• Applied Biological Chemistry
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• v.48 no.1
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• pp.82-88
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• 2005

3D QSAR studies for the fungicidal activities against resistive phytophthora blight (RPC; 95CC7303) and sensitive phytophthora blight (Phytopthora capsici) (SPC; 95CC7105) by a series of new 2-alkoxyphenyl-3-phenylthioisoindoline-1-one derivatives (X: A=propynyl & B=2-chloropropenyl) were studied using comparative molecular field analyses (CoMFA) methodology. The CoMFA models were generated from the two different alignment, atom based fit (AF) alignment and field fit (FF) alignment. The atom based alignment exhibited a higher statistical results than that of field fit alignment. The best models, A3 and A7 using combination fields of H-bond field, standard field, LUMO and HOMO molecular orbital field as additional descriptors were selected to improve the statistic of the present CoMFA models. The statistical results of the two models showed the best predictability of the fungicidal activities based on the cross-validated value $q^2\;(r^2_{cv.}=RPC:\;0.625\;&\;SPC:\;0.834)$, non cross-validated value $(r^2_{ncv.}=RPC:\;0.894\;&\;SPC:\;0.915)$ and PRESS value (RPC: 0.105 & SPC: 0.103), respectively. Based on the findings, the predictive ability and fitness of the model for SPC was better than that of the model for RPC. The fugicidal activities exhibited a strong correlation with steric $(66.8{\sim}82.8%)$, electrostatic $(10.3{\sim}4.6%)$ and molecular orbital field (SPC: HOMO, 12.6% and RPC: LUMO, 22.9%) factors of the molecules. The novel selective character for fungicidal activity between two fungi depend on the positive charge of ortho, meta-positions on the N-phenyl ring and size of hydrophilicity of a substituents on the S-phenyl ring.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.153-158
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• 1982

The study was conducted to obtain the basic information on the diseases epidemics of vegetable crops grown in Namji, Jinju, Gimhae and Suncheon under the extremely varied and specified conditions, plastic film house. The disease survey was conducted from the end of April, 1951 to April 1982. Leaf mold and late blight were serious foliar disease in tomato during the seedling stage, especially when the infected seeds were sown. The diseases increased rapidly 35 days after seeding. In both continuous cultivation of cucumber and rotation with upland crops, incidence of Fusarium wilt was severe while incidence of the disease was negligible in cultivations after paddy rice or grafting on pumpkin. Downy mildew of cucumber was severe in Jinju and Suncheon area, however, it was not so serious in Namji area where the growing season of cucumber was unfavorable for the maximum disease incidence. Cucumber mosaic virus disease was prevalent in the areas surveyed and the disease incidence was increased rapidly after June. Powdery mildew prevailed at the early stage of cucumber growth after transplanting in Namji area. Root rot and wilting caused by Phytophthora capsici was as the most destructive disease in pepper grown under the vinyl house, especially in Namji and Jinju area where the pepper has been cultivated intensively. The Phytophthora attacked most parts of young plants during the winter time and then induced crown rot on the adults plants. Cultivation of pepper in vinyl house was almost impossible because of the Phytophora disease by the end of June. Virus diseases to tomato plants were prevalent throughout the surveyed area and the damage was also severe. In Jinju and Gimhae area leaf mold and late blight showed high infection rate in tomato during the harvest time.

• The Plant Pathology Journal
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• v.29 no.1
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• pp.67-76
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• 2013

A chitinolytic bacterial strain having strong antifungal activity was isolated and identified as Burkholderia cepacia MPC-7 based on 16S rRNA gene analysis. MPC-7 solubilized insoluble phosphorous in hydroxyapatite agar media. It produced gluconic acid and 2-keto-gluconic acid related to the decrease in pH of broth culture. The antagonist produced benzoic acid (BA) and phenylacetic acid (PA). The authentic compounds, BA and PA, showed a broad spectrum of antimicrobial activity against yeast, several bacterial and fungal pathogens in vitro. To demonstrate the biocontrol efficiency of MPC-7 on late blight disease caused by Phyto-phthora capsici, pepper plants in pot trials were treated with modified medium only (M), M plus zoospore inoculation (MP), MPC-7 cultured broth (B) and B plus zoospore inoculation (BP). With the sudden increase in root mortality, plants in MP wilted as early as five days after pathogen inoculation. However, plant in BP did not show any symptom of wilting until five days. Root mortality in BP was markedly reduced for as much as 50%. Plants in B had higher dry weight, P concentration in root, and larger leaf area compared to those in M and MP. These results suggested that B. cepacia MPC-7 should be considered as a candidate for the biological fertilizer as well as antimicrobial agent for pepper plants.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.97.1-97
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• 2003

An antagonistic bacterium, KJ1R5,, to Phytophthora capsici was obtained from root interior of a healthy pepper plant. To identify the bacterial antagonist, 16S rDNA sequence analysis, Biolog system, fatty acid methyl-esters (FAMEs), and physiological and biochemical characterization were conducted. The determined 165 rDNA sequence of KJ1R5, showed higher similarities to those of a group consisting of several Chryseobacterium strains with 95.2, 95.2, and 95,1％ similarity to C. defluvii, Chryseobacterium sp. FR2, and C. scophthalmum, respectively, In addition, Halounella gailinarum, Bergeyella zoohelcum, and Riemerella anatipestifer are another group for KJ1R5, with 94.1, 89.7, and 87.2％ similarities, respectively When identification of the antagonistic bacterium, KJ1R5, was conducted using BIOLOG system, the strain KJ1R5, was identified as Flavobacterium tirrenicum (similarity； 0.75％). Fatty acid profiles of the strain KJ1R5, were composed mainly of iso-17：0 w9c and iso-15：0 and identified as Chryseobacterium balustinum (similarity 0.524％). KJ1R5, was Gram-negative, regular short rods ranging from 0.8 $\mu\textrm{m}$ to 1.0 $\mu\textrm{m}$ and had no flagella. Phenotypic characterization of the antagonistic bacterium indicated that KJ1R5, were included in the genus Chreseobacterium, which belongs to the family Flavobacteriaceae. The strain was distinguished from these six existing species. These results indicated that strain might be placed as a new species in the genus Chryseobacterium.

