• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.211-215
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• 1977

The Sporulation of Didymella bryomiae were observed under diurnal cycles of light/darkness of near ultraviolet light (NUV) and artificial daylight (ADL) and continous darkness in eight isolates growing on PDA and V-8 juice agar. Light stimulated pycindial and perithecial formation of this fungus on potato dextrose agar and V-8 juice agar. Sprulation was poor in darkness, but some isolates were able to produce pycnidia and perithecia in the absence of light. Perithecial formation was much better under artificial daylight (ADL) on V-8 juice agar than those grown under near ultraviolet light (NUV). In general, cultures grown on V-8 juice agar sporulated better than cultures grown on PDA under three setsof light condition. Most of the pycnidiospores obtained from each isolates of this fungus grown on PDA were non-septate and microtype, but macrotype of non-septate and uniseptate pycnidiospores were produced on V-8 juice agar. Pycnidiospore produced on V-8 juice agar were similar to those produced on the radicle of naturally infected seeds. The appearance of perithecia were quite distinctive from pycnidia. The mature perithecia were darker than pycnidia and whitish spore masses formed on the ostiole of perithecia.

• Korean Journal Plant Pathology
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• v.14 no.4
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• pp.339-344
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• 1998

Since the leaf inoculation procedures are time-consuming and require considerable growth chamber space, a rapid dioassay method for screening of pathogenicity of Didymella bryoniae, a casual agent of gummy stem blight in watermelon, was established in this paper. The method produced reliable results within 8 days ( 5 days for growing seedlings and 3 days for rapid disease response in the seedlings). After contaminants in the root of 4~5 day-old seedlings had been washed using sterilized water, 5 seedlings were dipped into a vial containing 12 ml of conidial suspension (106 cells/ml). After the vials were placed in a growth chamber (22$^{\circ}C$, RH 50%, 14hr light/10hr darkness) for 3 days, susceptibility and resistance of cultivars were determined by the degree of disease response on cotyledon. The result of obtained by the dip-inoculation method was well coincided with the results by the leaf inoculation procedures and the result that had been observed for several years in the field. Screening of collected watermelon cultivars by the dip-inoculation method revealed that all the 21 domestic cultivars collected were susceptible and only 3 foreign cultivars (PI 189225, PI 482322 and IT 188207) were resistant among 18 cultivars A cucumber cultivar (Marketer) and bitter cucumber were proven to be resistant against the D. bryoniae among 8 other different cucurbits tested. The SDS-PAGE patterns of total proteins from a susceptible (Keumcheon) and a resistant (PI 189225) watermelon cultivars were compared 0, 12, 24 and 36 hrs after inoculation. The amounts of two distinct protein bands (24 kDa and 70 kDa) were gradually increased after inoculation in both cultivars.

• The Korean Journal of Mycology
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• v.10 no.1
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• pp.7-13
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• 1982

Habit characteristics of imperfect and perfect stage of D. bryoniae encountered on naturally infected seeds of cucumber and pumpkin were studied by the blotter method and compared with those grown on Difco potato dextrose agar (PDA), V-8 juice agar and water agar leaf medium (WALM). Most of the pycnidiospores obtained from each isolate of this fungus grown on PDA were non-septate and microtype. Non-septate pycnidiospores were predominanted in all isolates, but a macrotype of the non-septate and a number of uniseptate pycnidiospores were produced on V-8 juice agar and water agar leaf medium. On seed the pycnidiospores were mostly non -septate, but rarely uniseptate ones were also found. On radicle of cucumber seed, the pycnidiospores were non-septate and uniseptate but small percentage biseptate with somewhat constricted at septa. Pycnidiospores produced on V-8 juice agar and water agar leaf medium were similar to those produced on seeds. In the present investigation the perithecia were mostly globose to subglobose with apical papillate ostiole and whitish spore masses formed on the ostiole of perithecia, either on naturally infected seed or on culture media. The mature perithecia were dark brown to black. They were partially embedded or erumpent on seed coat and culture media. The perithecia varied in size within a much narrower range than the pycnidia. But perithecial formation of this fungus on PDA, V-8 juice agar, WALM and seed varied considerably depending upon isolate and culture media.

• Environmental Analysis Health and Toxicology
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• v.18 no.2
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• pp.131-136
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• 2003

Anti-fungal materials producing bacteria were isolated from soil by bennett's agar and actinomycete isola-tion agar medium. The bacterla were identified as synonym of Actinomycetes. Based on the data obtained from its morphological and colony characteristics. The medium for production of anti-fungal materials was YEME (yeast extract 4 g, malt extract l0g, glucose 4 g, D.W 1ι, pH 7.0${\pm}$0.2). The culture conditions were 30$^{\circ}C$, 7 days and 200 rpm in shaking incubator. No. 13, No. 15 and No.28 strains were produced anti-fungal materials against fungal plant pathogens. Specially, The No. 28 strain showed a powerful biopesticide activity and broad spectrum effects of anti -fungal materials on Collectrichum coccodes, Botrytis cinerea, Cladosporium cucumerinum, Didymella bryoniae.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.165-168
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• 2004

