• Mycobiology
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• 제42권2호
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• pp.174-180
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• 2014

We analyzed the genetic diversity of Cylindrocarpon destructans isolates obtained from Korean ginseng (i.e., Panax ginseng) roots by performing virulence tests and nuclear ribosomal gene internal transcribed spacer (ITS) and mitochondrial small subunit (mt SSU) rDNA sequence analysis. The phylogenetic relationship analysis performed using ITS DNA sequences and isolates from other hosts helped confirm that all the Korean C. destructans isolates belonged to Nectria/Neonectria radicicola complex. The results of in vivo and ex vivo virulence tests showed that the C. destructans isolates could be divided into two groups according to their distinctive difference in virulence and the genetic diversity. The highly virulent Korean isolates in pathogenicity group II (PG II), together with foreign isolates from P. ginseng and P. quinquefolius, formed a single group. The weakly virulent isolates in pathogenicity group I, together with the foreign isolates from other host plants, formed another group and exhibited a greater genetic diversity than the isolates of PG II, as confirmed by the mt SSU rDNA sequence analysis. In addition, as the weakly virulent Korean isolates were genetically very similar to the foreign isolates from other hosts, they were likely to originate from hosts other than the ginseng plants.

• 한국토양비료학회지
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• 제33권4호
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• pp.253-260
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• 2000

Agrobacterium tumefaciens에 존재하는 Ti 플라스미드의 virulence(vir)유전자들은 상처난 식물세포에서 분비되는 페놀화합물에 의해서 발현이 유도된다. 본 연구에서는 3종류의 A. tumefaciens들을 대상으로 8종의 페놀화합물들 중에서 vir유전자의 발현에 영향을 미치는 페놀 화합물들의 종류와 이들 균주에서 발현되는 vir유전자의 활성을 조사하였다. A. tumefaciens MW102에 존재하는 vir유전자는 4-hydroxyacetophenone, phenol, catechol, resorcinol과 vanillin등 5종류의 페놀화합물들에 의해서 높게 발현된 반면, 다른 A. tumefaciens Mw105와 Mw108의 vir유전자들은 이들 페놀화합물들에 의해서 매우 낮게 발현되거나 또는 발현되지 않았다. 또한 A. tumefaciens Mw102는 A. tumefaciens Mw105와 Mw108의 vir유전자를 매우 높게 발현시키는 acetosyringene에 의해서는 매우 낮게 발현되었다. 따라서 vir유전자의 발현을 유도시키는 능력은 Ti 플라스미드들의 종류와 페놀화합물들의 종류에 따라서 서로 다르다는 결과를 얻었다. 결과적으로 vir유전자 유도능력의 차이는 vir A 유전자에서 발현되는 sensor단백질의 차이 때문일 것으로 사료된다.

• 한국약용작물학회지
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• 제26권4호
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• pp.302-307
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• 2018

Background: A soil-borne pathogenic fungus, Ilyonectria radicicola (Cylindrocarpon destructans) causes root rot on ginseng (Panax ginseng C. A. Meyer) and is known to attack many other plants. The Nectria/Neonectria radicicola complex has been renamed as the I. radicicola complex after analysis of its multi-gene relatedness and morphological characteristics. The fungi in this complex have been reclassified into 16 species under the genus Ilyonectria based on characteristics analysis Methods and Results: To obtain useful data from the Korean ginseng root rot, I. radicicola was isolated from the rhizosphere soils of the chestnut tree. They were identified through a pathogenicity test and a survey of the morphological features. The existence of I. radicicola in soil samples was confirmed by PCR detections using nested PCR with species-specific primer sets. These were subsequenctly isolated on semi-selective media from PCR-positive soils. Genetic analysis of the I. radicicola complex containing these pathogens was done by comparing the DNA sequences of the histone h3 region. These isolates originating from the rhizosphere soils of chestnut constituted a clade with other closely related species or I. radicicola isolates originating from ginseng or other host plants, respectively. Additionally, the pathogenicity tests to analyze the characteristics of these I. radicicola isolates revealed that they caused weakly virulent root rot on ginseng. Conclusions: This is the first study reporting that I. radicicola isolates from chestnut rhizosphere soils can attack ginseng plant in Korea. Thus, these results are expected to provide informations in the selection of suitable fields for ginseng cultivation.

