• 한국응용곤충학회지
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• 제32권3호
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• pp.330-337
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• 1993

벼멸구에 강한 병원성이 있는 Serratia marcescens, biotype A2a를 분리, 동정하였다. 벼 유묘에 분무한 후 성충-계절풍을 따라 비래하는 형태-을 공시하고 병원성을 조사하여 3~5일 만에 강한 살충력을 발견하였다. 따라서, 본 세균의 곤충병원성 관련 형질 탐색을 하기 위하여 Tn5로써 돌연변이를 시도한 후, Chitinase, Protease, DNase indicator media에서 돌연변이 계통을 분리하였다. 이들을 공시충에 병원성을 검정한 결과 Pro-Strain중에서 병원력이 현저히 떨어지는 현상을 관찰하였다. 공시충을 전자현미경(SEM, TEM)으로 관찰하여, abdomen의 전장부위와 표피사이에 다수의 세균이 증식하였음을 발견하였다. 곤충복부표피조직 중 cuticle층은 intact한 상태였다. 따라서, 이에 관련된 유전자를 분리하기 위해 genomic library 실험을 진행하고 있다.

• The Plant Pathology Journal
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• 제24권3호
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• pp.337-351
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• 2008

Host-pathogen interaction in rice bacterial blight pathosystem was analyzed for a better understanding of their relationship and recognition of stable pathogenicity among the populations of Xanthomonas oryzae pv. oryzae. A total number of 52 bacterial strains isolated from diseased leaf samples collected from 12 rice growing states and one Union Territory of India, were inoculated on 16 rice varieties, each possessing known genes for resistance. Analysis of variance revealed that the host genotypes(G) accounted for largest(78.4%) proportion of the total sum of squares(SS), followed by 16.5% due to the pathogen isolates(I) and 5.1% due to the $I{\times}G$ interactions. Application of the Additive Main effects and Multiplicative Interaction(AMMI) model revealed that the first two interaction principal component axes(IPCA) accounted for 66.8% and 21.5% of the interaction SS, respectively. The biplot generated using the isolate and genotypic scores of the first two IPCAs revealed groups of host genotypes and pathogen isolates falling into four sectors. A group of five isolates with high virulence, high absolute IPCA-1 scores, moderate IPCA-2 scores, low AMMI stability index '$D_i$' values and minimal deviations from additive main effects displayed in AMMI biplot as well as response plot, were identified as possessing stable pathogenicity across 16 host genotypes. The largest group of 27 isolates with low virulence, small IPCA-1 as well as IPCA-2 scores, low $D_i$ values and minimal deviations from additive main effect predictions, possessed stable pathogenicity for low virulence. The AMMI analysis and biplot display facilitated in a better understanding of the host-pathogen interaction, adaptability of pathogen isolates to specific host genotypes, identification of isolates showing stable pathogenicity and most discriminating host genotypes, which could be useful in location specific breeding programs aiming at deployment of resistant host genotypes in bacterial blight disease control strategies.

• 한국식물병리학회지
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• 제13권4호
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• pp.225-231
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• 1997

기주, 분리 연도 및 장소가 다른 Botryis cinerea 20개 균주를 이용하여 오이세포벽을 탄소원으로 첨가한 배지에서 배양한 뒤 병원성과 관련이 있는 것으로 알려진 polygalacturomase, Iaccase, $\beta$-glucosidase의 활성을 측정하고 병원성과의 상관관계를 조사하였다. 조사된 효소들의 활성과 병원성과의 상관관계는 상관계수가 모두 0.5 이하로 직접적인 연관성을 인정할 수 없었다. 그러나 Bovendamm 배지에서의 균사생장 정도의 병원성은 r=0.522(p=0.05)로 정의 상관관계를 보였다. 또한 병원성이 강한 3균주와 약한 3균주를 선발하여 각 기주의 세포벽을 첨가하여 배양 후 poly-galacturonase 활성정도를 비교하였으나 뚜렷한 경향을 찾을 수 없었다. Exo-PG 항체를 이용한 면역혈청 blotting 결과 병원성이 다른 거의 모든 균주가 66kDa 크기의 1 band를 보이는 유사한 효소 pattern을 보였다. 이상의 결과로 볼 때 측정된 이들 효소는 병원성과 관련된 일차적 요인이 아닐 것으로 생각한다.

