• Microbiology and Biotechnology Letters
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• v.28 no.6
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• pp.334-340
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• 2000

In order to select multifunctional powerful antagonistic biocontrol agent against red-pepper rotting fungi Phytophthora capsici, we isolated an indigenous antagonistic bacterium which produces antifungal substances and siderophores from a local soil of Kyongju, Korea. The isolated strain was identified as Pseudomonas fluorescens biotype F. The antibiotic produced from P. fluorescens 2112 inhibited hyphae growth and the zoospore germination of Phytophthora capsici. The favorable carbon, nitrogen source and salts for the production of antibiotic from P. fluorescens 2112 were glycerol, beef extract and LiCi at 1.0%, 0.5% and 5 mM, respectively. And antagonistic activity of P. fluorescens 2112 was confirmed against P. capsici in vivo.

• Journal of Life Science
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• v.9 no.1
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• pp.1-7
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• 1999

To isolate of antagonistic bacteria to Phytophthora capsici, which cause Phytophthora blight in red pepper, 237 isolates of Pseudomonas spp. and 260 isolates of Bacillus spp. were screened in selective media from rhizosphere soils of red pepper at Kyongsan, Kyongju, Yongchon and Euisung in Kyongbuk. Among total 497 isolates, 8 isolates of Pseudomonas spp and 4 isolates of Bacillus spp. inhibited the mycelial growth of Phytophthora capsici above 50$\%$ . These antagonistic bacteria showed more inhibitory effect on TSA (tryptic soy agar) than V-8 juice agar. Four isolates, P0704, P1201, B1101 and B1901, showing the most prominent antagonistic activity were selected and identified as P. cepacia (P0704, P1201), B. polymyxa (B1101) and B. subtilis (B1901), respectively. Cell free filtrates of these isolates were shown to inhibit zoosporangia germination and mycelial growth of p. capsici indicating that these isolates turned out to be bacteria producing antifungal substances. As a result of antagonistic test to Phytophthora blight in green house p. cepacia (P0704) showed the highest antagonistic effect with 46.7$\%$ and the rest of them were in the range of 13.4$\%$ to 26.7$\%$ .

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.399-405
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• 1996

In the culture medium, the three antifungal fractions against P. capsici were separated by Sephadex G-25 column chromatography and Silica-gel chromatography. The substance A in white powder and the substance B in sticky oil were isolated by ethyl acetate : acetone mixture(7 : 3), and the substance C in yellow powder was isolated by chloroform : ethyl acetate mixture(95 : 5). The crude extract by ethyl acetate from the culture medium acidified to pH 2 was known to inhibit completely the growth of P. capsici at the level of $50mgkg^{-1}$. The substance A and B were known to be effective above the level of $5mgkg^{-1}$, and the substance C was effective above the level of $1mgkg^{-1}$. However, at the level of $20mgkg^{-1}$, the efficiency was in the order of A>C>B. It is apparent on a pot-experiment scale that the three substances effectively control Phytophthora blight of the red-pepper plant grown in the soil inoculated with P. capsici.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.394-401
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• 2013

Trichoderma harzianum is one of rhizosphere fungus usually lives near the plant root regions in the soil. T. harzianum plays an important role in plant growth promotion and increases disease resistance against various plant pathogens on crops. In this study, the strain T. harzianum MPA167 was isolated from the barley rhizosphere soil in Suwon, Korea. Among 183 isolates, the strain T. harzianum MPA167 was selected as promising strain in which based on hyperparasitical activity against Phytophthora capsici and estimated disease control activity against P. capsici in the greenhouse conditions. The strain T. harzianum MPA167 was identified using 23s rDNA internal transcribed spacer(ITS) region sequences. MPA167 treatment ($1{\times}10^6$ spores/ml) showed greater disease suppression against Phytophthora blight of red-pepper caused by P. capsici in greenhouse compared with the water-treated control. Volatiles derived from T. harzianum MPA167 elicit growth promotion of tobacco and Arabidopsis seedlings in I-plate assay. In addition, T. harzianum MPA167 strain was also found to be effective for the growth promotion and induction of systemic resistance on red-papper plant. These results suggest that MPA167 might be used as one of the potential biocontrol agents.

• Research in Plant Disease
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• v.16 no.2
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• pp.158-162
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• 2010

Four promising biocontrol agents against Phytophthora capsici were selected from 507 bacterial isolates collected from rhizosphere soils and roots of pepper plants. In vitro experiment, these four biocontrol agents inhibited mycelial growth, germination of cystospores, and formation of zoosporangia and zoospores of Phytophthora capsici. In the pot experiment, the four biocontrol agents showed control efficiency higher than 70%. In greenhouse experiment, the isolates G28-6 gave the control value of 79.4%. These four biocontrol agents successfully colonized in the population density beyond 105 cfu/g on roots of pepper in vitro. The isolates G28-6 was identified as Pseudomonas aurantiaca, based on its cultural, morphological, and biochemical characterization and 16S rRNA gene sequence analysis.

