• Research in Plant Disease
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• v.14 no.1
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• pp.32-36
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• 2008

Bacterial wilt caused by Ralstonia solanacearum has become a severe problem on tomato in Korea and no effective control measures are available yet. Pseudomonas species play key roles for the biocontrol of many plant diseases especially in soil. A rhizobacterial population of 150 Pseudomonas strains, isolated from the rhizosphere soil of various plants grown at different sites, was screened for 2,4-diacetylphloroglucinol producing gene (PhlD) by PCR. Two strains (P83 and P84) among them were found to be phlD positive. When the isolates were analysed by 16S rDNA (Sensu Stricto), all isolates yielded amplified products of 1,018bp. Of the 150 isolates of Pseudomonas spp., a bacterial strain P. putida P84 isolated from tomato rhizosphere showed to suppress a wide range of phytopathogenic bacteria in vitro. The best source of carbon for P84 strain were glucose, arabinose, inositol and melibiose. In greenhouse experiments, P84 strain suppressed the development of bacterial wilt in tomato with a control value of 60%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.440-446
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• 2019

Pine wilt disease occurred for the first time in Busan in 1988 and the damage has since been increasing. In 2005, a special law was enacted for pine wilt disease by Korea Forest Service. Incidences relating to the forest pest had been frequent and chemical control as well as physical control techniques had been applied to control it. Therefore, there is a need to reduce the damage caused by the pine wilt disease through intensive management such as continuous monitoring, control, and monitoring based on active control as well as management measures. In this study, the UAV-based monitoring method was proposed as an economical way of monitoring the forest pest. The efficiency of the existing method and UAV method had been analyzed, and as a result the study suggested that UAV can be used for forest pest monitoring and indeed improve efficiency. The UAV-based forest pest monitoring method has a cost reduction of about 50% compared with the conventional method and will also help to reduce the area where the survey was omitted.

• Journal of Environmental Science International
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• v.28 no.3
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• pp.385-392
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• 2019

This study investigated the relationship among seven species of trichoderma through the identification of strains collected in Korea. The phylogenetic tree among the collected strains was classified into four groups. The trichoderma strains isolated in this way showed inhibitory effect on the fusarium wilt which is parasitic to cotyledon stem..The invisibility of J9, J10, J13 and J16 strains were higher in comparison with other strains in vitro test stand, and their spore production level was also higher. In the aluminum ring tests, it showed that the yield of the spores in J9, J10 and J13 were more than any other strain. As a result conducting the port test for cucumbers, the plant lengths of J13 were larger than the control plot, and the root lengths of all strains, except for J2 were longer than the control plot, and the root weights of J1, J9, J10, J13 and J16 were larger than the control plot. The disease severity for the fusarium wilt showed the smallest values at J13 and J16 in comparison with the control plot, and the control values of J13 and J16 were higher than other strains.

• The Plant Pathology Journal
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• v.38 no.4
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• pp.334-344
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• 2022

Bacterial wilt is a re-emerging disease on dry bean and can affect many other crop species within the Fabaceae. The causal agent, Curtobacterium flaccumfaciens pv. flaccumfaciens (CFF), is a small, Gram-positive, rod-shaped bacterium that is seed-transmitted. Infections in the host become systemic, leading to wilting and economic loss. Clean seed programs and bactericidal seed treatments are two critical management tools. This study characterizes the efficacies of five bactericidal chemicals against CFF. It was hypothesized that this bacterium was capable of forming biofilms, and that the cells within biofilms would be more tolerant to bactericidal treatments. The minimum biocide eradication concentration assay protocol was used to grow CFF biofilms, expose the biofilms to bactericides, and enumerate survivors compared to a non-treated control (water). Streptomycin and oxysilver bisulfate had EC95 values at the lowest concentrations and are likely the best candidates for seed treatment products for controlling seed-borne bacterial wilt of bean. The results showed that CFF formed biofilms during at least two phases of the bacterial wilt disease cycle, and the biofilms were much more difficult to eradicate than their planktonic counterparts. Overall, biofilm formation by CFF is an important part of the bacterial wilt disease cycle in dry edible bean and antibiofilm bactericides such as streptomycin and oxysilver bisulfate may be best suited for use in disease management.

