인삼 뿌리썩음병균(Cylindrocarpon destructans)과 뿌리혹선충(Meloidogyne spp.)은 국내 인삼(panax ginseng C. A. Meyer) 연작장해의 주요인으로, 인삼 생산성 향상을 위해 방제가 필요하다. 본 연구는 새로 개발한 액제 훈증성 토양 소독제를 살포하며 동시에 비닐피복이 가능한 트랙터부착형 토양 소독기를 이용하여 dimethyl disulfide (DMDS)를 처리하였을 때, C. destructans와 뿌리혹선충의 방제효과를 분석하고, 시작기의 성능을 확인하기 위해 수행하였다. 토양 소독기를 이용하여 인삼 재배 포장에 DMDS를 처리한 후 비닐이 피복된 상태에서 5주간 훈증하였다. 토양 소독기의 성능은 약제 살포량 오차 2.5%, 작업능률 0.9h/10a로 40%의 노력절감 효과가 있는 것으로 나타났다. 또한, 처리 전후 C. destructans 의 밀도를 분석한결과 82.5%의 밀도 억제 효과가 있는 것으로 나타났으며, 뿌리혹선충 방제효과는 100%로 나타났다. 따라서, 본 토양 소독기 시작기를 이용하여 능률적으로 DMDS를 처리할 수 있으며, C. destructans와 뿌리혹선충의 방제효과를 볼 수 있는 것으로 판단된다.

인삼 근부병 억제토양 및 유발토양의 추출액 배지에서 병원균인 Fusarium solani, Rhizoctonia solani, Phytophthora cactorum, Sclerotinia sp.의 균계생장과 여기에 영향을 미지는 두 토양의 근권환경을 비교하였다. 4병원균 모두 추출액을 열처리하지 않았을 때 유발토양보다 억제토양 추출액 배지에서 생장이 더 억제되였고, 로 처리 하였을 때는 F. solani와 Sclerotinia sp.는 두 토양간에 차이가 없었으나 R. solani와 P. cactorum은 유발토양에서 균사생장이 더 좋았다. 또 억제토양 추출액의 열처리 온도를 높힐수록 모든 병원균의 생장이 증가되었다. 두 토양의 근권미생물 밀도는 Fusariumtn는 유의차가 없었으나 전세균, 진균은 모두 억제토양에 밀도가 더 높았으며 이 미생물들에 대한 Fusarium밀도의 비율도 억제토양이 더 높았다. 점토함량은 액제토양이, 모래함량은 유발토양이 각각 더 높았고, 화학성분중 Mg, Na 함량은 유발 토양이 더 많았으며 Ca, Fe, 도 유의성은 없었으나 억제토양 보다 높은 경향이었다.

인삼 근부병 억제토양 및 유발토양의 생물적, 이화학적 특성을 조사하였다. 병원균 Fusarium solani에 대한 길항균의 밀도가 근부병 유발토양에 비해 억제토양에서 훨씬 높았으며, 반대로 Fusarium spp.의 밀도는 더 낮았다. F solani의 후막포자 형성 및 균사생장도 근부병 억제토양에서 더 적었으며, 억제토양의 물추출액 속에서도 처리 4시간후 대형분생포자의 발아관이 길항미생물에 의해 분해되었다. 두 토양의 이화학적인 성질은 유의성있은 차가 없었으나 억제토양이 유발토양보다 점토함량이 조금 높은 경향이었다.

강원도 철원군 동송읍 일대의 인삼근부병을 조사한 결과 감자썩이선충(Ditylenchus destructor)을 분리 동정하였으며 이 선충이 인삼근부병의 한 원인임이 확인되었다. 이지역 인삼재식지 조사면적의 약 인 가 이 선충으로 인하여 피해를 입었다. 이 선충에 걸린 인삼은 주로 주근(Tap root)의 피층이 갈변하고 Sponge 화되며 피층내부에 Cork 조직이 발달하여 부리가 잘부러진다. 이런 뿌리는 표피가 잘 벗겨지고 심한경우에는 뿌리에 내공이 생기거나 뿌리전체가 썩어 없어지며 줄기와 잎은 급격히 푸른채로 시들어 죽는다. 잎이시드는 병징이 있는 포장에서는 감자썩이선충이 마리/30g 이었고 병징이 나타나지 않은 포장에서는 마리였다.

