• Korean Journal of Microbiology
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• v.12 no.2
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• pp.94-98
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• 1974

This study was conducted from April 1 to September 31, 1973. Ten strains of Fusarium spp. were isolated from the diseased ginseng in two local areas at Kangwha-Gun nad Kumsan-Gun in Korea. Among of them, 2 strains ($G_1$, $G_4$) did not have virulence to ginseng in reinoculation. Their cultural, morphological characteristic and hose virulence to pea seedling were examined. Taxonomical identification of 8 isolates followed by the method of Wollenweber, Snyder nad Toussoun, Booth, Matuo and Snyder. All of eight strains were identified as the Fusarium solani f.sp.pisi(Jones) Synd. et Hans.

• Mycobiology
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• v.49 no.2
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• pp.196-200
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• 2021

In May to July 2019, ovate-leaf atractylodes seedling and plant with Damping-off symptoms were observed in farmer field at Sangju and Mungyeong, Korea. Seven fungal isolates have been retrieved from diseased root tissue and identified as Rhizoctonia solani AG-5 based on morphological and molecular characteristics. To the best of our knowledge, this is the first report on damping-off of ovate-leaf atractylodes caused by R. solani AG-5 in South Korea.

• The Plant Pathology Journal
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• v.21 no.2
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• pp.132-136
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• 2005

Two groups of phytoplasma were identified in chrysanthemum(Dendranthema grandiflorum) cv. Chunkwang showing distinct symptoms. Isolate Ph-ch1 showed symptoms of dwarf, witches'-broom, rosette and root death. The other isolate, Ph-ch2, revealed symptoms of dwarf, yellowing, leaf cupping, vein clearing and root death. The presence of phytoplasma structures in chrysanthemum leaf tissue was confirmed by transmission electron microscopy. The 16S rRNA gene was amplified from isolates Ph-ch1 and Ph-ch2 by PCR and cloned, and the nucleotide sequences were determined. In RFLP analysis, isolate Ph-ch2 showed profiles identical to Ph-ch1, except with restriction enzymes HhaI and MseI. The sequence data showed that isolate Ph-ch1 was most closely related to the aster yellows (AY) phytoplasma, and isolate Ph-ch2 was more closely related to stolbur phytoplasma than to AY phytoplasma. This is the first reported observation of stolbur phytoplasma in chrysanthemum species.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.236-242
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• 2003

A culture-independent and -dependent survey of the bacterial community structure in the rhizosphere and soil samples from hot pepper plants was conducted using 16S rDNA clone library and FAME analyses. Out of the 78 clones sequenced, 56% belonged to Proteobacteria, 4% to high G+C Gram- positive group, 3% to Cytophyga-Flexibacter-Bacreroides, and 32% could not be grouped with any known taxonomic division. Among the 127 FAME isolates identified, 66% belonged to low G+C Gram-positive bacteria (Baciilus spp.) and 26% to high G+C Gram-positive bacteria. In a cluster analysis, the results for both methods were found to be strikingly dissimilar. The current study is the first comparative study of FAME and 165 rDNA clonal analyses performed on the same set of soil, rhizosphere soil, and root samples.

• Journal of Life Science
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• v.31 no.7
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• pp.641-653
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• 2021

The purpose of this study was to confirm the antifungal activity, plant growth-promoting activity, and mineral solubilizing activity of 18 types of bacteria isolated purely from rhizosphere soil. The potential of isolates of the genus Bacillus and Pseudomonas as biocontrol agents was confirmed through the antifungal activity of these isolates. This activity has been determined to be due to various hydrolytic enzymes on the cell wall of plant pathogenic fungi and the production of siderophores in isolates. In addition, most of the isolates have been found to have aminocyclopropane-1-carboxylate deaminase production activity, indole-3-acetic acid production activity, and nitrogen fixation activity. These characteristics are believed to have a positive effect on root development, growth, and the productivity of crops via a reduction in the concentration of ethylene under conditions of environmental stress, to which plants are commonly exposed. In addition, on testing for the solubilizing activity of the isolates for phosphoric acid, silicon, calcium carbonate, and zinc, some isolates were found to have mineral solubilizing activities. Inoculation of these isolates during plant growth is expected to assist plant growth by converting nutrients necessary for growth into usable forms that can be absorbed by plants. The 18 isolated strains can be used as biocontrol agents due to their antifungal activity, plant growthpromoting activity, and mineral solubilizing activity.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.542-551
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• 2017