• The Plant Pathology Journal
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• 제24권2호
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• pp.183-190
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• 2008

Plant-cell-wall-degrading enzymes (PCWDEs) of Pectobacterium carotovorum subsp. carotovorum are the key virulence factor in pathogenesis of soft rot disease of vegetables. The production of PCWDEs is controlled in a cell density dependent manner to avoid the premature production of PCWDEs and subsequent activation of plant defense. N-oxoacyl-homoserine lactone (OHL) is essential for quorum sensing in the soft rot pathogen and the expI gene is responsible for OHL production. The ExpI homolog isolated from P. carotovorum subsp. carotovorum SL940 had 94% identity with ExpI of E. carotovora subsp. carotovora scc3193 and 74% identity with Carl of E. carotovora subsp. atroseptica. The transgenic plants that express exp I uner the control of CaMV35S promoter were able to produce diffusible OHL. Transgenic plants producing OHL were very resistant to the infection of P. carotovorum subsp. carotovorum. Since the PR1 gene was strongly induced and NPR1 and NPR4 were induced weakly in transgenic plants compared to the wild type, salicylic acid-dependent pathways is likely involved in the resistance to the soft rot pathogen P. carotovorum subsp. carotovorum in ExpI transgenic plants.

• 한국균학회지
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• 제23권2호통권73호
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• pp.114-120
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• 1995

병든 고추에서 수집한 종자에서 Colletotrichum dematium, C. gloeosporioides 및 Glomerella cingulata 등이 습지법에 의해서 검출되었다. C. gloeosporioides는 공시된 종자시료에서 우점종이었으며 그 다음이 C. dematium, G. cingulata의 순이었다. 탄저병균의 종자내 감염부위를 조사한 결과, 종피, 배유 및 자엽에서 C. dematium, C. gloeosporioides 및 G. cingulata가 검출되었으며 3종의 탄저병균의 검출율은 종피에서 더 많았고 배유와 자엽에서는 적었다. C. dematium, C. gloeosporioides와 G. cingulata의 종자감염은 종자부패, 모잘록 및 모마름병을 일으켰다. 접종시험결과 C. gloeosporioides가 가장 병원성이 강하였다. C. dematium은 상처가 있을 때 약한 병원성을 나타냈으며 G. cingulata는 유상 또는 성숙과에 대해서 약한 병원성이 있었다. 탄저병에 대한 종자소독 결과 베노람 수화제와 지오람 수화제의 효과가 우수하였다.

• Journal of Ginseng Research
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• 제44권2호
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• pp.332-340
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• 2020

Background: The valuable medicinal plant Panax ginseng has high pharmaceutical efficacy because it produces ginsenosides. However, its yields decline because of a root-rot disease caused by Ilyonectria mors-panacis. Because species within Ilyonectria showed variable aggressiveness by altering ginsenoside concentrations in inoculated plants, we investigated how such infections might regulate the biosynthesis of ginsenosides and their related signaling molecules. Methods: Two-year-old ginseng seedlings were treated with I. mors-panacis and I. robusta. Roots from infected and pathogen-free plants were harvested at 4 and 16 days after inoculation. We then examined levels or/and expression of genes of ginsenosides, salicylic acid (SA), jasmonic acid (JA), and reactive oxygen species (ROS). We also checked the susceptibility of those pathogens to ROS. Results: Ginsenoside biosynthesis was significantly suppressed and increased in response to infection by I. mors-panacis and I. robusta, respectively. Regulation of JA was significantly higher in I. robusta-infected roots, while levels of SA and ROS were significantly higher in I. mors-panacis-infected roots. Catalase activity was significantly higher in I. robusta-infected roots followed in order by mock roots and those infected by I. mors-panacis. Moreover, I. mors-panacis was resistant to ROS compared with I. robusta. Conclusion: Infection by the weakly aggressive I. robusta led to the upregulation of ginsenoside production and biosynthesis, probably because only a low level of ROS was induced. In contrast, the more aggressive I. mors-panacis suppressed ginsenoside biosynthesis, probably because of higher ROS levels and subsequent induction of programmed cell death pathways. Furthermore, I. mors-panacis may have increased its virulence by resisting the cytotoxicity of ROS.