인삼 조사포닌과 인삼즙액이 인삼 근부패를 일으키는 병원균 Fusarium solani와 Erwinia carotovora의 생장과 증식 및 포자발아에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. 1. 인삼 조 Saponin의 농도가 증가됨에 따라 F. solani의 대형분생포자의 발아율은 억제 되었으며 500 ppm 이상 첨가시 현저하게 억제 되었다. 2. 토양 추출액은 초기에 F. solani의 포자 발아를 억제하는 효과가 있었으나 24시간후에는 무효화되었다. 3. 인삼 조 Saponin의 첨가 농도가 증가됨에 따라 F. solani의 포자형성량이 감소되었으며 고체배지에서 이러한 현상은 더욱 뚜렷하게 나타났다. 4. 인삼 Saponin을 첨가 했을시 균사생장량은 약간 감소되었으나 농도에 따른 감소율은 인정되지 않았다. 5. 인삼 조 사포닌은 농도가 증가 될 수록 F. solani의 Colony 형성을 억제하였으나 인삼즙액은 농도가 증가될수록 현저하게 F. solani의 Colony수를 증가시켰다. 6. 인삼 조 Saponin과 인삼즙액 모두 E. carotovora의 생장을 촉진시켰다.

인삼뿌리썩음병균, Cylindrocarpon destructans(Zins.) Scholten을 접종한 인삼절편으로 부터 얻은 섬유소분해효소 및 펙틴질분해광소의 역가는 그 농도, 시간에 비례하였다. Cellulase (Cx), endo-polygalacturonase(endo-PG), endo-poiymethylgalacturonase (endo-PMG), exo-polygalacturonase (exe-PG)와 exo-polymeth-ylgalacturonase(exo-PMG)의 역가는 접종후 4 일째 최대였으며 endo-PG와 endo-PMG는 1일 및 2일째는 전혀 검출되지 않았으나 exo-PG와 exo-PMG는 검출되었다. 접종후 6 일째에는 모든 펙틴질분해효소는 활성을 완전히 잃었으나 섬유소분해효소는 높은 역가을 유지하였다. Cx, endo-PG, endo-PMG, exo-PG 및 exo-PMG의 최적 pH는 각각 6.0, 5.5, 8.0, 7.0-7.5, 8.5이였다. Cx, endo-PG, endo-PMG, 및 exo-PG의 최적온도는 각각 exo-PMG 였다. 섬유소분해효소는 공시한 16개 이온중에서 0.05M 만이 억제하였다. 펙틴질분해효소는 이온에 따라 상이하였으나 과 이 가장 현저히 억제하였다. 공시한 8개 농약중에서 어느 것도 유효성분으로는 모든 효소작용을 억제하지 못했으며 exo-PG만은 모든 농약의 의하여 상당히 억제되었다. 그 중에서 Difolatan은 모든 펙틴질분해효소를 가장 잘 억제시켰다. 과 은 펙틴질분해효소를 거의 억제시켰으나 섬유소분해효소는 같은 농도에서 각각 에 이르렀다. Formalin은 exo-PG와 endo-PMG를 완전 억제시켰으나 다른 효소 특히 Cx는 그렇지 못했다. Difolatan은 모든 효소를 이상 억제하였으나 Cx는 그 이하였다. C. destructans가 분필하는 섬유소분해효소 및 펙틴질분해효소는 인삼뿌리썩음병과 밀접한 관계를 가지고 있으며 이 병을 효과적으로 방제하기 위하여 억제되어야 하겠다.

Ginseng (Pnanx ginseng C. A. Meyer) is famous worldwide, and is very important cash crop and medicinal herb in Korea. It takes four to five years to produce harvestable ginseng roots, and ginseng is attacked by several pathogens during cultivation. We investigated the disease rate caused by ginseng root rot from 6 years old ginseng cultivation fields (Chungnam; 9 fields, Chungbuk; 11 fields, Gangwon 5 fields). The highest disease severity was Dangjin D (2.9) and the lowest one was Gaesan C (0.6). Of the 625 isolations, 340 isolations were classified as Ilyonectria radicicola and Fusarium solani. Finally, genetic diversity of I. radicicola and F. solani was confirmed by sequence analysis. Among the I. radicicola group, I. mors-panacis, which is known as highly virulent pathogen, and I. liriodendri, I. robusta and I. cyclamicicola, which are weakly virulent pathogens, were identified. In the case of F. solani, it is divided into two groups, but it is necessary to conduct diversity research through genetic analysis and pathogenetic studies using various markers. Based on these results, it could be used as a basic data for control of ginseng root rot pathogens.