Small phytochemicals have been successfully adopted as antibacterial chemotherapies and are being increasingly viewed as potential antibiofilm agents. Some of these molecules are known to repress biofilm and toxin production by certain bacterial and yeast pathogens, but information is lacking with regard to the genes allied with biofilm formation. The present study was performed to investigate the inhibitory effect of burdock root extract (BRE) and of chlorogenic acid (CGA; a component of BRE) on clinical isolates of Klebsiella pneumoniae. BRE and CGA exhibited significant antibiofilm activity against K. pneumoniae without inflicting any harm to its planktonic counterparts. In vitro assays supported the ${\beta}$-lactamase inhibitory effect of CGA and BRE while in silico docking showed that CGA bound strongly with the active sites of sulfhydryl-variable-1 ${\beta}$-lactamase. Furthermore, the mRNA transcript levels of two biofilm-associated genes (type 3 fimbriae mrkD and trehalose-6-phosphate hydrolase treC) were significantly downregulated in CGA- and BRE-treated samples. In addition, CGA inhibited biofilm formation by Escherichia coli and Candida albicans without affecting their planktonic cell growth. These findings show that BRE and its component CGA have potential use in antibiofilm strategies against persistent K. pneumoniae infections.

• The Korean Journal of Mycology
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• v.45 no.2
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• pp.132-138
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• 2017

To obtain useful data on root rot in Korean ginseng, we performed phylogenetic analysis and pathogenicity test for Cylindrocarpon destructans isolated from peony. Cylindrocarpon destructans isolates from peony were proven to cause ginseng root rot. The isolate KACC44663 was identified as Ilyonectria robusta under the new classification system, which belongs to the I. radicicola species complex. This is the first report of the pathogenic isolate, which was isolated from another host plant, but not ginseng, that can cause root rot disease on ginseng in Korea.

• Journal of Ginseng Research
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• v.19 no.2
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• pp.181-187
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• 1995

Cylindvocarpon destmtalns isolate CY-92-01, pathogen of root-rot of Panax ginseng showed t the maximum mycelial growth on the Czapek solution agar among the thirteen kinds of media. Five isolates (Isolate CY-92-01, CY-92-03, CY-92-07, CY-94-01, CY-94-02) of C. destructan from various growth stages of p. ginseng recovered from several geographical sites also showed maximum growth in the Czapek-Dox broth compared with potato dextrose broth and V-8 juice broth. Rapid growth rate was maintained until 12 days after inoculation on the Czapek-Dox broth and mycelial weight was somewhat constant until 20 days. After 30 days of incubation, the mycelial weight began to decrease. The fungal growth occurred from 5$^{\circ}C$ to $25^{\circ}C$ and optimum temperature for growth was 2$0^{\circ}C$. Mycelial weight orderly decreased at 15, 25, 10, and 5$^{\circ}C$. Quantitative measurement was impossible at 5$^{\circ}C$. No fungal growth was occurred at the temperature higher than 3$0^{\circ}C$. Growth was observed at all tested pH ranges from 2.8 to 8.0. Optimum pH for growth was 4.0~5.0 followed by pH 3.3~3.5 and 5.4~6.0. The least growth occurred at pH 2.8.

• The Plant Pathology Journal
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• v.35 no.1
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• pp.51-62
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• 2019

A great variable response was observed when PP-3 and PP-J encumbered with 116 populations of root knot nematode (RKN) at two different temperatures ($25{\pm}2^{\circ}C$ and $30{\pm}2^{\circ}C$) and concentrations ($10^4$ and $10^5$ spores/ml). The PCR reaction amplified intergenic region between cytochrome oxidase subunit II gene (COII) and large subunit of rRNA gene (lrRNA) of the mitochondrial genome of different RKN species. The primer C2F3 and 1108 identified M. incognita with the highest frequency (52.6%) followed by M. javanica (36.8%) and M. arenaria (10.5%). The sizes of PCR products were 1.7 kb for M. incognita and M. javanica populations while populations of M. arenaria produced 1.1 kb fragment. The digestion with Hinf I yielded three different fragment length patterns on 1.5 % agarose gel. From current research it is concluded that intra-Meloidogyne genetic variability exist in RKN populations which have better encumbrance with P. penetrans.

• Journal of Life Science
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• v.13 no.5
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• pp.582-589
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• 2003

The effect of useful rhizobacterium added in bed soil on the early growth promotion of red pepper plug seedlings was investigated. Total 540 colonies of rhizobacteria from 385 samples of eggplant family roots were isolated. Among these, 5 isolates were selected for antifungal activity against pathogenic fungi such as Alternaria solani, Botrytis cinerea, Fusarium oxysporium, Phytophthora capsici, and Sclerotia sclerotiorum. Of all the isolates, MJ-3 having the most pronounced growth-promoting ability for red pepper was finally selected and identified as Bacillus amyloliquefaciens through characterization of biochemical and bacteriological aspects and 16S rDNA sequence. The plant height, stem diameter, root length and fresh weight of red pepper plants which were grown with inoculation of B. amyloliquefaciens MJ-3 were higher than those without inoculation. Especially the root weight of the inoculated red pepper plant increased by 44.3%, the content of endogenous plant hormone (CA$_1$) being 0.556 ng/g (dry weight).