• The Plant Pathology Journal
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• v.38 no.3
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• pp.239-247
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• 2022

Bacterial wilt caused by the pathogen Ralstonia solanacearum is a devastating disease of potato crops. Harmonizing immunity to pathogens and crop yield is a balance between productive, economic, and environmental interests. In this work, the agronomic performance of two events of potato cultivar INIA Iporá expressing the Arabidopsis thaliana EFR gene (Iporá EFR 3 and Iporá EFR 12) previously selected for their high resistance to bacterial wilt was evaluated under pathogen-free conditions. During two cultivation cycles, the evaluated phenotypic characteristics were emergence, beginning of flowering, vigor, growth, leaf morphology, yield, number and size of tubers, analyzed under biosecurity standards. The phenotypic characteristics evaluated did not show differences, except in the morphology of the leaf with a more globose appearance and a shortening of the rachis in the transformation events with respect to untransformed Iporá. The Iporá EFR 3 genotype showed a ~40% yield decrease in reference to untransformed Iporá in the two trials, while Iporá EFR 12 did not differ statistically from untransformed Iporá. Iporá EFR 12 shows performance stability in the absence of the pathogen, compared to the untransformed control, positioning it as an interesting candidate for regions where the presence of the pathogen is endemic and bacterial wilt has a high economic impact.

• The Plant Pathology Journal
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• v.39 no.5
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• pp.430-448
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• 2023

Recently, strategies for controlling Fusarium oxysporum f. sp. lycopersici (Fol), the causal agent of Fusarium wilt of tomato, focus on using effective biocontrol agents. In this study, an analysis of the biocontrol and plant growth promoting (PGP) attributes of 11 isolates of loamy soil Bacillus spp. has been conducted. Among them, the isolates B.PNR1 and B.PNR2 inhibited the mycelial growth of Fol by inducing abnormal fungal cell wall structures and cell wall collapse. Moreover, broad-spectrum activity against four other plant pathogenic fungi, F. oxysporum f. sp. cubense race 1 (Foc), Sclerotium rolfsii, Colletotrichum musae, and C. gloeosporioides were noted for these isolates. These two Bacillus isolates produced indole acetic acid, phosphate solubilization enzymes, and amylolytic and cellulolytic enzymes. In the pot experiment, the culture filtrate from B.PNR1 showed greater inhibition of the fungal pathogens and significantly promoted the growth of tomato plants more than those of the other treatments. Isolate B.PNR1, the best biocontrol and PGP, was identified as Bacillus stercoris by its 16S rRNA gene sequence and whole genome sequencing analysis (WGS). The WGS, through genome mining, confirmed that the B.PNR1 genome contained genes/gene cluster of a nonribosomal peptide synthetase/polyketide synthase, such as fengycin, surfactin, bacillaene, subtilosin A, bacilysin, and bacillibactin, which are involved in antagonistic and PGP activities. Therefore, our finding demonstrates the effectiveness of B. stercoris strain B.PNR1 as an antagonist and for plant growth promotion, highlighting the use of this microorganism as a biocontrol agent against the Fusarium wilt pathogen and PGP abilities in tomatoes.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.313-319
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• 2006

