• Korean Journal of Plant Resources
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• v.21 no.4
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• pp.260-264
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• 2008

For the resistance test for Phytophthora blight of $T_1$ and $T_2$ transformants in pepper, Phytophthora blight fungus was inoculated to seedlings of the $T_1$ and $T_2$ transformants by concentration (density: zoospore $10^3/ml$). Occurrence rate of blight at 5days after inoculation was 4.0 % in T1-1 line and 10.0% in $T_1-2$ line, and its rate for 12 days after inoculation was 52.0% in $T_1-1$ line, 64.0% in $T_1-2$ line, respectively. Therefore, the lower occurrence rate to blight was enable to select resistant transformants in the some inoculation density (zoospore $10^3/ml$), meanwhile 'Kumtap' and 'Subicho' were 100% in highest occurrence rate to blight. For field test, in which blight was commonly occurred, of the Youngyang Pepper Experiment Station, the acquired transformant resisting to blight was similar to characteristics of domestic varieties, 'Subic ho' for fruit shape, but there are some differences in growth, days to flowering, fruit characteristics. Occurrence of blight in $T_2-1-6$, and $T_2-4-9$ lines was smaller approxmately 30% than commercial varieties, 'Kumtap', although occurrence of blight in field was showed higher difference among tested lines. In this study, we concluded that the transformants showing blight resistance selected from habitual field could be fixed at every generation, and the developed transformation system was also considered to develop transformants in pepper.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.460-467
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• 2013

This study was conducted to reduce the using amount of chemical fungicides for the control of red-pepper Phytophthora blight. Effect of combination application of two microbial fungicides and two chemical fungicides for the control of red-pepper Phytophthora blight was examined in vitro, in greenhouse and under field conditions. Each microbial fungicides and chemical fungicides was two-fold diluted and mixed-soil drenched. In the greenhouse pot assay, the mixed application of B. pumilus QST2808 and a mixture of dimethomorph + ethaboxam (De) among four mixed applications of two microbial fungicides (B. pumilus QST2808, P. polymyxa AC-1) and two chemical fungicides showed the highest control effect against Phytophthora blight. Also, control effect of mixed application of B. pumilus QST2808 and De was similar to that of single application of De (dimethomorph + ethaboxam) or Mo (mancozeb + oxadixyl). In the field test, when the microbial fungicides (B. pumilus QST2808, P. polymyxa AC-1) and the chemical fungicide(De) for the control of Phytophthora blight of red pepper were mixed-soil drenched four times at 7~10 day-intervals, the control values were in the range of 78.8% to 82.0%. On the other hand when each of the two chemical fungicides (De, Mo) were soil drenched four times at 7~10 day-intervals, the control value were 65.7% to 85.8%. Consequently, the mixed application of the microbial fungicides and chemical fungicides could be recommended as a control method for reducing the using amount of chemical fungicides.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.41.1-41
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• 1999

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.195-198
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• 2011

To screen several promising red pepper cultivars, may be adaptable to organic cultivation conditions, seventy six F1 hybrids commercial and eight local purebred red pepper cultivars were tested. Comparing the infection rate of phytophthora blight between commercial (F1 hybrid) and local (Purebred) cultivars, average infection rate of commercial cultivars was 9.8% and that of local cultivars was 17.8%. But the infected fruits rate of anthracnose in field were similar as 3.3% in commercial (F1 hybrid) and 3.1% in local (Purebred) cultivars. In yield characteristics, average yield of commercial cultivars was 2.89 t $ha^{-1}$ and that of local cultivars was 2.22 t $ha^{-1}$. For organic pepper farmers it is more favourable to cultivation purebred cultivars because they can save to the same quality plant next year's crop. In this study among the local purebred cultivars, two cultivars are promising that their yield near to 3 t $ha^{-1}$ and have disease field resistance.

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.311-317
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• 2006

Using PCR amplification, we cloned a cellulase gene (ce/H) from the Bacillus subtilis AH18 which has plant growth-promoting activity and antagonistic ability against pepper blight caused by Phytophthora capsici. The 1.6 kb PCR fragment contained the full sequence of the cellulase gene and the 1,582 bp gene deduced a 508 amino acid sequence. Similarity search in protein database revealed that the cellulase of B. subtilis AH18 was more than 98% homologous in the amino acid sequence to those of several major Bacillus spp. The ce/H was expressed in E. coli under an IPTG inducible lac promoter on the vector, had apparent molecular weight of about 55 kDa upon CMC-SDS-PAGE analysis. Partially purified cellulase had not only cellulolytic activity toward carboxymethyl-cellulose (CMC) but also insoluble cellulose, such as Avicel and filter paper (Whatman No. 1). In addition, the cellulase could degrade a fungal cell wall of Phytophthora capsici. The optimum pH and temperature of the ce/H coded cellulase were determined to be pH 5.0 and $50^{\circ}C$. The enzyme activity was activated by $AgNO_3$ or $CoCl_2$. However its activity was Inhibited by $HgC1_2$. The enzyme activity was activated by hydroxy urea or sodium azide and inhibited by CDTA or EDTA. The results indicate that the cellulase gene, ce/H is an antifungal mechanism of B. subtilis AH18 against phytophthora blight disease in red-pepper.

