• Research in Plant Disease
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• v.22 no.3
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• pp.145-151
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• 2016

Chemical fungicides have reduced Fusarium head blight (FHB) severity. However, by the effects of fungicide residues, they can only be used up to 30 days before time of harvest. Therefore, the development of new biofungicides that are applicable until harvest is required. In order to select plant extracts having antifungal activity against Fusarium graminearum for the control of FHB, we investigated the inhibitory effects of 225 medicinal plant extracts on spore germination of F. graminearum. Of these plant extracts, the methanol extract of Cirsium japonicum (CJ) roots showed the strongest antifungal activity. Through solvent partitioning, repeated column chromatography, and spore germination bioassay, two chemicals were purified and then their chemical structures were identified as ciryneol C (CC) and 1-heptadecene-11,13-diyne-8,9,10-triol (HD-ol) which are polyacetylene substances. Two active compounds effectively inhibited the germination of F. graminearum macroconidia; HD-ol ($IC_{50}$ of $3.17{\mu}g/ml$) showed stronger spore germination inhibitory activity than that of CC ($IC_{50}$ of $28.14{\mu}g/ml$). In addition, the wettable powder type formulation of ethyl acetate extract of CJ roots suppressed the development of FHB in dose-dependent manner, with control values of 78.92% and 31.56% at 250- and 500-fold dilutions, respectively. Combining these findings suggest that the crude extract of CJ roots containing polyacetylene compounds could be used as botanical fungicide for the control of FHB.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.543-546
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• 2005

Optimized conditions for protoplast preparation and regeneration from young hyphae of Monascus ruber were established. Heat shock treatment of spores gave rapid and synchronized germination. Spores collected from cultures grown for 7-8 days at $30^{\circ}C$ were germinated until over 70% germ tubes reached to 3-5 spore length. Enzymatic digestion of young hyphae was optimal with 50 mg/mL Glucanex in 0.1 M sodium citrate buffer containing 0.8 M mannitol as an osmotic stabilizer. Regeneration rate was around 10% when 0.8 M sorbitol was used as an osmotic stabilizer in regeneration medium. These conditions will be applied in genetic study of M. ruber that produces citrinin at high level and thus is good model strain for molecular genetic dissection of citrinin biosynthesis.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.309-310
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• 2005

Bioconverted linolenic acid (bLNA) obtained from linolenic acid by Pseudomonas aeruginosa PR3, showed anti-fungal activity against plant pathogens such as B. cinerea, F. oxysporum, F. solani, P. capsici and C. capsici. The oil sample also showed anti-fungal activity with MIC values, ranging from >250 to >1,000 ${\mu}g/ml$. Varied concentrations of bLNA had a great potential effect on spore germination of different fungi.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.261-267
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• 1996

To examine the potential utilization of chitosan, the biodegradable natural polymer, as a control agent of apple white rot caused by Botryosphaeria dothidea in a new control measure by coating it on the diseased branches, the various antifungal activities of chitosan was investigated. Chitosan showed significant inhibitory effect on the mycelial growth of B. dothidea, along with the morphological changes including hyphal swelling and ultrastructural changes on solid PDA medium. In liquid PD broth medium, the chitosan showed more significant effect on the growth of B. dothidea also forming cell clusters indicating affection on the hyphal extension. The growth of B. dothidea was inhibited more than 90% at the concentration of 1.0 mg/ml. Chitosan also detained the spore germination and induced the morphological change of germ tubes. Glucosamine, monomer of chitosan, did not affect on the growth of B. dothidea indicating the antifungal activity was caused by chitosan polymer.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1997.06a
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• pp.47-55
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• 1997

Plant growth promoting fungi(PGPF) obtained from zoysiagrass rhizosphere offer dual advantages - induse systemic disease resistance response in cucumber to C. orbiculare infection and cause enhancement of plant growth and increase yield. PGPF protected plants either by colonizing roots or by their metabolites. PGPF offer an advantage by protecting plants for more than 9 weeks and 6 week in the greenhouse and field. PGPF-induced plants limited pathogen spore germination and decreased the number of infection hyphae on the leaf, and increased lignification at places of attempted pathogen infection, thus reducing the pathogen spread. PGPF elicited increased activities of chitinascs, glucanases, peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase to C. orbiculare infection in cucumber plants. The role of PGPF in elevating cucumber defense response to pathogen infection suggests potential application of PGPF as biological control agents.