Two hundred bacterial strains were isolated from the soil around healthy tomato plants in a polyvinyl house, where most of the other plants showed bacterial wilt symptoms. The strains were screened in vitro for their antibacterial activity. Among them, a strain, KPB3 showed strong bactericidal activity against bacterial wilt pathogen, Ralstonia solanacearum. The strain KPB3 was identified using physiological and biochemical tests, and 16S rRNA analyses. Based on these tests, the strain was found to be closer to genus Paenibacillus. To control the bacterial wilt caused by R. solanacearum, greenhouse experiments were conducted to determine the effectiveness of the Paenibacillus strain KPB3. Drench application of this strain ($4{\times}10^8$ CFU $mL^{-1}$) into the pots containing tomato plants, post-inoculated with the pathogen, R. solanacearum could drastically reduce the disease severity, compared to the non-treated plants. To evaluate effectiveness of this strain under field conditions, experiments were carried out in polyvinyl houses infested with R. solanacearum, during spring and autumn of the year 2006. It was observed that, during spring, bacterial wilt was more prevalent compared to the autumn. During spring, 50.9% disease incidences occurred in non-treated controls, while, Paenibacillus strain KPB3 treated plants showed 24.6% disease incidences. Similarly, during autumn, around 17.2% plants were infected with bacterial wilt in non- treated polyvinyl houses, compared to the Paenibacillus strain KPB3 treated plants, which showed 7.0% disease incidences. These results demonstrated that, Paenibacillus strain KPB3 is a potential biological control agent against bacterial wilt caused by R. solanacearum, effective under greenhouse as well as field conditions. This is the first report showing biocontrol of R. solanacearum using a Paenibacillus spp. under field conditions.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.283-287
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• 2007

Pine Wilt Disease (Bursaphelenchus Xylophilus) has been attacked since 1988, then it becomes very serious problem of the all over the country. Government has been invested a lot of money to prevent but it is hard to survey the damaged area and ineffectively control the process of prevention. Therefore, this study is focused on development of Pine Wilt Disease (Bursaphelenchus Xylophilus) Prevention System using GIS and GPS through constructiong database of digital map, satellite imagery and attribute data and development component for desktop PC, internet and mobile system to realtime data transmission between project manager and field worker. Especially, we developed the mobile system that can transmit field conditions in realtime using GPS, GIS and CCD camera, the telecommunication control server that transmit received field condition data to web connecting module and system manager, the web system for end user to notify prevention details, the control system lot manager to recognize filed conditions and to control field workers and the wireless telecommunication module to connect in realtime between field and control center.

• Animal cells and systems
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• v.14 no.1
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• pp.31-36
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• 2010

The pinewood nematode Bursaphelenchus xylophilus causes pine wilt disease and is a serious economic concern for the forest industry of South Korea. To achieve effective control with limited resources, it is necessary to clarify the transmission routes and mechanisms of dispersal of this organism. Highly polymorphic and easy-to-use molecular markers can be used for investigating this aspect. In this study, we evaluated the usefulness of amplified fragment length polymorphisms (AFLPs) for investigating the genetic variations of B. xylophilus and related individuals from China, Japan, and South Korea. The AFLP patterns obtained in our study were similar to the microsatellite patterns reported in a previous study; our AFLP patterns indicated high genetic variability and cryptic genetic structure, but did not indicate any peculiar geographic structure. Moreover, the genetic distances between individuals suggested that the Korean population was affected to a greater extent by the Chinese population than the Japanese population. Further, the gene flow among the related species appeared to be limited; however, there may be also the possibility of genetic introgression among species. These results confirm the usefulness of AFLPs for understanding the epidemiology of pine wilt disease, thereby contributing to the effective control of this disease.

• The Plant Pathology Journal
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• v.31 no.3
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• pp.252-258
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• 2015

This is the first study reporting the evaluation of transgenic lines of tomato harboring rice chitinase (RCG3) gene for resistance to two important fungal pathogens Fusarium oxysporum f. sp. lycopersici (Fol) causing fusarium wilt and Alternaria solani causing early blight (EB). In this study, three transgenic lines TL1, TL2 and TL3 of tomato Solanum lycopersicum Mill. cv. Riogrande genetically engineered with rice chitinase (RCG 3) gene and their R1 progeny was tested for resistance to Fol by root dip method and A. solani by detached leaf assay. All the R0 transgenic lines were highly resistant to these fungal pathogens compared to nontransgenic control plants. The pattern of segregation of three independent transformant for Fol and A. solani was also studied. Mendelian segregation was observed in transgenic lines 2 and 3 while it was not observed in transgenic line 1. It was concluded that introduction of chitinase gene in susceptible cultivar of tomato not only enhanced the resistance but was stably inherited in transgenic lines 2 and 3.