• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.871-877
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• 2010

This study was conducted to investigate the effects of host tree species, temperature and humidity on ex vitro for seed germination in endangered species of Loranthus tanakae. In addition, we compared seed shapes between Loranthus tanakae and Viscum album that we could have easily shown in ex vitro condition. Seeds were germinated after one week inoculation and followed to develop radicles. Seed germination rates of Loranthus tanakae were 80~95% in most of the experimental conditions. The highest rate of holdfast penetrated to host plants was 72% in Populus alba var. pyramidalis among 13 different species tested at $20^{\circ}C$. Also the rates of their penetration were 57% in Morus bombycis, 55% in Acer palmatum and 42% in Castanea crenata at $20^{\circ}C$. Seeds were germinated under condition without irrigation and followed to withered in 12 weeks later. Stages of seed germination of the Loranthus tanakae were followed by radicle induction, holdfast development, haustorium formation and penetration in order in total period of 14 weeks.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.8-16
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• 2012

The objective of this study was to identify bacterial antagonists of R. solani AG2-2 (IV) on zoysiagrass and to evaluate their antifungal activity in vitro and in vivo to select an antagonistic isolate. Antagonistic isolates that inhibit large patch disease caused by R. solani AG2-2 (IV) in zoysiagrass were selected from several soils, and their antagonistic activities were investigated in vitro and in vivo. Of 216 bacterial isolates, 67 inhibited several plant pathogenic fungi. The isolates that inhibited stem-segment colonization by R. solani AG2-2 (IV) in zoysiagrass were tested in a growth chamber. Eleven isolates were active as plant growth promoting isolates. Among them, five plant growth promoting isolates and their concentration dependent efficiency on zoysiagrass following inoculation with R. solani AG2-2 (IV) was evaluated. Isolate H33 was one of the potential antagonistic isolates, and it was further tested against various plant pathogens. H33 not only suppressed the disease caused by R. solani AG2-2 (IV) on zoysiagrass but also promoted leaf weight and leaf height of zoysiagrass under growth chamber and greenhouse conditions. The H33 isolate, which belongs to Streptomyces arenae, was identified through physiological, biochemical, and 16S rDNA studies. Further studies will investigate the cultural characterization of S. arenae H33 and isolation and identification of antifungal substance produced by S. arenae H33.

• The Korean Journal of Mycology
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• v.4 no.1
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• pp.53-58
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• 1976

This study was undertaken to investigate the direct effect of three different kinds of steroid to Trichophyton(T.) mentagrophytes growth in vitro. A loopful of T. mentagrophytes was inoculated into Sabouraud's media and Sabouraud's media containing various concentrations of dexamethasone (0.04%-0.00004%) prednisolone (0.25%-0.00025%), triamcinolone acetonide (0.2%-0.0002%), Sabouraud's media containing imidazole nitrate (econasole nitrate) 10 micro gm. per cc. of media, and Sabouraud's media containing econazole nitrate $10{\mu}g$ per cc. of media of various dexamethasone concentrations (0.04%-0.00004%). After inoculation they were left for two weeks at room temparature and the colony diameter were compared between Sabouraud's media and Sabouraud's media containing various concentrations, of three different steroids, Sabouraud's media containing econazole nitrate and Sabouraud's media containing econazole nitrate of various dexamethasone concentrations. For complementary study, hanging slide culture were done between Sabouraud's media and Sabouraud's media containing various dexamethasone concentrations to compare the degree of branching of hyphae and sporulation serially. The study results were as follows: 1. There is no significant difference in growth rate of T. mentcgrophytes between Sabouraud's media and Sabouraud's media containing various concentrations of three different steroids. 2. There is no significant difference in growth rate of T. metagrophytes between Sabouraud's media containing econazole nitrate 10 micro gm per cc. of media and Sabouraud's media containing econazole nitrate 10 micro gm per cc. of media of various dexamethasone concentrations. 3. In hanging slide culture, there is no significant difference in branching of hyphae and sporulation between Sabouraud's media and Sabouraud's media containing various dexamethasone concentrations.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.598-608
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• 2019

