 15~$20^{\circ}C$/20~$25^{\circ}C$(day/night) and examined 20 days after inoculation.

• 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.

• The Plant Pathology Journal
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• v.27 no.2
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• pp.183-186
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• 2011

During the summer of 2005, specimens of soybean cultivars (Daepung, Daewon, Hwanggeum and Taegwang) showing frogeye leaf spot (FLS) were obtained from various areas in Korea. Eight isolates identified as Cercospora sojina were inoculated on the adaxial leaf surfaces of 63 Korean soybean cultivars; the disease responses to each isolate were evaluated 14 days and 21 days after inoculation. Based on the disease responses (resistant or susceptible) of the cultivars by the isolates, a set of cultivars (Anpeong, Bogwang, Cheongdu No. 1, Cheongja No. 3, Dachae, Daemang, Jangwon, Namhae, Sowon, Taegwang) were selected and inoculated with seven isolates for further testing pathogenic variance. Interestingly, 6 out of 7 tested C. sojina isolates revealed differential ability in infecting different soybean cultivars. This result may indicate the possibility of new race occurrence or pathogenic variation; this also presents evidence for prevalent FLS occurrence during humid and hot weather in Korea.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.408-416
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• 2010

To evaluate the effectiveness of AMF on the growth of horticultural crops, we compared mycorrhizal and non-mycorrhizal plants, perilla (P. frutescens Britt.), that were inoculated with AMF propagules. In the early stages of growth of perilla, compared to the AMF- perilla seedlings, in AMF+ perilla seedlings at 3 weeks after sowing, leaf length and width increased 17% and 29%, leaf area increased 28%, and shoot fresh weight increased 33%, root total length increased 1%, and chlorophyll content increased 3%. Further at 10 weeks after sowing, compared to the AMF- perilla plants, in perilla plants inoculated with AMF at the sowing and transplanting stages, leaf area increased 21% and 19%, shoot length increased 19% and 17%, root fresh weight increased 17% and 20%, and chlorophyll content increased 5.1% and 4.8%, respectively. Moreover, at 14 weeks after sowing, compared to the AMFperilla plants, in perilla plants inoculated with AMF at the sowing and transplanting stages, the number of leaves increased 16% and 20%, root fresh weight increased 16% and 17% significantly. Further, leaf fresh weight increased 9% and 11%, shoot diameter increased 4.5% and 7.3%, and chlorophyll content increased 1.5% and 2.5%, respectively. The levels of many macronutrients and micronutrients were tended to be significantly higher in AMF+ plants than in AMF- plants, supporting the association between AMF and enhanced growth of plants grown from AMF+ seedlings.

• Research in Plant Disease
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• v.10 no.1
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• pp.78-81
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• 2004

The resistance of 10 varieties of cucumber (Cucumis sativus L.) to powdery mildew, caused by Sphaerotheca fusca, was evaluated by a leaf disk assay. Leaf disks (10 mm in diameter) were removed from fully expanded leaves and then placed in petri dishes containing 0.16％ water agar amended with benzimidazole. Leaf disks were inoculated by dropping a 10 $\mu$l of conidia suspension. Conidiophore formation of powdery mildew was the greatest at $25^{\circ}C$. The response of the host to powdery mildew, based on the inoculation onto disks of the first leaf, highly correlated with results obtained from harvesting stage of cucumber plants in greenhouse test (r = 0.99$^{**}$). It is indicating that a leaf disk assay may precisely predict the response of cucumber plant to S. fusca.a.