• 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.

• The Plant Pathology Journal
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• 제24권3호
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• pp.352-356
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• 2008

Root discs of 4-year-old ginseng, Panax ginseng C. A. Meyer, were inoculated with the higher($10^8$ colonyforming units(CFU)/ml) and lower($10^6\;or\;10^5$ CFU/ml) initial inoculum levels of a plant-growth promoting rhizobacterium(PGPR), Paenibacillus polymyxa GBR-1 to examine rot symptom development and bacterial population changes on the root discs. At the higher inoculum level, brown rot symptoms developed and expanded on the whole root discs in which the bacterial population increased continuously up to 4 days after inoculation. In light and electron microscopy, ginseng root cells on the inoculation sites were extensively decayed, which were characterized by dissolved cell walls and destructed cytoplasmic contents. However, no rot symptoms were developed and the bacterial population increased only during the initial two days of inoculation at the lower inoculum level($10^6$ CFU/ml) of P. polymyxa GBR-1. At the lower inoculum level($10^5$ CFU/ml), boundary layers with parallel periclinal cell divisions, structurally similar to wound periderm, were formed internal to the inoculation sites, beneath which the cells were intact containing numerous normal-looking starch granules and no disorganized cell organelles, suggesting that these structural features may be related to the suppression of symptom development, a histological defense mechanism.

• 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.

• 식물병연구
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• 제20권3호
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• pp.227-233
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• 2014

초산(acetic acid)과 젖산(lactic acid)의 혼합액(MX)의 심비디움 배양토에 오염된 소나무재선충(Bursaphelenchus xylophilus)의 방제효과를 조사하였다. 실내실험에서 초산과 혼합액은 5.0-1.0% (pH 2.6-4.2)에서 젖산은 5.0%에서만 100%가까운 살선충율을 나타내었고 이보다 낮은 농도(0.5-0.1%, pH 5.1-6.9)에서는 초산과 혼합액보다 젖산에서 살선충력이 유의적으로 낮아졌다. 대부분의 농도에서 혼합액의 살선충율이 초산과 젖산의 평균보다 유의적으로 높게 나타나 혼합액의 살선충력 상승효과가 있을 것으로 판단된다. 폿트실험에서 유기산 혼합액(0.5%, 0.25%), 살선충제(fosthiazate, 표준량, 배량) 및 길항세균(Paenibacillus polymyxa GBR-1) 배양 희석액($10^7CFU/ml$) 등의 처리에 의해 심비디움 배양토에서의 소나무재선충의 밀도가 처리간에는 유의적인 차이가 없이 무처리에 비해 유의적으로 감소하였다. 모든 처리에서 약해가 나타나지 않았고, 처리 후 시기별 pH와 2년생 심비디움의 생육에 무처리 대조구와 유의적인 차이가 나타나지 않았다. 이러한 결과와 이들 식용 유기산의 안전성과 가격을 종합하여 볼 때, 심비디움의 재배 관리 중 생육단계에 따라 이 유기산 혼합액의 지속적인 사용은 검역해충의 방제에 있어서 친환경적이고 실제적으로 유효한 하나의 방법일 것이다.