• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.127-133
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• 2012

Inhibition effects on spore germination and mycelia growth for pepper anthracnose fungi (Collectricum acutatum) were investigated in vitro using eco-friendly agricultural materials as well as ecofriendly pesticides. The inhibition effect on mycelia growth of anthracnose fungi is the highest when the anthracnose mycelia were treated with a pesticide (commercial name: Koreayeok) that contains a mixture of Bacillus subtilis and Panibacillus polymyxa, resulting in 100% inhibition of the mycelia growth. Meanwhile, the range of 20~40% inhibition effects on the growth of anthracnose mycelia was observed with other commercial agricultural materials. The significant inhibition effects on spore formation of anthracnose fungus were shown in vitro with two water dispersible pesticides containing sulfur [BTB (100%) and SulfurStar (95.1%)], Koreayeok (95.0%), Borstar (99.0%) containing Bordeaux mixture, and Jihabudea-KM containing Psedomonas spp. (96.1%), respectively. Taken from these in vitro results of inhibiting of the spore germination and mycelia growth together, Koreayeok is the most effective on control of pepper anthracnose disease in vitro. In addition, two water dispersible pesticides containing sulfur (BTB and SulfurStar) and Borstar (99.0%) containing Bordeaux mixture are also significantly applicable to prevent pepper plants from anthracnose disease in vitro. It remains to be determined whether the selected eco-friendly agricultural materials in effective control of anthracnose in vitro can be used to control pepper anthracnose in field.

• Korean Journal of Organic Agriculture
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• v.29 no.4
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• pp.561-574
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• 2021

This study was conducted to evaluate the control efficacy of the organic farming materials (OFMs) on tuber rot of Gastrodia elata caused by Fusarium spp. The antifungal activities in vitro as well as the suppressive effect of 15 OFMs on the spore germination and germ tube growth by inoculating spore suspension on immature tubers in vivo were investigated. 7 OFMs inhibited the mycelial growth of Fusarium spp. and 7 of them were microbial agents. In the screening using immature tubers, 3 OFMs were very effective with control efficacy value of 70%. Among them, sulfur provided suppressive effect on both mycelial growth and spore germination against tuber rot of G. elata. Finally, 3 OFMs were selected to test the protective and curative effects, and all chosen OFMs significantly suppressed disease incidence when applied in the preventive action, in comparison with the curative action. Especially, sulfur and Bacillus subtilis gave excellent protective control efficacy with control values of 93.2% and 86.9%, respectively, whereas its curative control effect was relatively low (73.3%, 60.2%). On the other hand, the preventive and curative effects of citronella + paraffin oil + ethyl alcohol were 73.3% and 67.0%, respectively. This study suggests that tuber rot of G. elata can be controlled by some OFMs in the rain shelter greenhouse under continuous cultivation condition and protective treatment is more important and efficient.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.104.1-104
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• 2003

To screen for potential biocontrol agents against postharvest disease of garlics caused by Penicillium hirsutum, a total of 933 isolates (432 fungi and 501 bacteria) were isolated from the rhizoshere or rhizoplane of garlics. Among them, Pantoea agglomerans isolate 59-4 (Pa 59-4) was selected for a potential biocontrol agent by in vivo wounded garlic bulb assay, When the spore suspension (10$\^$5/ spores/$m\ell$) of Penicillium hirsutum was co-inoculated with spore or cell suspension of each fungal or bacterial isolate on wounded garlics, the isolate highly suppressed disease development. Soaking garlic bulbs in the suspension of Pa 59-4 significantly reduced garlic decay from p. hirsutum. However, Pa 59-4 did not inhibit the mycelial growth of P. hirsutum in dual-culture with P. hirsutum on Tryptic soy agar. In order to elucidate mode of action of Pa 59-4 nutrient competition between Pa 59-4 and P. hirsutum was investigated using tissue culture plates with cylinder inserts containing defusing membrane reported by Janisiewicz et al. The results showed that Pa 59-4 effectively suppressed spore germination and mycelial growth of blue mold in the low concentration (0.5％) of garlic juice, but did not suppress those of blue mold in the higher concentration (5％) of garlic juice. This result suggests that the mechanism in biocontrol of garlic blue mold by Pa 59-4 may involve in nutrient competition with P. hirsutum on garlic bulbs.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.336-342
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• 2009

