• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1999년도 정기총회 및 춘계 학술발표회
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• pp.43.3-43
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• 1999

• Journal of Ginseng Research
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• 제40권4호
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• pp.453-461
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• 2016

Background: This study aims to describe the characterization of Paenibacillus polymyxa GBR-1 (GBR-1) with respect to its positive and negative effects on plants. Methods: The morphological characteristics of GBR-1 were identified with microscopy, and subjected to Biolog analysis for identification. Bacterial population and media optimization were determined by a growth curve. The potential for GBR-1 as a growth promoting agent, to have antagonistic activity, and to have hydrolytic activity at different temperatures was assessed. The coinoculation of GBR-1 with other microorganisms and its pathogenicity on various stored plants, including ginseng, were assessed. Results: Colony morphology, endospore-bearing cells, and cell division of GBR-1 were identified by microscopy; identification was performed by utilizing the Biolog system, gas chromatography of fatty acid methyl esters (GC-FAME). GBR-1 showed the strongest antagonistic activity against fungal and bacterial pathogens. GBR-1 cell numbers were relatively higher when the cells were cultured in brain heart infusion (BHI) medium when compared with other media. Furthermore, the starch-hydrolytic activity was influenced by GBR-1 at higher temperature compared to low temperatures. GBR-1 was pathogenic to some of the storage plants. Coinoculation of GBR-1 with other pathogens causes differences in rotting on ginseng roots. A significant growth promotion was observed in tobacco seedlings treated with GBR-1 suspensions under in vitro conditions, suggesting that its volatile organic compounds (VOCs) might play a role in growth promotion. Conclusion: The results of this study indicate that GBR-1 has both positive and negative effects on ginseng root and other stored plants as a potential biocontrol agent and eliciting in vitro growth promotion.

• Mycobiology
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• 제42권2호
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• pp.158-166
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• 2014

In this study, bacterial strains were isolated from soils from 30 locations of Samcheok, Gangwon province. Of the isolated strains, seven showed potential plant growth promoting and antagonistic activities. Based on cultural and morphological characterization, and 16S rRNA gene sequencing, these strains were identified as Paenibacillus species. All seven strains produced ammonia, cellulase, hydrocyanic acid, indole-3-acetic acid, protease, phosphatase, and siderophores. They also inhibited the mycelial growth of Fusarium oxysporum f. sp. radicis-lycopersici in vitro. The seven Paenibacillus strains enhanced a range of growth parameters in tomato plants under greenhouse conditions, in comparison with non-inoculated control plants. Notably, treatment of tomato plants with one identified strain, P. polymyxa SC09-21, resulted in 80.0% suppression of fusarium crown and root rot under greenhouse conditions. The plant growth promoting and antifungal activity of P. polymyxa SC09-21 identified in this study highlight its potential suitability as a bioinoculant.

• 한국유기농업학회지
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• 제5권1호
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• pp.137-147
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• 1996

For the purpose of acquiring microbial agents that can be utilized to biologically control the major airborne diseases to apple trees, such as canker(Botryosphaeria dothidea), bitter rot(Glomerella cingulata), alternaria leaf spot(Alternaria mali), root rot(rosellinia necatrix), canker(Valsa ceratosperma) and gray mold rot(Botrytis cinerea), the effective microorgaisms were isolated, tested for antagonistic activity to the pathogens causing major diseases to apple trees and identifed. Screening of more than 5,000 species of microorganisms collected in nature for them antagonistic action to the pathogens causing 5 major diseases to apple trees resulted in selection of effective species. Out of the 11 species, one species designated as CAP134 demonstrated outstanding activity. The bacterial strain, CAP134 exerted antagonistic efficiency of 57% on an isolated strain and 40% on a donated strain of Botryosphaeria dothidea., 52% on an isolated strain and 46% on a purchased strain of Alternaria mali, 60% on Valsa ceratosperma 25% on Glomerella cingulata, and 64% Rosellinia necatrix. The CAP134 was identified as a bacterial strain to Bacillus subtilis ATCC 6633 based on morephology, culture conditions, and physio-biochemical characteristics.

