• The Plant Pathology Journal
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• v.23 no.2
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• pp.109-112
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• 2007

This study was to examine the efficacy of a root-dipping application of antagonistic bacterial strains for the control of Phytophthora blight of pepper caused by P. capcisi, and to evaluate their plant growth-promoting effects in the field in 2005 and 2006. The candidate antagonistic rhizobacterial strains CCR04, CCR80, GSE09, ISE13, and ISE14 were treated by dipping plant roots with bacterial suspensions prior to transplanting. The candidate rhizobacterial strains CCR04, CCR80, GSE09, and ISE14 significantly (P=0.05) reduced the disease incidence and the area under the disease progress curves when compared to buffer-treated controls in at least a year test. The metalaxy l(fungicide-treated control) resulted in one of the lowest disease incidences among the treatments in both years. Moreover, the strains CCR04, CCR80, GSE09, and ISE13 significantly (P=0.05) increased the fruit weights and/or numbers of peppers in at least a year test compared to the buffer-treated controls. These results suggest that the antagonistic rhizobacterial strains CCR04, CCR80, and GSE09 could be efficient biocontrol agents by controlling Phytophthora blight of pepper and promoting the plant growth when treated with root-dipping at transplanting.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.85-94
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• 2016

The purpose of this study was to characterize the coffee ground and its possibility to develop the antifungal activity. pH, EC, and Zn contents of the coffee ground from coffee shops were higher than those of commercial coffee ground, but there was no significant difference in $K_2O$, CaO, MgO, $Na_2O$, Mn contents. The antimicrobial activity of the water soluble extracts from the coffee shop and the commercial coffee ground were tested for six major plant pathogens, Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium oxysporum, Phytophthora capsici, Alternaria alternata, and Botrytis cinerea. The result showed that there was reliable antifungal activity against all of tested plant pathogenic fungi. The inhibition effects of coffee ground compost extract on the spore germination and zoospore formation were investigated. Water soluble extracts of the coffee ground compost mixture added with 10% sesame oil cake were significantly inhibited the growth of conidia germination of A. altanata and zoospore formation of P. capsici in vitro. For investigating the functional materials of coffee ground compost, it was measured the total polyphenolic compounds contents with 30 days interval during decomposing coffee ground for 90 days. The total polyphenolic content increased with decomposing periods, and it observed that the highest total polyphenolic content was $0.35{\pm}0.03mg\;GAE/g$ on the 90th day in the coffee ground compost added with 10% sesame oil cake.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.131-134
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• 2006

The in vitro anti-fungal activity of hydroxylated fatty acids obtained from microbial conversion by Psuedomonas aeruginosa PR3 using ricinoleic acid(RA), eicosadienoic acid(EDA) and conjugated linoleic acid(CLA) as substrates, was investigated. Bioconverted hydroxylated fatty acids showed different anti-fungal activities potentials against the range of phytopathogenic fungi such as Botrytis cinerea, Rhizoctonia solani, Fusarium oxysporum, Sclerotonia sclerotiorum, Colletotricum capsici, Fusarium solani and Phytophthora capsici. RA and EDA showed up to 50% fungal mycelial inhibition at the concentration of $5{\mu}l\;ml^{-1}$. RA, EDA and CLA also exhibited anti-fungal activities with minimum inhibitory concentration(MIC), ranging from 500 to $1000{\mu}g\;ml^{-1}$. Screening was also carried out using varied concentrations of bioconverted RA and EDA for determining the anti-fungal effect on the spore germination of different fungi. Bioconverted RA and EDA showed a considerable degree of spore germination inhibition.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.197-201
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• 1999

Antagonistic bacteria active against phytopathogenic fungi, Phytophthora capsici, Pythium ultimum, Rhizoctonia solani, Botrytis cinerea, and Fusarium oxysporum were isolated from greenhouse soils. An antifungal compound was extracted by ethyl acetate from acidified culture filtrate and purified through column chromatography and thin layer chromatography. Activity-guided bioassay was followed throughout the purification steps using Pythium ultimum as a test organism. The purified antifungal compound was identified as phenylacetic acid (PAA) based on the data obtained from IR, EI/MS, $^1H-NMR$, and $^{13}C-NMR$. Two different isolates, which had vast differences in differential characteristics except 16S rDNA sequence homology, produced the same compound, phenylacetic acid. $ED_{50}$ values of the phenylacetic acid against P. ultimum, P. capsici, R. solani, B. cinerea, and F. oxysporum were 45, 21, 318, 360, and 226 ppm, respectively.

• The Plant Pathology Journal
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• v.17 no.1
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• pp.52-56
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• 2001

This study was undertaken to separate and identify antifungla substances produced by Gilocladium virens G1, a biocontrol agent used for the control of plant diseases caused by Rhizoctonea solani. The culture of G. virens G1 effectively inhibited the growth of R. solani, Colletotrichum gloeosporioides, and Phytophthora capsici, but less that of Fusarium oxysporum. The n-hexane extract of the G. virens culture, which was used for the purification of responsible substances, strongly inhibited R. solani and C. gloeosporioides, but not P. capsici, although the n-butanol extract was effective on all of the pathogens tested. An antifungal substance was purified using the n-hexane extract by Silica gel column chromatography and HPLC. The substance was examined for purity by HPLC and for nature by UV spectrometry, which differed from known antibiotic compounds such as gliotoxin, viridin and gliovirin. The antifungal substance was very liphophilic based on its solvent-solubility and Rf values on TLC, and more inhibitory to C. gloeosporioides than other fungal pathogens tested.