Background: Some phenolics detected in the soil may inhibit the seed germination and seedling growth of ginseng (Panax ginseng). This study investigated the effect of irrigation and ginseng root residue addition on the soil microbial community and root rot disease in 2-year-old ginseng. Methods and Results: Each 20 ℓ pot was filled with soil infected with ginseng root rot pathogens, and irrigated daily with 2 ℓ of water for one month. After the irrigation treatment, ginseng fine root powder was mixed with the irrigated soil at a rate of 20 g per pot. In descending order, NO3 −, electric conductivity (EC), exchangeable Na (Ex. Na) and K (Ex. K) decreased due to irrigation. In descending order, NO3 −, EC, Ex. K, and available P2O5 increased with the additon of ginseng powder to the soil. The abundance of Trichoderma crassum decreased with irrigation, but increased again with the incorporation of ginseng powder. The abundance of Haematonectria haematococca increased with irrigation, but decreased with the incorporation of ginseng powder. The abundance of Cylindrocarpon spp. and Fusarium spp., which cause ginseng root rot, increased with the incorporation of ginseng powder. The abundance of Arthrobacter oryzae and Streptomyces lavendulae increased with irrigation. The abundance of Streptomyces lavendulae decreased, and that of Arthrobacter spp. increased, with the incorporation of ginseng powder. Aerial growth of ginseng was promoted by irrigation, and ginseng root rot increased with the incorporation of ginseng powder. Conclusions: Ginseng root residues in the soil affected soil nutrients and microorganisms, and promoted ginseng root rot, but did not affect the aerial growth of ginseng.

Background : Plants cultivation is hindered by root rot, a major disease caused by the soil-born fungi. The ginseng-cultivated soil is one of the nutritious habitats for soil-borne microorganisms. Bacteria from ginseng-cultivated soil can increase plant growth by supplying nutrients and hormones as well as protecting against pathogenic fungal infections and induced systematic resistance. Methods and Results : The novel species DCY115T was isolated from ginseng-cultivated soil in Gochang province, Republic of Korea. The isolate was assigned to the genus Paraburkholderia due to its 16S rRNA gene sequence closely proximity to P. xenovorans LB400T (98.8%). Strain DCY115T is gram-negative, facultative aerobic, rod-shaped, non-flagellated, oxidase and catalase positive. The predominant isoprenoid quinone is ubiquinone Q-8. The genomic DNA G + C content is 61.3 mol%. Phenotypic tests and chemotaxonomic analysis place strain DCY115T in the genus Paraburkholderia. DNA-DNA hybridization values between strain DCY115T and closely related reference strains were lower than 51%. The DNA relatedness data in combination with phylogenetic and biochemical tests showed that strain DCY115T could not be assigned to any recognized species. Finally, strain DCY115T showed the plant growth promoting activities of siderophores production, phosphate solubilization, and antagonistic activity against root rot fungal pathogen Fusarium solani (KACC 44891T) and Cylindrocarpon destructans (KACC 44660T). Conclusion : The results support the novel strain DCY115T as a potential biocontrol agent against root rot fungal pathogen within the genus Paraburkholderia for which the name Paraburkholderia panacihumi is proposed. The type strain is DCY115T (= KCTC52952T = JCM32099T).

Background : Development of new real-time PCR diagnosis method for simultaneous diagnosis of Cylindrocarpon destructans and Fusarium solani, causative fungi of ginseng root rot disease. C. destructans and F. solani are known to be the major pathogens of ginseng root rot disease. Root rot caused by these pathogens is a disease that is difficult to control because the disease progresses slowly and it is difficult to diagnose early and even when symptoms of plant seeding are present, the disease is already spread in the roots. Diagnostic methods to detect the presence or absence of ginseng roots rot fungi in soil before ginseng cultivation are currently being used as a method for controlling. However, commercialized soil extraction kits and PCR diagnostics have cost, diagnostic time, and single diagnostic problems, and need to develop new diagnostic methods. Methods and Results : Primers and probes in the beta-tubulin 2 gene were designed for species-specific detection. In silico analysis, the detection rate of C. destructans was 100% and the detection rate of F. solani was 95%. The multiplex real time PCR optimization conditions including the internal control were established. The analytical sensitivity using positive samples was 10 copies/㎕ for C. destructans and 10 copies/㎕ for F. solani. As a result of performance comparison test with conventional PCR diagnosis methods, it was confirmed that the developed multiplex real time PCR method has the same or better performance in terms of sensitivity. In the developed soil extraction kit, the extraction time was reduced and the extracted DNA quality was improved, compared to the used soil extraction kit. Conclusion : From the above results, we expect that the developed C. destructans / F. solani multiplex real time PCR diagnosis method and soil extraction kit will be useful for real-time monitoring of ginseng root rot pathogenic fungi in the soil of ginseng cultivation area and diagnosis of suitability of ginseng cultivation area.