• Journal of Microbiology and Biotechnology
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• v.7 no.1
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• pp.13-20
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• 1997

Plant growth-promoting Psudomonas fluorescens GL20 was isolated from a ginseng rhizosphere on chrome azurol Sagar. P. fluorescens GL20 produced a large amount of hydoxamate siderophore in an iron-deficient medium. The siderophore showed significantly high specific activity of 20.2 unit. Using an in vitro antifungal test, P. fluorescens GL20 considerably suppressed growth of phytopathogenic fungus Fusarium solani, inhibiting spore germination and germ tube elongation. In pot trials of kidney beans with P. fluorescens GL20, disease incidence was remarkably reduced up to $68{\%}$ compared with that of F. solani alone, and plant growth was also increased nearly 1.6 fold as compared to that of the untreated control, promoting elongation and development of the roots. These results indicate that the plant growth-promoting activity of P. fluorescens GL20 can play an important role in biological control of soil-borne plant disease in a rhizosphere, enhancing the growth of plants.

• Korean Journal Plant Pathology
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• v.10 no.2
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• pp.119-122
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• 1994

Effects of organophosphorus fungicides on cutinase activity from Glomerella cingulata causing apple anthracnose and infection of apple were investigated. Diisoprophylfluorophosphate (DFP) inhibited the enzyme activity indicating that catalysis involves an active serine. In inhibition of the enzyme activity by organophosphorus fungicides, I50 (molar concentration of fungicide at which the enzyme activity is inhibited 50%) of Hinosan and Kitazin P were 26.3 $\mu$M and 427.7 $\mu$M, respectively. At concentration of 10-3 M DFP and organophosphorus fungicides, the infection of G. cingulata was inhibited to 5% in comparison with 15% infection at the unwounded healthy control, but increased to 30% when added with 1 mg/ml of cutinase. Mycelial growth was 36 mm in colony diameter on the medium added with 10-4M of hinosan in comparison with 90 mm of the untreated control, but was 90 mm on the medium added with 10-4M of kitazin P showing lower inhibition than hinosan. The spore germination was more than 60% at all the concentrations of both fungicides.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.40-46
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• 1998

For the comparison of the urushiol composition and biological acitivity between the fresh sap and fire distilled sap of lacquer tree(Rhus vernicifera), we analysed the urushiol composition by HPLC and EI-MS, and investigated the antioxidative , antimicrobial and anticancer acitivities according to solvent fractionations. There was no difference in the urushiol composition between fresh and fire distilled saps of lacquer tree. The hexane frqctionsof two saps showed a strong DPPH radical scaverging activity (RC50 : 7.0-7.5$\mu\textrm{g}$). They also showed a strong antifungal activity onthe spore germination of Cladosporium herbarum(MIC : 8$\mu\textrm{g}$/ml), whereas they have no or low activity against the bacteria(BAcillus subtilis , Escherichia coli). In addition , hexane and butanol fractions of two saps showed a strong inhibitory activity against cultured tumour cell lines (GI50 : 0.35, 12.29$\mu\textrm{g}$/ml) in vitro. These results confirm that the fresh sap and fire distilled sap might have the similar urushiol compositions and biological activities.

• Mycobiology
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• v.47 no.1
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• pp.105-111
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• 2019

Many of the fungicides and antibiotics currently available against plant pathogens are of limited use due to the emergence of resistant strains. In this study, we examined the effects of diphenyleneiodonium chloride (DPIC), an inhibitor of the superoxide producing enzyme NADPH oxidase, against fungal and bacterial plant pathogens. We found that DPIC inhibits fungal spore germination and bacterial cell proliferation. In addition, we demonstrated the potent antibacterial activity of DPIC using rice heads infected with the bacterial pathogen Burkholderia glumae which causes bacterial panicle blight (BPB). We found that treatment with DPIC reduced BPB when applied during the initial flowering stage of the rice heads. These results suggest that DPIC could serve as a new and useful antimicrobial agent in agriculture.

• Research in Plant Disease
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• v.15 no.2
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• pp.94-100
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• 2009

These experiments were conducted to improve the effect of seed disinfection on rice seed severely infected Bakanae disease by seed soaking into mixed solution of prochloraz EC and fludioxonil FS. We investigated the effects of various concentrations of two fungicides mixed solution on spore germination and mycelial growth of Fusarium fujikuroi. Mycelial growth was inhibited 100% at $10{\mu}g$/ml of prochloraz and 33.3% at $80{\mu}g$/ml of fludioxonil. Spore germination was inhibited 81.4% at $40{\mu}g$/ml of prochloraz. Interestingly, mixed solution of $5{\mu}g$/ml or $10{\mu}g$/ml of each fungicide inhibitied 100% of mycelial growoth and 99.2% of spore germination, respectively. Severely infected rice seeds soaked into mixed solution composed of $125{\mu}l$/ml of prochloraz and $50{\mu}l$/ml of fludioxonil showed 2.1% of disease symptoms compared to 20.4% of prochloraz $125{\mu}l$/ml, but higher concentrations of prochloraz decreased the seedling stand rate. When the seed soaking time was longer and temperature was higher, control effect on Bakanae disease was improved, but seedling stand was lower about 80% over $35^{\circ}C$.