• Research in Plant Disease
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• v.18 no.2
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• pp.109-116
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• 2012

A bacterial strain antagonistic to some fungal phytopathogens was isolated from the stem of a Persimmon tree in Yeongam, Korea. This bacterium was identified as Bacillus subtilis by 16S rRNA gene sequencing and designated as B. subtilis GDYA-1. In in vivo experiment, the fermentation broth exhibited antifungal activities against Magnaporthe oryzae on rice plants, Phytophthora infestans on tomato plants, and Puccinia recondita on wheat plants. We isolated one antifungal compound and its chemical structure was determined by mass and $^1H$-NMR spectral data. The antifungal substance was identified as benzoic acid. It inhibited mycelial growth of M. oryzae, Rhizoctonia solani, Sclerotinia sclerotiorum, and P. capsici with minimum inhibition concentration (MIC) values, ranging from 62.5 to 125 ${\mu}g/ml$. Moreover, the substance effectively suppressed Phytophthora blight of red pepper caused by P. capsici in a pot experiment. To the author's knowledge, this is the first report on the antifungal activity of benzoic acid against phytopathogenic fungi. Benzoic acid and B. subtilis GDYA-1 may contribute to environmental-friendly protect crops from phytopathogenic fungi.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.23-28
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• 2007

Auxin-producing antagonistic bacterium K11, which can inhibit Phytophtora capsici, was isolated from a local red-pepper field soil in Gyeong-buk. In order to check for additional PGPR(plant growth promoting rhizobacterium) functions of the strain K11, we confirmed siderophore and cellulase productions by CAS (chrome azurol S) blue agar and CMC plate with congo red, respectively. The strain K11 was identified as Bacillus licheniformis with 98% similarity on 16s rDNA comparison and Biolog analyses. B. licheniformis K11 promoted mung bean adventitious root induction and enhanced root growth of mung bean (160%), pea (150%), and Chinese cabbage (130%), Also, B. licheniformis K11 was able to effectively suppress (63%) P. capsici causing red-pepper blight in the pot in vivo test. Therefore, we could select a triple-functional PGPR which has auxin, siderophore, and cellulase producing ability for effective crops production in organic farming.

• The Korean Journal of Pesticide Science
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• v.16 no.2
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• pp.178-186
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• 2012

This study was investigated for the purpose of the isolation and identification of antagonistic bacteria with antifungal activity against plant pathogens. This bacteria denominated Bacillus subtilis KYS-10 and the optimum growth condition were 4% sucrose, 1% yeast extract, 0.2% $K_2HPO_4$, pH 7, 150 rpm, $30^{\circ}C$, 8 day. The antifungal activities against nine plant pathogens determined inhibition zone size by diffusion methods. The results, G. zeae (scab) 70 mm and P. grisea KACC 40439 (blast), P. capsici KACC 40177 (phytophthora blight) and C. destructans KACC 41077 (root rot of ginseng) 40~43 mm, and C. gloeosporioides KACC 43520 (ripe rot), C. gloesporioides KACC 40003 (anthracnose), S. shiraiana KACC 41065 (stem rot) and S. shiraiana (mulberry sclerotial disease) 35~39 mm and F. Oxysporum KACC 44452 (bulb rot of ginseng) 28 mm. From these experiment results, author suggest that Bacillus subtilis KYS-10 would be developed as a biological control agent thorough the field experimet in the near future.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.140-146
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• 2012

The commercial product "pyto-patch" prepared as nano sized silver particle less than 5 nm, has effective antifungal activity against Collectotrichum gloeosporioides, Botrytis cinerea, Sclerotinia sclerotiorum in vitro. As a fungal growth inhibiton mechanism, it can reduce spore germination rate and mycelial growth. As s promising fungicide, Phyto-patch can control anthracnose effectively. The spore of C. gloeosporioides dipped in 5 ppm phyto-patch dilute suppressed germination rate to 13.2%, and mycelial growth stopped for 15 days at 10 ppm. The spore postinoculated on 10 ppm phyto-path smeared PDA surface could not germinate for 3 days and prohibit pathogen infection effectively. In field test, the anthracnose development of 4 ppm phyto-patch treated plot was less than 7% after 21 days compaired to 40% of it in untreated plot. In heavy rainfall season, pepper anthracnose effectivly contrrolled by regular 10 ppm phytopatch spraying every 7 days. The diseased pepper fruit decreased to 5.8% compaired to 94.6% in untreated plot. During drying period, the diseased pepper fruit havested in phyto-patch treated plot was 24.2%, but pepper fruit havested in untreated plot destroyed to 100% within 3 days. The nano silver particle coated on multching textile prevented late blight of pepper effectively and disease occurance delayed about month.