An anti-fungal material producing actinomycete was isolated from domestic soil. This strain was identified as Streptomyces albogriseus by 16S rDNA sequence. YEME (yeast extract 4g, malt extract 10g, glucose 4g, D.W 1l , pH $7.0{\pm}0.2$) medium was used for production of anti-fungal materials. S. albogriseus was cultured in a shaking incubator for 2 weeks at 150 rpm and $25{\pm}1^{\circ}C$. An anti-fungal material produced by S. albogriseus was identified at 340nm by uv/vis- spectrometer and it showed powerful anti-fungal activity. This is the first report that secondary metabolite produced by S. albogriseus showed an activity against phytopathogenic fungi such as Collectrichum coccodes, Botrytis cinerea, Cladosporium cucumerinum, Didymella bryoniae.

• Journal of Environmental Health Sciences
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• v.31 no.1
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• pp.31-38
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• 2005

An anti-fungal material produced by actinomycetes was isolated from domestic soil. This actinomycetes was identified as Streptomyces albogriseus by 16S rDNA sequence. YEME (yeast extract 4 g, malt extract 10 g, glucose 4 g, D.W 1l, pH 7.00.2) medium was used for production of anti-fungal materials. S. albogriseus was cultured in a shaking incubator for 2 weeks at 150 rpm and $25^{\circ}C$. An anti-fungal material produced by S. albogriseus was identified at 340 nm by uv/vis- spectrometer and it showed powerful anti-fungal activity. This is the first report that secondary metabolite produced by S. albogriseus showed an activity against phytopathogenic fungi such as Collectrichum coccodes, Botrytis cinerea, Cladosporium cucumerinum, Didymella bryoniae.

• The Plant Pathology Journal
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• v.16 no.6
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• pp.312-317
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• 2000

The selected five plant growth-promoting rhizobacteria (PGPR) strains, WR8-3 (Pseudomonas fluorescens), WR8-6 (P. putida), WR9-9 (P. fluorescens), WR9-11 (Pseudomonas sp.), and WR9-16 (P. putida) isolated in the rhizosphere of watermelon plants were tested on their growth promotion and control effect against gummy stem rot of watermelon. Strains, WR8-3 and WR9-16 significantly increased stem length of watermelon, and there was a little increase in leaf area, fresh weight and root length when strains, WR8-3, WR9-9 and WR9-16 were treated. Generally, seed treatment was better for plant growth promotion than the soil drench, but there was no significant difference. Seed treatment and soil drench of each bacterial strain also significantly reduced the mean lesion area (MLA) by gummy stem rot, but there was no significant difference between the two treatments. At initial inoculum densities of each strain ranging from 10$^6\;to\;10^{15}$ cfu/g seed, approximately the same level of disease resistance was induced. But resistance induction was not induced at the initial inoculum density of 10$^3$ cfu/g seed. Resistance was induced by treating the strains, WR9-9, WR9-11 and WR9-16, on all of four watermelon varieties tested, and there was no significant difference in the decrease of gummy stem rot among varieties. Populations of the strains treated initially at log 9-10 cfu/g seed, followed with a rapid decrease from planting day to 1 week after planting, but the population density was maintained above log 5.0 cfu/g soil until 4 weeks after planting. Generally no or very weak in vitro antagonism was observed at the strains treated excepting WR9-11. Rifampicin-resistant bacteria which had been inoculated were not detected in the stems or leaves, which suggesting that the bacterium and the pathogens remained spatially separated during the experiment. This is the first report of rsistance induction in watermelon to gummy stem rot by PGPR strains.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.63-69
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• 2006

We isolated a bacterium which produces antifungal substances from the Lake of Saimaa soils in Fin-land. The isolated strain was identified as Bacillus sp. and shown a strong antifungal activity on plant pathogenic fungi. Bacillus sp. KMU-1011 produced maximum level of antifungal substances under incubation aerobically at $24^{\circ}C$ for 48 hours in nutrient broth containing 1.0% glucose and 1.0% polypeptone at 180 rpm and initiated pH adjusted to 6.0. Precipitate of culture broth by $30{\sim}60%$ ammonium sulfate precipitation exhibited strong antifungal activity against Botrytis cinerea KACC 40573 by dry cell weight. Chloroform extract of cultured broth also shown fungal growth inhibitory activity against C. gloeosporioides KACC 40804, D. bryoniae KACC 40669, F. oxysporum KACC 40037, F. oxysporum KACC 40052, F. oxysporum f. sp. radicis-lycopersici KACC 40537, F. oxysporum KACC 40902, M. cannonballus KACC 40940, P. cambivora KACC 40160, R. solani AG-1 KACC 40101, R. solani AG-4 KACC 40142, and S. scleotiorum KACC by agar diffusion method.