To confirm the antimicobial mechanism of Torilis japonica, antimicrobial profile was observed on various spore conditions by combining 0.1% (3 mM) torilin with antimicrobial activity and 0.27% water fraction with germinants. A 75% ethanol extract of T. japonica fruit reduced Bacillus subtilis ATCC 6633 spore counts by 3 log cycles and reduced the vegetative cells to undetectable level (by about 6 log cycles) (both in terms of CFU/mL). Further fractionating the ethanol extract into n-hexane and water fractions revealed that the former reduced the spore count by 1 log cycle whereas the latter had no effect. The antimicrobial active compound was isolated and purified from the hexane layer, and identified as torilin ($C_{22}H_{32}O_5$). The water fraction of the ethanol layer did not show antimicrobial activity, whereas the antimicrobial effect of 0.1% (3 mM) torilin was significantly enhanced in the presence of the water fraction (0.27%). This result can be explained by synergistic effects of the water fraction containing considerable amounts of germinants such as L-alanine and K+ ions that triggered germination.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.453-458
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• 2011

BACKGROUND: Coleosporium plectranthi, an obligate parasite, which is responsible for the rust disease of Perilla frutescens, a plant in Korea, commonly known as Perilla. All rusts are obligate parasites, meaning that they require a living host to complete their life cycle. They generally do not kill the host plant but can severely reduce growth and yield. Food and feed spoilage fungi cause great economic losses worldwide. It is estimated that between 5 and 10% of the world food production is wasted due to fungal deterioration. Rust disease of Perilla is highly frequent and is widely spread in Korea. The present study was designed to investigate a novel media for the urediniospore germination in vitro and anti-rust activity as well as GC-MS analysis of oak pyroligneous liquor. METHOD AND RESULTS: Urediniospores were collected from the infected leaf of Perilla. Spore suspension was made and the suspension was inoculated in the 2% water agar media with proper humidity, then they were incubated at $26^{\circ}C$ for 56 hrs. The GC-MS analysis of the oak pyroligneous liquor was also done to check the chemical composition. GC-MS analysis of the wood vinegar was found 15 compounds, among them o-mthoxyphenol (25.93%), 2,6-dimethoxyphenol (16.06%), 4-methylenecyclohexanone (10.69%), 2,3-dihydroxytoluene (7.84%), levoglucosane (6.14%) and propanoic acid (5.32%) were the major components. Different concentration of the oak pyroligneous liquor was used, and spore inhibition was recorded on the basis of spore counting. The best results were noted at the concentration of 50% solution where 31.8% spores were inhibited. CONCLUSION: On the basis of the chemical composition of the oak pyroligneous liquor and the activity recorded we can use it as an anti-rust agent.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.480-489
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• 2017

We investigated a suitable method for in vitro germination of spores, propagation of prothalli, and the formation of sporophytes in the fern Dryopteris nipponensis Koidz. Spore germination rate was relatively high regardless of culture medium. Prothallus development was faster in Knop medium than in Murashige and Skoog (MS) media. Prothalli used in all experiments were obtained from germinated spores, and were cultivated in different concentrations of media components. The active formation of sexual organs such as antheridium made 1MS medium suitable for prothallus propagation, although there was a lower propagation ratio compared to Knop medium. Growth and morphogenesis of prothalli were most effective on 1MS medium containing 2% sucrose, and 60 mM of total nitrogen source with 20:40 mM ratio of $NH_4{^+}:NO_3{^-}$. To select a suitable soil composition for sporophyte formation, ground prothalli were cultivated on single and mixed soils using bed soil, peat moss, perlite, and decomposed granite for 14 weeks. Bed soil promoted sporophyte formation and growth regardless of single or mixed use. In particular, a mixture of bed soil and decomposed granite in a 2:1 ratio (v:v) led to accelerated sporophyte formation ($0.83/cm^2$).