• The Plant Pathology Journal
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• v.26 no.3
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• pp.280-285
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• 2010

In the course of a searching natural antifungal compounds from plant sources, we found that the methanol extract ($3,000\;{\mu}g/ml$) of Malus domestica fruits had potential of control against rice blast (Magnaporthe grisea) and tomato late blight (Phytophthora infestans). Under bioassay-guided purification, we isolated phloretin, a phenolic compound, with in vivo antifungal activity against M. grisea. By 1-day protective application of phloretin ($500\;{\mu}g/ml$), the compound strongly inhibited the disease development of M. grisea and P. infestans on rice and tomato seedlings, respectively. And red pepper anthracnose caused by Colletotrichum coccodes also was moderately suppressed. However, rice sheath blight (Rhizoctonia solani AG1), and barley powdery mildew (Blumeria graminis f. sp. hordei) were hardly controlled. In addition, the compound showed in vitro antifungal activity against some plant pathogenic fungi including Phytophthora capsici, Alternaria panax, Sclerotinia sclerotiorum, R. solani AG4, and M. grisea. This is the first report on the antifungal activity of phloretin against plant pathogenic fungi.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.121-126
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• 2000

Composition of fungal communities in three microhabitats such as soil, rhizosphere and rhizoplane were studied to understand the root environment of healthy and diseased plants in Phytophthora non-infested and infested fields, respectively. Samples were collected from the tomato- and red pepper-growing greenhouses in Kyungsang-Nam Province on April, 1999. Twenty-five species were isolated from each vegetation field using the dilution plate technique. There were a greater variety of species in infested fields than non-infested and in soils than in both rhizospheres and rhizoplanes. The number of species isolated were varied amongst the different microhabitats. A Trichoderma species was isolated only from non-infested fields.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.235-241
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• 2003

For the biological control of Phytophthora blight of red-pepper caused by Phytophthora capsici, an antibiotic-producing plant growth promoting rhizobacteria (PGPR) Bacillus sp. KL 39 was selected from a local soil of Kyongbuk, Korea. The strain KL 39 was identified as Bacillus megaterium by various cultural, biochemical test and API and Microlog system. B. megaterium KL 39 could produce the highest antifungal antibiotic after 40 h of incubation under the optimal medium which was 0.4% fructose, 0.3% yeast extract, and 5 mM KCl at 30 C with initial pH 8.0. The antifungal antibiotic KL 39 was purified by Diaion HP-20 column, silica gel column, Sephadex LH-20 column, and HPLC. Its RF value was confirmed 0.32 by thin-layer chromatography with Ethanol:Ammonia:Water = 8:1:1. The crude antibiotic KL39 was active against a broad range of plant pathogenic fungi, Rhizoctonia solani, Pyricularia oryzae, Monilinia fructicola, Botrytis cinenea, Alteranria kikuchiana, Fusarium oxysporum and Fusarium solani. The purified antifungal antibiotic KL39 had a powerful biocontrol activity against red-pepper phytophthora blight disease with in vivo pot test as well as the strain B. megaterium KL 39.

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.77-81
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• 1996

During the screening for the antifungal compounds against Phytophthora capsici causing phytophthora blight of red pepper, we isolated a strong active compound, bafilomycin $C_1$, produced by strain 3D3. The producing organism was identified as Streptomyces sp. based on taxonomic studies. The antifungal compound was purified from culture broth by HP-20 column chromatography, ethylacetate extraction, silica gel column chromatography and HPLC, and was identified as bafilomycin $C_1$ by color reaction, UV and $^{1}H$-NMR spectral data analysis. Bafilomycin $C_1$ showed strong antifungal activity against various phytopathogenic fungi.

• The Korean Journal of Mycology
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• v.19 no.3
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• pp.231-237
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• 1991

This study was conducted in order to find out biological control of sesame wilt and blight caused by Fusarium of oxysporum f. sp. vasinfectum and Phytophthora nicotianae var. parasitica by using Streptomyces spp. Two sesame pathogens, Fusarium oxysporum f. sp. vasinfectum and Phytophthora nicotianae var. parasitica were purely isolated from diseased sesame plants of the field. Streptomyces species were isolated from 72 soil samples collected from red pepper and sesame uplands in Chungbuk and selected as antagonists according to the results of dual culture. The selected Streptomyces isolates such as St-11 and St-20 were confirmed their antagonistic effect through mycelial inhibition zone and inhibitory effects on the mycelial growth of the pathogens by culture filterate of the antagonists. Inhibitory effects on the conidial germination of Fusarium oxysporum vasinfectum and Phytophthora nicotianae parasitica by the antagonists were also tested in addition to mycelial Iysis. The antagonists St-11 and St-20 showed inhibitory effect on growth of sesame seedlings after seeds soaked in the suspension. Effect of soil inoculation with antagonist St-11 showed 40 to 78 percent of control effect for two diseases in comparison with control under greenhouse.