• Journal of Ginseng Research
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• 제45권4호
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• pp.519-526
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• 2021

Background: This study aimed to investigate the effect of cold plasma treatment on the improvement of seed germination and surface sterilization of ginseng seeds. Methods: Dehisced ginseng (Panax ginseng) seeds were exposed to dielectric barrier discharge (DBD) plasma operated in argon (Ar) or an argon/oxygen mixture (Ar/O₂), and the resulting germination and surface sterilization were compared with those of an untreated control group. Bacterial and fungal detection assays were performed for plasma-treated ginseng seeds after serial dilution of surface-washed suspensions. The microbial colonies (fungi and bacteria) were classified according to their phenotypical morphologies and identified by molecular analysis. Furthermore, the effect of cold plasma treatment on the in vitro antifungal activity and suppression of Cylindrocarpon destructans in 4-year-old ginseng root discs was investigated. Results: Seeds treated with plasma in Ar or Ar/O₂ exhibited a higher germination rate (%) compared with the untreated controls. Furthermore, the plasma treatment exhibited bactericidal and fungicidal effects on the seed surface, and the latter effect was stronger than the former. In addition, plasma treatment exhibited in vitro antifungal activity against C. destructans and reduced the disease severity (%) of root rot in 4-year-old ginseng root discs. The results demonstrate the stimulatory effect of plasma treatment on seed germination, surface sterilization, and root rot disease suppression in ginseng. Conclusion: The results of this study indicate that the cold plasma treatment can suppress the microbial community on the seed surface root rot in ginseng.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.881-891
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• 2003

Paenibacillus polymyxa is a plant growth-promoting rhizobacterium (PGPR) which can be used for biological control of plant diseases. Several bacterial strains were isolated from rotten roots of Korean ginseng (Panax ginseng C. A. Meyer) that were in storage. These strains were identified as P. polymyxa, based on a RAPD analysis using a P. polymyxa-specific primer, cultural and physiological characteristics, an analysis utilizing the Biolog system, gas chromatography of fatty acid methyl esters (GC-FAME), and the 16S rDNA sequence analysis. These strains were found to cause the rot in stored ginseng roots. Twenty-six P. polymyxa strains, including twenty GBR strains, were phylogenetically classified into two groups according to the ERIC and BOX-PCR analyses and 16S rDNA sequencing, and the resulting groupings systematized to the degrees of virulence of each strain in causing root rot. In particular, highly virulent GBR strains clustered together, and this group may be considered as subspecies or biovar. The virulence of the strains seemed to be related to their starch hydrolysis enzyme activity, but not their cellulase or hemicellulase activity, since strains with reduced or no starch-hydrolytic activity showed little or no virulence. Artificial inoculation of the highly virulent strain GBR-1 onto the root surfaces of Korean ginseng resulted in small brown lesions which were sunken and confined to the outer portion of the root. Ginseng root discs inoculated in vitro or two-year-old roots grown in soil drenched with the inoculum developed significant rot only when the inoculum density was $10^{6}-10^{7}$ or more colony-forming units (CFU) per ml. These results suggest that P. polymyxa might induce ginseng root rot if their population levels are high. Based on these results, it is recommended that the concentration of P. polymyxa should be monitored, when it is used as a biocontrol agent of ginseng, especially in the treatment of stored roots.

• 생명과학회지
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• 제31권7호
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• pp.609-616
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• 2021