Endophytic fungi have received much attention as plant growth promoters as well as biological control agents against many plant pathogens. In this study, 30 endophytic fungal species, isolated from various plants in China, were evaluated using in vitro dual culture assay against Fusarium oxysporum f. sp. cucumerinum, causing wilt in cucumber. The results of the present study clearly showed that all the 30 endophytic fungal isolates were highly capable of inhibiting the mycelial colony growth of Fusarium oxysporum f. sp. cucumerinum with inhibition % over 66% as compared to control treatments. Among all of them, 5 isolates were highly effective such as, Penicillium sp., Guignardia mangiferae, Hypocrea sp., Neurospora sp., Eupenicillium javanicum, and Lasiodiplodia theobromae, respectively. The Penicillium sp. and Hypocrea sp. were highly effective as compared to other isolates. From in vitro results 10 best isolates were selected for greenhouse studies. The results of the greenhouse studies showed that among all of them 3 endophytic fungal isolates successfully suppressed wilt severity when co-inoculation with pathogen Fusarium. oxysporum f. sp. cucumerinum. The endophytic fungi also enhanced plant growth parameters of the host plants, the antagonistic fungal isolates increased over all plant height, aerial fresh, and dry weight as compared to control.

• Research in Plant Disease
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• v.24 no.1
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• pp.59-65
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• 2018

Pyraclostrobin is a broad-spectrum fungicide that inhibits mitochondrial respiration. However, it may also induce systemic resistance effective against bacterial and viral diseases. In this study, we evaluated whether pyraclostrobin enhanced resistance against the bacterial spot pathogen, Xanthomonas euvesicatora on pepper (Capsicum annuum). Although pyraclostrobin alone did not suppressed the in vitro growth of X. euvesicatoria, disease severity in pepper was significantly lower by 69% after treatments with pyraclostrobin alone. A combination of pyraclostrobin with streptomycin reduced disease by over 90% that of the control plants. The preventive control of the pyraclostrobin against bacterial spot was required application 1-3 days before pathogen inoculation. Our findings suggest that the fungicide pyraclostrobin can be used with a chemical pesticide to control bacterial leaf spot diseases in pepper.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.7-14
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• 1974

These experiments were conducted to learn the antibiosis of microfloral organisms in the casing soil to Mycogone perniciosa, and interactions between M. perniciosa and Agaricus bisporus. The results obtained were as follows: 1. In vitro tests, the development of M. perniciosa was suppressed from the unidentified microfloral organisms in the casing soil. All the infected sporophores of A. bisporus occurred within an area applied with spore suspension of M. perniciosa as spot treatment and no infected ones in the area around the spot treated under cropping conditions. 2. In vitro tests, although the antagonistic relationship between M. perniciosa and A. bisporus was somewhat different in varying the kind of media, A. bisporus ultimately overgrew the colony of M. perniciosa. When spore inoculation of M. perniciosa was applied on the surface of grain spawn of A. bisporus and the mid layer of casing soil under cropping conditions, no infected sporophores were produced, whereas the infected sporophores were only produced on casing soil inoculated on the surface of casing soil with spore suspension.

• The Plant Pathology Journal
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• v.33 no.6
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• pp.608-613
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• 2017

The full-length sequence of a new isolate of Apple chlorotic leaf spot virus (ACLSV) from Korea was divergent, but most closely related to the Japanese isolate A4, at 84% nucleotide identity. The full-length cDNA of the Korean isolate of ACLSV was cloned into a binary vector downstream of the bacteriophage T7 RNA promoter and the Cauliflower mosaic virus 35S promoter. Chenopodium quinoa was successfully infected using in vitro transcripts synthesized using the T7 promoter, detected at 20 days post inoculation (dpi), but did not produce obvious symptoms. Nicotiana occidentalis and C. quinoa were inoculated through agroinfiltration. At 32 dpi the infection rate was evaluated; no C. quinoa plants were infected by agroinfiltration, but infection of N. occidentalis was obtained.