Background : Root rot is a major factors of replanting failure in ginseng cultivation. Some of the phenolics detected in the soil could inhibit the seed germination and seedling growth of ginseng. Methods and Results : Water of 2 ℓ was irrigated per pot (20 ℓ) into the soil infected with ginseng root rot pathogens for one month every day. After the irrigation treatment, the powder of ginseng fine root of 20 g per pot was mixed with the irrigated soil. NO3 -, electric conductivity (EC), exchangeable Na (Ex. Na) and K (Ex. K) were decreased in descending order by irrigation. NO3 -, EC, Ex. K, and available P2O5 were increased in descending order by incorporation of ginseng powder into soil. Trichoderma crassum was decreased by irrigation, but it was increased again by incorporation of powder. Haematonectria haematococca was increased by irrigation, but it was decreased by incorporation of powder. Cylindrocarpon spp. and Fusarium spp. causing ginseng root rot were increased by incorporation of powder. Arthrobacter oryzae and Streptomyces lavendulae were increased by irrigation. Streptomyces lavendulae was decreased, and Arthrobacter spp. was increased by incorporation of powder. Aerial growth of ginseng was promoted by irrigation, and ginseng root rot was increased by incorporation of powder. Conclusion : The residues of ginseng root in the soil affected soil nutrients and microorganisms, and promoted ginseng root rot, but did not affect the aerial growth of ginseng.

Background : Ginseng is an important agriculture plant in Korea. However, plant yield is reduced by pathogens. Cylindrocarpon destructans and Fusarium solani are responsible for root-rot and replant failure of ginseng in Korea. Because of root rot pathogen, the productivity decreased and repeated cultivation is difficult. Methods and Results : The number of Cylindrocarpon destructans and Fusarium solani in soils can be measured by real-time PCR. This methode makes it possible to select of land for caltivation of ginseng. The specific primers of C. destructans and F. solani were synthesized from β-tubulin region. The equation of the standard curve between the colony forming unit(cfu) and the Ct value in the C. destructans was y (Ct value) = -1.608X (cfu) + 39.325. The equation of the standard curve between the colony forming unit (cfu) and the Ct value in the Fusarium solani was y (Ct value) = -1.608X (cfu) + 39.077. This method makes possible to rapidly exactly measure the number of pathogens in soil. C. destructans, a ginseng root rot fungus, was detected in soil samples of 32 (16%) in soil samples. 35.5% of paddy field, 34.3% of paddy field, 64.1% of field, and 65.6% of paddy field were found in perennial plant. Conclusion : As a result, the major causative agent of ginseng root rot was Cylindrocarpon and the onset density was 102 cfu/g in soil. There was no significant difference in density between fusarium and disease.

Background : Ginseng root rot is a devastating disease caused by the fungus, Ilyonectria mors-panacis that generally attacks younger roots (-2 years), leading to defects in root quality, ginsenoside accumulation and also life cycle of the plant. Hence, there is an indispensable need to develop strategies resulting in tolerance against ginseng root rot. The protective role of silicon during pathogen infestation is well documented in other plant systems and a previous study demonstrated that silica nanoparticles are absorbed and accumulated more than the bulk silica in maize. However, the role of silica in ginseng-root rot pathosystem is unknown. Methods and Results : In the present study, we evaluated the effect of silica nanoparticles (N-SiO2) in Panax ginseng during I. mors-panacis infection. Long term analysis (30 dpi) revealed a striking 50% reduction in disease severity index upon 1 mM and 2 mM treatment of N-SiO2. However, N-SiO2 did not have any direct antifungal activity against I. mors-panacis. Candidate genes and metabolites based approach revealed jasmonic acid (JA) mediated sterol accumulation and incresed ginsenside biosyntesis as the key transcriptional reprogramming events orchestrated by N-SiO2 during the fungal infection. Conclusion : In a nut shell, N-SiO2 administration induces transcriptional reprogramming in ginseng roots, leading to increased phytosterol and ginsenosides synthesis resulting in enhanced tolerance against I. mors-panacis.