• The Plant Pathology Journal
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• 제30권2호
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• pp.136-150
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• 2014

Although multiple transcription factors (TFs) have been characterized via mutagenesis to understand their roles in controlling pathogenicity and infection-related development in Magnaporthe oryzae, the causal agent of rice blast, if and how forkhead-box (FOX) TFs contribute to these processes remain to be characterized. Four putative FOX TF genes were identified in the genome of M. oryzae, and phylogenetic analysis suggested that two of them (MoFKH1 and MoHCM1) correspond to Ascomycota-specific members of the FOX TF family while the others (MoFOX1 and MoFOX2) are Pezizomycotina-specific members. Deletion of MoFKH1 (${\Delta}Mofkh1$) resulted in reduced mycelial growth and conidial germination, abnormal septation and stress response, and reduced virulence. Similarly, ${\Delta}Mohcm1$ exhibited reduced mycelial growth and conidial germination. Conidia of ${\Delta}Mofkh1$ and ${\Delta}Mohcm1$ were more sensitive to one or both of the cell cycle inhibitors hydroxyurea and benomyl, suggesting their role in cell cycle control. On the other hand, loss of MoFOX1 (${\Delta}Mofox1$) did not show any noticeable changes in development, pathogenicity, and stress response. Deletion of MoFOX2 was not successful even after repeated attempts. Taken together, these results suggested that MoFKH1 and MoHCM1 are important in fungal development and that MoFKH1 is further implicated in pathogenicity and stress response in M. oryzae.

• 한국균학회지
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• 제43권4호
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• pp.286-289
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• 2015

순활물기생체인 Plasmodiophora brassicae는 병원성 검정을 위해서 반드시 뿌리혹을 장기적으로 보관하는 것이 매우 중요하기 때문에 그동안 병원성을 유지하는 것이 관건이다. 특히 기존의 방법은 100년 이상 사용되어온 저장법으로 개선이 필요하여 그 효율적인 방법을 밝히고자 하였다. 이 결과 장기적으로 병원성의 저하를 최소화하며 장기간 뿌리혹을 저장할 수 있는 방법은 $-70^{\circ}C$ 냉동고에 보관하는 것으로 확인되었고, 저장 조건은 뿌리혹을 그대로 보관하거나 뿌리혹을 갈아 균질화한 후 여러 겹의 거즈에 거른 것이 6가지 저장조건 중에 가장 효과적인 저장법으로 밝혀졌다.

• Journal of Forest and Environmental Science
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• 제33권4호
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• pp.342-347
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• 2017

Since the first report of the oak wilt disease at 2004 in Korea, the disease distributed over Korean peninsula and are still giving severe damages. The management of oak wilt disease in Korea has mainly focused on the control of insect vector, Platypus koryoensis. Neverthless the effective method for evaluating the pathogenicity of the pathogen, Raffaelea quercus-mongolicae (Rqm), and for screening chemical or biological agents with strong inhibitory activity against the pathogen, is absolutely necessary, an reliable method is not available so far. This study was conducted to develop the effective method for evaluating the pathogenicity of Rqm in oak trees. The culture suspensions of Rqm were artificially injected to the saplings of Quercus acutissima by using ChemJet tree injector. Three months after treatments, the treated saplings were cut and dipped into 1% fuchsin acid solution. There were significant differences in non-conductive area (%), discoloration area (%) and vertical discoloration length between the pathogen-injected and distilled water-injected control treatments. These results indicated that the pathogen is the causal agent for the dysfunction of water conductive tissue, which will finally result in wilt symptom. Re-isolation of the pathogen and PCR detection using specific primers for the pathogen also confirmed the presence of Rqm in the sapwood chips of the pathogen-injected saplings. These observations would be greatly applied to other related researches for evaluating the pathogenicity of tree wilt pathogens and biocontrol efficacy of the selected antagonistic microorganisms, in case that the wilt symptom is not easily shown by artificial inoculation of the causal agent.