세균성 무름병 균[Pectobacterium carotovorum subsp. carotovorum (Pcc)]에 의해서 일어나는 무름병은 아시아 국가에서 재배되는 무에 있어서 심각한 질병 중의 하나로 알려져 있다. 이번 연구의 목적은 상업적으로 시판되는 무 품종의 세균성 무름병의 저항성에 대한 효율적인 생물검정법을 확립하고자 하였다. 첫째, 무 품종에 대해 세균성 무름병의 효율적인 생물검정 방법을 조사하였다. 6개의 무 품종을 다양한 조건[두 가지 온도(25℃와 30℃), 3가지 접종방법(관주, 분무, 침지), 두 발생단계(2와 4잎 단계)]으로 조사하였다. 연구 결과는 무름병균 1×10⁶ cfu/ml 농도를 분무한 4잎 단계와 30℃에서 배양한 생물검정 방법이 무 품종에 대해 가장 효율적인 방법임을 알 수 있었다. 둘째, 41개의 무 품종에 5가지 세균(KACC 10225, KACC 10343, KACC 10421, KACC 10458, KACC 13953)을 접종하여 저항성을 조사하였다. KACC 10421가 세균성 무름병의 감수성 및 저항성 질병 정도를 가장 잘 나타냈다. 41개의 무 품종 중 13개는 무름병 균에 대해 중도 저항성을 나타냈고 28개는 감수성을 나타냈다. 이 연구에서 중도저항성 무 품종은 세균성 무름병 저항성 육종을 위한 저항성 자원으로 활용 가능하고 육종가, 농민, 연구자, 최종 소비자에 의해서 다양한 목적을 위해 사용 가능할 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제18권9호
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• pp.1518-1521
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• 2008

Bacteria sense their population density and coordinate the expression of target genes, including virulence factors in Gram-negative bacteria, by the N-acylhomoserine lactones (AHLs)-dependent quorum sensing (QS) mechanism. In contrast, several soil bacteria are able to interfere with QS by enzymatic degradation of AHLs, referred to as quorum quenching. A potent AHL-degrading enzyme, AiiA, from Bacillus thuringiensis has been reported to effectively attenuate the virulence of bacteria by quorum quenching. However, little is known about the role of AiiA in B. thuringiensis itself. In the present study, an aiiA-defective mutant was generated to investigate the role of AHA in rhizosphere competence in the root system of pepper. The aiiA mutant showed no detectable AHL￢-egrading activity and was less effective for suppression of soft-rot symptom caused by Erwinia carotovora on the potato slice. On the pepper root, the survival rate of the aiiA mutant significantly decreased over time compared with that of wild type. Interestingly, viable cell count analysis revealed that the bacterial number and composition of E. carotovora were not different between treatments of wild type and the aiiA mutant. These results provide evidence that AHA can play an important role in rhizosphere competentce of B. thuringiensis and bacterial quorum quenching to Gram-negative bacteria without changing bacterial number or composition.

• The Plant Pathology Journal
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• 제23권3호
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• pp.174-179
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• 2007

Seedlot disinfection techniques to control mung bean sprout rot caused by Colletoricum acutatum and C. gloeosporioides were evaluated for commercial production scheme. Soaking seedlots in propolis (100 X) and ethanol (20% for 30 min) appeared promising with control values of 85.5 and 80.8 respectively, but still resulted in up to 20% rot incidence. None of the C. acutatum conidia survived through hot water immersion treatment (HWT) for 10 min at temperatures of 55, 60 and $65^{\circ}C$, whereas the effective range of the dry heat treatment (DHT) was $60-65^{\circ}C$. Tolerance of mung bean seedlot, as estimated by hypocotyl elongation and root growth, was lower for HWT than for DHT. Germination and growth of sprouts were excellent over the range of $55-65^{\circ}C\;at\;5^{\circ}C$ intervals, except for HWT at $65^{\circ}C$ for 5 min. At this marginal condition, heat damage appeared so that approximately 2% of seeds failed to sprout to normal germling and retarded sprouts were less than 5% with coarse wrinkled hypocotyls. These results suggested that DHT would be more feasible to disinfect mung bean seedlots for commercial sprout production. Heat treatment at above ranges was highly effective in eliminating the epiphytic bacterial strains associated with marketed sprout rot samples. HWT of seedlot at 55 and $60^{\circ}C$ for 5 min resulted in successful control of mung bean sprout rot incidence with marketable sprout quality. DHT at 60 and $65^{\circ}C$ for 30 min also gave good results through the small-scale sprouting system. Therefore, we optimized DHT scheme at 60 and $65^{\circ}C$ for 30 min, considering the practical value of seedlot disinfection with high precision and accuracy. This was further proved to be a feasible and reliable method against anthracnose incidence and those bacterial strains associated with marketed sprout rot samples as well, through factory scale mung bean sprout production system.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1999년도 정기총회 및 춘계 학술발표회
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• pp.47.1-47
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• 1999