• The Plant Pathology Journal
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• v.33 no.3
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• pp.264-275
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• 2017

The spent mushroom substrate (SMS) of Lentinula edodes that was derived from sawdust bag cultivation was used as materials for controlling Phytophthora blight disease of pepper. Water extract from SMS (WESMS) of L. edodes inhibited mycelial growth of Phytophthora capsici, suppressed Phytophthora blight disease of pepper seedlings by 65% and promoted growth of the plant over 30%. In high performance liquid chromatography (HPLC) analysis, oxalic acid was detected as the main organic acid compound in WESMS and inhibited the fungal mycelium at a minimum concentration of 200 mg/l. In quantitative real-time PCR, the transcriptional expression of CaBPR1 (PR protein 1), CaBGLU (${\beta}$-1,3-glucanase), CaPR-4 (PR protein 4), and CaPR-10 (PR protein 10) were significantly enhanced on WESMS and DL-${\beta}$-aminobutyric acid (BABA) treated pepper leaves. In addition, the salicylic acid content was also increased 4 to 6 folds in the WESMS and BABA treated pepper leaves compared to water treated leaf sample. These findings suggest that WESMS of L. edodes suppress Phytophthora blight disease of pepper through multiple effects including antifungal activity, plant growth promotion, and defense gene induction.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.452-457
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• 1998

Thirty-eight isolates of Phytophthora sp. caused rots on roots and basal stems were collected from five flowering plants from 1992 to 1997 at eight cultivation areas in Korea. All the isolates were identified as P. nicotianae based on following characteristics. The fungus produced markedly papillate, not caducous and ovoid to spherical sporangia, abundant chlamydospores, and small oospores with amphigynous antheridia only when paired with either A1 or A2 mating type. All isolates grew well at 35$^{\circ}C$ and showed distinct arachnoid colony patterns on CMA and PDA. Sizes of sporangia and chlamydospores of five representative isolates from each plant averaged 43-52$\times$30-38 ${\mu}{\textrm}{m}$ and 28 ~34 ${\mu}{\textrm}{m}$. Mating type of the isolates was either A1 or A2, and oogonia and oospores were measured as 28~31 ${\mu}{\textrm}{m}$ and 21~25 ${\mu}{\textrm}{m}$. PCR-RFLP analysis of rDNA of the five isolates resulted that restriction band patterns of the small subunit and ITS regions were identical to a perilla isolate of P. nicotianae, but distinct from P. cactorum and P. capsici. Cross inoculation tests showed that the five isolates had pathogenicity to lily, christmas cactus, anthurium, baby's breath and carnation with different degrees. However, each isolate showed stronger pathogenicity to its corresponding original host than others. Among five lily cultivars Georgia and Quririna were more susceptible than Napoli and others. This is first report of Phytophthora root and stem rot of lily, Christmas cactus, anthurium, baby's breath and monochoria in Korea.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.178-184
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• 2010

Four major diseases of chili pepper including two fungal diseases, anthracnose (Colletotrichum acutatum) and Phytophthora blight (Phytophthora capsici), and two bacterial diseases, bacterial wilt (Ralstonia solanacearum) and bacterial spot (Xanthomonas campestris pv. vesicatoria), were investigated under future climate-change condition treatments in growth chambers. Treatments with elevated $CO_2$ and temperature were maintained at $720ppm{\pm}20ppm$ $CO_2$ and $30^{\circ}C{\pm}0.5^{\circ}C$, whereas ambient conditions were maintained at $420ppm{\pm}20ppm$ $CO_2$ and $25^{\circ}C{\pm}0.5^{\circ}C$. Pepper seedlings or fruits were infected with each pathogen, and then the disease progress was evaluated in the growth chambers. According to paired t-test analyses, bacterial wilt and spot diseases significantly increased by 24% (p=0.008) and 25% (p=0.016), respectively, with elevated $CO_2$ and temperature conditions. On the other hand, neither Phytophthora blight (p=0.906) nor anthracnose (p=0.125) was statistically significant. The elevated $CO_2$ and temperature accelerated the progress of bacterial wilt by two days and bacterial spot by one day compared to the ambient treatment. Temperature regime studies of the diseases without changes in $CO_2$ confirmed that the accelerated bacterial disease progress was mainly due to the increased temperature rather than the elevated $CO_2$ conditions.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1164-1169
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• 2005

Characteristics of sophorolipid and rhamnolipid were evaluated as antifungal agents against plant pathogenic fungi. Eight percent of mycelial growth of plant pathogen (Phytophthora sp. and Pythium sp.) was inhibited by 200 mg/l of rhamnolipid or 500 mg/l of sophorolipid, and zoospore motility of Phytophthora sp. decreased by $90\%$ at 50 mg/l of rhamnolipid and $80\%$ at 100 mg/l of sophorolipid. The effective concentrations for zoospore lysis were two times higher than those of zoospore motility inhibition. The highest zoospore lysis was observed with Phytophthora capsici; $80\%$ lysis at 100 mg/I of di-rhamnolipid or lactonic sophorolipid, showing the dependency of structure on the lysis. In the pot test, the damping-off disease incidence ratio decreased to $42\%\;and\;33\%$ of control value at 2,000 mg/l sophorolipid and rhamnolipid, respectively. These results showed the potential of microbial glycolipid biosurfactants as an effective antifungal agent against damping-off plant pathogens.

• 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.