Background : Replant failure of ginseng is caused by soil-born pathogens causing root rot such as Cylindrocarpon destructans and Fusarium solani. Dazomet are widely used as soil fumigant to solve soilborne problems, and the degradation intermediates are toxic to nematodes, fungi, bacteria, insects and weeds. Methods and Results : The effects of cultivation of green manure crop, maize before and after soil fumigation on the control of ginseng root rot disease were compared using soil of field where 6-years-old ginseng was harvested. Fumigant (dazomet) were used for soil fumigation in May and September, respectively. Maize was grown for soil management before and after soil fumigation. Maize cultivation after May fumigation was delayed the sowing day by 15 days, and the fresh and dry weight decreased significantly. Maize cultivation after May fumigation increased pH but decreased EC, NO3, P2O5, and K significantly. Maize cultivation after May fumigation decreased fungi population and ratio of fungi and bacteria. Growth of 2-years-old ginseng was improved and the incidence of ginseng root rot was significantly decreased by maize cultivation after May fumigation. After harvesting 2-years-old ginseng, the population of Cylindrocarpon destructans was not different among treatments, but Fusarium solani showed a significant increase in September fumigation after maize cultivation. Conclusion : Maize cultivation after soil fumigation was effective in inhibiting ginseng root rot by improvement of mineral composition and microorganism in soils.

Background: The application of crop rotation systems may reduce the occurrence of soil-borne diseases by releasing allelochemicals and by subsequent microbial decomposition. Methods and Results: For reduction of ginseng root rot by the crop rotation system, after harvesting 6-year-old ginseng, fresh ginseng was grown along with continuous cultivation of sweet potato, peanut, and bellflower. Growth of 2-year-old ginseng was significantly inhibited in the continuous cultivation than in the first cultivation. Sweet potato, peanut and bellflower cultivations assisted in obtaining normal yields of ginseng in the first year after the harvest of 6-year-old ginseng. Salt concentration, potassium and sodium contents were gradually decreased, and, organic matter was gradually increased through cirp rotation. Phosphate, calcium and magnesium contents were not altered. The density of the root rot fungus was gradually decreased by the increase in crop rotation; however it was decreased distinctly in the first year compared to the second and third year. The severity of root rot disease tended to decrease gradually by the increase of crop rotation. Conclusions: Short-term crop rotation for three years promoted the growth of ginseng, however root rot infection was not inhibited significantly, although it was somewhat effective in lowering the density of the root rot pathogen.

Background : Ginseng (Panax ginseng C.A. Meyer) is one of the most important medicinal plants in Korea, but its yields are often reduced by a variety of root pathogens. The root rot of ginseng is a destructive soil-borne disease caused by Cylindrocarpon destructans (teleomorph: Ilyonectria radicicola). Methods and Results : Ilyonectria radicicola and its Cylindrocarpon-like anamorph represent a species complex that is commonly associated with root rot disease symptoms on virulence. During the course of this study, several species could be distinguished from I. radicicola sensu stricto based on morphological and culture characteristics. As results of investigated culture characteristics, optimal temperature for mycelial growth of isolates were 20℃, and colony pattern and color were slightly different on PDA. Isolates of I. radicicola were analyzed for their genetic relatedness based on several genes and microsatellite region. I. radicicola group was divided into two small groups. Conclusion : Therefore, we were able to confirm pathogenicity and genetic difference between the isolates in each of the groups of the pathogen. Among these isolates, 21.5% were classified as highly virulent and 78.5% were weakly virulent. *(Corresponding

Background : Korean ginseng is an important cash crop in Asian countries. However, plant yield is reduced by pathogens. Among the Ilyonectria radicicola-species complex, I. mors-panacis is responsible for root-rot and replant failure of ginseng in Asia. It is essential to find a way to reveal the existence of the pathogen before starting cultivation. Therefore, qRT-PCR method is developed to detect and quantify the pathogen in ginseng soils. Methods and Results : In this study, species specific Histone H3 primer set is developed for the quantification of I. mors-panacis. The primer set was applied on DNA of other microbes to evaluate its sensitivity and selectivity on I. mors-panacis DNA. Sterilized soil samples artificially infected by the pathogen in different concentrations were used to evaluate the ability of the primer set to detect the pathogen population in the soil DNA. Finally, the pathogen was quantified in many natural soil samples. The designed primer set was found to be sensitive and selective to I. mors-panacis DNA. In artificially infected sterilized soil samples, the estimated template using qRT-PCR was positively correlated with the pathogen concentration in soil samples (R2=0.94), disease severity index (R2=0.99), and colony forming unit (R2=0.87). In the natural soils, the pathogen was recorded in the most of fields produce bad yields with the range of 5.82 ± 2.35 to 892.34 ± 103.70 pg/g of soil. Conclusion : According to the presented results, the proposed primer set is applicable for estimating soils quality before ginseng cultivation. This will help in the disease management and crop protection in the future.