• 한국식물병리학회지
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• 제3권3호
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• pp.217-222
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• 1987

남부지방의 고추, 오이, 대추, 딸기, 수도 등에 발생한 모잘록병 이병주에서 분리한 9가지 Rhizoctonia solani 균주의 고추, 오이, 무, 대추에 대한 병원성을 조사한 결과를 요약하면 다음과 같다. AGI 균주는 공시한 모든 기주에 대해 강한 병원성이 있었고, AG2군 1형 균주는 무와 배추에 대해서는 강한 병원성을, 고추에 대해서는 묘령이 증가함에 다라 발병이 적어 중정도의 병원성이 있었으나, 오이에 대해서는 병원성이 매우 약한 경향이었다. AG2군 2형 균주는 고추를 제외한 나머지 작물에는 병원성이 없거나 약하였고, AG5 균주는 공시한 모든 기주에 대해 중정도의 병원성이 있었다. 각 균주의 병원성 정도는 균계융합군(AG)간에는 차이가 있었으나, 같은 균사융합군(AG)내에서는 큰 차이가 없었다. 즉, AG1은 공시한 모든 기주에 강한 병원성을 보였으며, AG2군 1형 균주는 오이에 대해서만 약한 정도의 병원성을, 다른 기주에 대해서는 강한 병원성을 나타내었다. 각 기주의 묘령별 발병율은 살균토나 비살균토에서 묘령이 많을수록 감소하는 경향을 보였으나, 오이 뿌리와 수도줄기에서 분리한 병원성이 강한 균주에 대해서 각 기주는 묘령에 따른 발병율의 차이가 없었다. 살균토와 비살균토에서 병원성을 비교하면 병원균이 분리된 기주 및 근록의 작물에 대해서는 비살균토보다 살균토에서 더 강한 병원성을 보였으나, 병원균이 분리된 작물과 원록의 작물에 대해서는 살균토보다 비살균토에서 더 강한 병원성을 보였는데, 전반적으로는 다른 토양전염성병과는 달리 살균토보다 비살균토에서 병원성이 더 강하였다.

• 한방안이비인후피부과학회지
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• 제10권1호
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• pp.209-246
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• 1997

In the literatual study on the Ecthyma, the results were as follows. 1. The pathogenic factors of Ecthyma is divided three parts. One is exogenous pathogenic factors which including the wind evil, wind heat and toxic material produced by wetness evil. Another is endogenous pathogenic factors which including the declination of kidney-yang, impairment of the liver and kidney, the lower classes of yin-fire, accumulation of wetness-heat in the spleen asthenia, impairment of the liver and kidney, wetness-heat of three yang, asthenic heat-syndrome of three yin. The other is pathogenic factors neither endogenous nor exogenous which including the food and living, uncontrol sexual excess, anxiety and angry, injury of skin, injury of insects and animals. 2. Five viscera which was concerned with Ecthyma are liver, spleen and kidney. 3. Frequent region of Ecthyma are S-36(足三里) and C-7(陰交). External Ecthyma was rose to wetness-heat of three yang channel that cured easily. Internal Ecthyma was rose to asthenic heat-syndrome of three yin channel that cured hardly. 4. In the frequency of prescription, the most numerous prescription is Bojungikgitang(補中益氣湯) and the next are Kyukgigo(隔紙膏) and Yukmijihwanghwan(六味地滉丸). 5. In the frequency of medicine, the most medicine is Calomelas(輕粉) which included Hydrargyrum(水銀) and the next are Olibanum(乳香) and Resina Commiphorae Myrrhae(沒藥) which regulating vital energy and pain control medicine used that in order to destroy insects and remove polson. 6. In classification of the medical action, medicine of clearing away summer-heat and heat evil and activating blood circulation to dissipate blood stasis used to be very busy which in order to remove the disorder of vital energy for virulent heat-evil. 7. In classification of four characters, the most part is warm medicine, the next are cold and cool medicine and there is a few that is hot medicine. 8. In classification of five tastes, the most numerous tastes are bitter and acrid, the next are sweet, salty and sour tastes. 9. In classification of virulence of medicine, the most part is non-toxic, the next are weakly and deadly poison. 10. In classification of channel distribution, the most is the medicine that belongs to liver channel, the next are the lung, spleen, stomach and kidney channel.