• Research in Plant Disease
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• v.15 no.3
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• pp.209-216
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• 2009

During the period of June, 2005 to May, 2008, 44 host plants infected with powdery mildew were collected in the Jeon-ju and Jang-su districts of Jeonbuk province and in the Jang-sung district of Jeonnam province. The hyperparasites, Ampelomyces were confirmed in 12 plant species. Most of the pycnidium shapes of Ampelomyces were circular or oval shaped, and the sizes were different even within the same host plant, and also the color of pycnidium was ranged from light brown to dark brown. Ampelomyces species were isolated from 4 hosts including Impatiens balsamina L., Cucurbita pepo, Rudbeckia laciniata var. elatier and Youngia sonchifolia, and thus the most appropriate 12 Ampelomyces strains for the current experiment were selected. When analyzing the selected 12 strains' incubational and nutritional characteristics, the malt extract agar was the most appropriate media. When investigating the effect of osmotic pressure on the spore germination, 0.15M NaCl concentration was the optimum germination concentration. When the isolated Ampelomyces sp. was tested in-vitro, it was found to be effective to control in other plant pathogens, isolated Ampelomyces showed no pathogenicity to the plant. strains isolated . studied on rDNA ITS sequence analysis. The rDNA ITS sequence data of Ampelomyces sp. isolate BSLAH16 from Impatiens balsamina L. were analyzed and identified.

• The Korean Journal of Mycology
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• v.15 no.3
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• pp.149-157
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• 1987

This study was undertaken to investigate the differentiation, from spore germination to hyphae growth and phialide formation, of Aspergillus niger through the method of synchronous and submerged culture. Through continuous experiments by shake culture with potassium acetate medium, we observed the formation of spores at appropriate concentration and pH. Potassium acetate medium was set pH 5.5, 6.0, 6.5 and 7.0 on each scale, and control, 20 mM, and 40 mM, 80 mM and 160 mM concentrations on the other scale. Aspergillus niger was cultured in the defined media at $28^{\circ}C$, and mycelial dry weight, changes of pH and the onset of sporulation were checked. The mycelial dry weight, increased in potassium acetate medium, and pH increased during mycelial growth and gradually decreased after the spore formation. When pH increased excessively in Potassium acetate medium with pH 7.0, the mycelia could not adapt and mycelial dry weight decreased gradually. At pH 5.5, the onset of sporulation was done within one day at 20 mM it took, at 80 mM three days and at 160 mM concentration. in two days, at 40 mM one to four days were taken, 80 mM concentration respectively. At pH 6.5, the onset of sporulation was done in three days and four days at 80 mM concentrations respectively. Spore formation was not shown at pH 7.0. In controlled medium with all levels of pH, spore formation was not shown.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1158-1162
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• 2006

The glyoxylate cycle can conserve carbons and adequately supply tricarboxylic acid (TCA) cycle intermediates for biosynthesis when microorganisms grow on $C_{2}$ carbon sources. It has been reported that isocitrate lyase (ICL1), a key enzyme of the glyoxylate cycle, is highly induced when Magnaporthe grisea, the causal agent of rice blast, infects its host. Therefore, the glyoxylate cycle is considered as a new target for antifungal agents. A 1.6-kb DNA fragment encoding the ICL1 from M. grisea KJ201 was amplified by PCR, cloned into a vector providing His-tag at the N-terminus, expressed in Escherichia coli, and purified using Ni-NTA affinity chromatography. The molecular mass of the purified ICL1 was approximately 60 kDa, as determined by SDS-PAGE. The ICL1 inhibitory effects of TCA cycle intermediates and their analogs were investigated. Among them, 3-nitropropionate was found to be the strongest inhibitor with an $IC_{50}$ value of $11.0{\mu}g/ml$. 3-Nitropropionate inhibited the appressorium development in M. grisea at the ${\mu}M$ level, whereas conidia germination remained unaffected. This compound also inhibited the mycelial growth of the fungus on minimal medium containing acetate as a $C_{2}$ carbon source. These results suggest that ICL1 plays a crucial role in appressorium formation of M. grisea and is a new target for the control of phytopathogenic fungal infection.

• Journal of the Korean Wood Science and Technology
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• v.28 no.4
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• pp.10-16
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• 2000

Two wood decay ascomycetes fungi identified as Hypoxylon mammatum and H. truncatum were isolated from backyard of Korea Research Institute of Chemical Technology (KRICT) in Korea. Hypoxylon truncatum is newly recorded as a wood degrader in Korea. Unusual germination mechanisms of ascospores in H. mammatum and H. truncatum are described and illustrated. The differences between two species were noticed on the process of germ tube formation. In the process of germ tube formation, the fast movement to pigmented ascospores activated from their perispores was termed as spore eclosion that was only found in H. mammatum. This sophisticated recognition mechanism indicated the existence of specific eclosion and germ tube formation due to the composition of cell wall layers and their preferable host derive, based on examined two species under a genus. The observation on present study postulates different composition of wall layers of ascospore and different nutrient composition for germination.