• Korean Journal of Plant Resources
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• v.25 no.2
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• pp.225-231
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• 2012

To figure out optimum culturing condition for $in$ $vitro$ yam ($Dioscorea$ $opposita$ Thunb.) production, various media components and environmental controls were evaluated, effective temperature, light condition and timing of the liquid media replacement for multiplication of yam in liquid culture were determined in this study. There was no visible difference detected for $15^{\circ}C$ and $25^{\circ}C$ temperature conditions. At $25^{\circ}C$, continuous light condition was more effective compared to 16 hour light/ 8 hour dark condition. Effect of media replacement was tested, and approximately 5 more microtubers obtained and 70% of increase in weight was detected when media replacement was performed. Timing for media replacement was tested at 2, 4, 6, 8, and 10 weeks after initial culture for 12 weeks. Considering both number and weight of microtubers, replacement of media 6 weeks after initial culture was most effective. In terms of component of media, significant increase in weight of microtubers was observed in MS media containing sucrose $60g{\cdot}L^{-1}$. In summary, the most effective condition for $in$ $vitro$ propagation of chinese yam is replacing medium 6 weeks after initial inoculation with MS medium containing sucrose $60g{\cdot}L^{-1}$ in continuous light condition.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.309-317
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• 2016

The study was conducted to evaluate the effects of microbial culture supplements on ruminal fermentation and fermentative quality of Italian ryegrass silage (IRGS) both in vitro and in situ. Three species of microbes (Lactobacillus casei (LC), Bacillus subtilis (BS), and Saccharomyces cerevisiae (SC)) were used in this study. They were applied to IRGS at 30 days after silage manufacture. Various items were measured using in vitro and in situ incubation technique after each microbial supplement was inoculated into IRGS at $0.5{\times}10^4CFU/g$. In the first experiment, in vitro ruminal fermentation characteristics of IRGS were evaluated at 0, 12, 24, 48, and 72 hours after microbes were inoculated into IRGS. In the second experiment, in situ fermentation characteristics were investigated at 0, 1, 3, and 5 days after the inoculation of each microbial supplement. In vitro ruminal $NH_3-N$ content was significantly (p<0.05) increased in LC-, BS-, and SC-IRGS at 12 hrs post incubation compared to that in control IRGS. In vitro ruminal total VFA concentration and dry matter digestibility (DMD) of IRGS were not significantly difference among LC-, BS-, and SC-IRGS, although they were numerically increased in LC-IRGS than those of the other IRGS. In addition, this study evaluated the fermentation characteristics and in situ DMD of IRGS with the lapse of incubation time up to 5 days. Throughout the incubation times from 1 day to 5 days, the pH value was significantly (p<0.05) lower in BS-, LC-, and SC-IRGS than that in control IRGS. Lactate was significantly (p<0.05) higher, and significantly (p<0.05) butyrate was lower in LC-IRGS than that in other treatments at 0 day. It was higher (p<0.05) in control IRGS than that of BS-, LC-, and SC-IRGS at 1-5 days. In situ DMD tended to increase in BS-, LC-, and SC-IRGS compared to that in control IRGS. Especially, DMD was higher in SC-IRGS than that in other treatments at 0 day. It tended to be higher in LC-IRGS at all incubation time. Taken together, these results suggest that it might be useful to select a microorganism by considering the feeding time of IRGS to ruminants because organic acids and DMD of IRGS were affected by the incubation time of each microorganism with IRG silage, especially for L. casei decreased the content of acetate and butyrate in IRGS.

• The Plant Pathology Journal
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• v.38 no.4
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• pp.355-365
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• 2022

Erwinia amylovora and E. pyrifoliae are the causative agents of destructive diseases in both apple and pear trees viz. fire blight and black shoot blight, respectively. Since the introduction of fire blight in Korea in 2015, the occurrence of both pathogens has been independently reported. The co-incidence of these diseases is highly probable given the co-existence of their pathogenic bacteria in the same trees or orchards in a city/district. Hence, this study evaluated whether both diseases occurred in neighboring orchards and whether they occurred together in a single orchard. The competition and virulence of the two pathogens was compared using growth rates in vitro and in planta. Importantly, E amylovora showed significantly higher colony numbers than E. pyrifoliae when they were co-cultured in liquid media and co-inoculated into immature apple fruits and seedlings. In a comparison of the usage of major carbon sources, which are abundant in immature apple fruits and seedlings, E. amylovora also showed better growth rates than E. pyrifoliae. In virulence assays, including motility and a hypersensitive response (HR), E. amylovora demonstrated a larger diameter of travel from the inoculation site than E. pyrifoliae in both swarming and swimming motilities. E. amylovora elicited a HR in tobacco leaves when diluted from 1:1 to 1:16 but E. pyrifoliae does not elicit a HR when diluted at 1:16. Therefore, E. amylovora was concluded to have a greater competitive fitness than E. pyrifoliae.