• Journal of Environmental Science International
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• v.23 no.9
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• pp.1601-1608
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• 2014

Plasma reactor was used for the inactivation of Phytophthora capsici which is phytophthora blight pathogen in aquiculture. Effects of first voltage, second voltage, air flow rate, pH, incubation water concentration were examined. At the low $1^{st}$ voltage, under 80 V, the lag phase was noticed within 30 sec, however, it was not shown over 100 V. The variation of optimum operation condition was not shown by the variation of microorganisms. However, the inactivation rate was different by the variation of species of microorganisms. The inactivation rate and efficiency were increased by the increase of $2^{nd}$ voltage. The highest initial inactivation rate was shown at pH 3 and the rate was decreased by the increase of pH. The inactivation rate increased by the increase of air flow rate, however, it was shown as similar at the rate of 4 L/min and 5 L/min. The inactivation rate was distinctly decreased at the three times concentration of incubation solution comparing at the distilled water and basic incubation solution.

• The Korean Journal of Mycology
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• v.41 no.2
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• pp.112-117
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• 2013

Phytophthora capsici is one of major limiting factors in production of pepper and other important crops worldwide by causing foliage blight and rot on fruit and root. Increased demand for the replacement of fungicides has led to searching a promising strategy to control the fungal diseases. To meet eco-friendly agriculture practice, we isolated microorganisms and assessed their beneficial effects on plant health and disease control efficacy. A total of 360 bacterial strains were isolated from rhizosphere soil of healthy pepper plants, and categorized to 5 representative isolates based on colony morphology. Among the 5 bacterial strains (GJ-1, GJ-4, GJ-5, GJ-11, GJ-12), three bacterial strains (GJ-1, GJ-11, GJ-12) presented antifungal activity against P. capsici in an fungal inhibition assay. In phosphate solubilization and siderophore production, the strain GJ-1 was more effective than others. The strain GJ-1 was identified as Bacillus sp. using 16S rDNA analysis. Bacillus sp. GJ-1 was also found to be effective in inhibiting other plant pathogenic fungi, including Rhizoctonia solani, Pythium ultimum and Fusarium solani. Therefore, the Bacillus sp. GJ-1 can serve as a biological control agent against fungal plant pathogens.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.422-428
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• 2014

Endophytic bacterial strains from root tissue of strawberry were screened for their efficacy in growth improvement and control of Phytophthora blight disease of chili pepper plant under greenhouse condition. Plants treated with the strain EP103, identified as Pseudomonas fluorescens, showed growth improvement in terms of fresh weight and root length compared to the untreated control and other endophytic strains. When challenged with Phytophthora capsici, there was significant reduction of disease in EP103 treated plants with an efficacy of 78.7%. There was no direct inhibition of the target pathogen by EP103 when tested under in vitro antibiosis assay. Analysis of differential expression of selected marker genes for induced systemic resistance (ISR) in plants treated with EP103 and challenged with P. capsici showed up-regulation of PR1 and PR10 pathogenesis-related (PR) proteins. PCR analysis showed that EP103 produced secondary metabolites such as pyoluteorin, pyrrolnitrin, hydrogen cyanide and orfamide A. This study indicated the potential of endophytic P. fluorescens strain EP103 as an efficient biocontrol agent against P. capsici in chili pepper plant.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.393-399
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• 1998

Enterobacter sp.B54 which shows antagonistic activity to Phytophthora capsici on potato dextrose agar was selected among 112 strains isolated from Korean soil. After Tn5 lac-induced mutants were obtained through Pl :: Tn5 lac mutagenesis, 2 mutants for loss of antibiosis and 1 mutant for increased antibiosis were screened by using in vitro fungal inhibition assay. When the 3 mutants affected in antibiosis were analyzed by southern hybridization with pRZ102 (ColEl :: Tn5) as a probe, its results suggest that Tn5 lac was randomly inserted into different chromosomal sites in these mutants.

• Journal of Mushroom
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• v.19 no.4
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• pp.272-278
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• 2021

Bacillus velezensis HKB-1 was isolated from the composted spent mushroom substrate of Lentinula edodes (LeCSMS) and inhibited mycelial growth of phytopathogenic fungal species, Phythhopthora capsici, Collectotrichum coccodes and Fusarium oxysporium by more than 70%. B. velezensis HKB-1 showed bacterial growth rate 10 to 100 times higher than that of other commercial bacterial media in water extract of LeCSMS supplemented with 1% molasses. The LeCSMS medium was effective in promoting the growth of pepper and controlling Phytophthora blight disease of pepper.