• 한국가금학회지
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• 제27권2호
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• pp.109-114
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• 2000

The objective of these experiments was to develop an attenuated thermostable Newcastle disease virus(NDV), CBP-1 strain isolated from infected pheasants. Safety, pathogenicity and protective effects against velogenic NDV were also investigated to evaluate if the attenuated NDV, CBP-1 strain could be a candidate for a new NDV vaccine strain. CBP-1 strain was passaged up to the 173 times by nine days old embryonated eggs and chicken embryo fibroblast(CEF) cell cultures. Its sensitivitly to lipid solvents and low pH, thermostability, mean death time(MDT), intracerebral pathogenicity index(ICPI) of one day old chicks and intravenous pathogenicity index(IVPI) of four weeks old chicks were examined. Safety, boosting and protective effects were tested by chicks mortality. CBP-1 NDV strain had significant thermostability at 56$\^{C}$ for 30 minutes. by hemagglutinin activity and egg infectivity test, but was not resistant to lipid solvent. It showed possibility to use as a feed or water vaccine because of the resistance to low pH. MDT, ICPI and IVPI of CBP-1 were attenuated from 51.5, 1.96, 2.60 to 112.4, 1.12, 1.45. These results implied that the 173rd passages in embryonated egg and CEF cell cultures induced a substantial attenuation of the pathogenicity of the parent virus, changing the virulence from velogenic to intermediate between mesogenic and lentogenic. After vaccination with CBP-1 at one day old by drinking water mortality was 17.5%. However, spray vaccination with B1 at one day old, CBP-1 at two weeks ild and challenge with velogenic Kyojeongwon strain at four weeks old showed 93.5% survival rate. Mortality of chicks, vaccination with 173rd passaged CBP-1 strain at one day old, two weeks old and challenge with Kyokeongwon strain at four weeks old, was 20.0%. The results of these studies indicated that partial attenuated CBP-1 strain tended to be a low safety for ND of broiler chicks and would need to be more successive attenuation.

• Parasites, Hosts and Diseases
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• 제54권1호
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• pp.71-74
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• 2016

Trichomonas vaginalis is a flagellate protozoan parasite and commonly infected the lower genital tract in women and men. Iron is a known nutrient for growth of various pathogens, and also reported to be involved in establishment of trichomoniasis. However, the exact mechanism was not clarified. In this study, the author investigated whether the 120 kDa protein of T. vaginalis may be involved in pathogenicity of trichomonads. Antibodies against 120 kDa protein of T. vaginalis, which was identified as pyruvate:ferredoxin oxidoreductase (PFOR) by peptide analysis of MALDI-TOF-MS, were prepared in rabbits. Pretreatment of T. vaginalis with anti-120 kDa Ab decreased the proliferation and adherence to vaginal epithelial cells (MS74) of T. vaginalis. Subcutaneous tissue abscess in anti-120 kDa Ab-treated T. vaginalis-injected mice was smaller in size than that of untreated T. vaginalis-infected mice. Collectively, the 120 kDa protein expressed by iron may be involved in proliferation, adhesion to host cells, and abscess formation, thereby may influence on the pathogenicity of T. vaginalis.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.134.2-135
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• 2003

The plant-pathogenic species S. scabies, S. acidiscabies, and S. turgidiscabies cause the scab disease of potato and produce the phytotoxins, thaxtomins. necl, a gene conferring a necrogenic phenotype, is involved in pathogenicity and physically linked to the thaxtomin A biosynthetic genes. Identification of the pathogenic strains of Streptomyces from soil was performed through the polymerase chain reaction by using specific pathogenicity primer sets derived from the necl gene sequences of Streptomyces smbies. The DNA was extracted from soil using a bead-beating machine and modifications of the FastPrep system. The DNA was suitable for direct use in the PCR. The PCR products showed the bands of approximately 460 bp. This methods can be very usuful in identifying species responsible for scab diseases and studying on the ecology of plant-pathogenic Streptomyces spp.

• The Plant Pathology Journal
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• 제17권5호
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• pp.311-314
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• 2001

Phytophthora root rot of lettuce, which has not been reported in Korea before, occurred severely in liquid hydroponic culture. The disease occurred in all seasons and was most severe in summer from June to August, showing over 90% infection rate in some farms. A total of 51 isolates collected from various farms were all identified as Phytophthora drechsleri. The fungus showed strong pathogenicity to lettuce and Chinese cabbage, moderate pathogenicity to cucurbits and tomato, and weak pathogenicity to pepper. However, the fungus was not pathogenic to other leafy vegetables namely: chicory, kale, endive, garland chrysanthemum, spinach beet, and perilla. Among 10 species of Phytophtora inoculated to lettuce, only P. drechsleri and P. cryptogea were found pathogenic.