• The Korean Journal of Mycology
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• v.20 no.4
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• pp.337-346
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• 1992

Trichoderma spp. are an effective control agent for damping-off or other plant diseases. The interaction between. T. hamatum and Rhizoctonia solani on the rhizosphere or surface soil were examined to assess the possible roles of antibiosis or competition in the mechanisms of biological control agents as a basic research. In a proportional comparison, total bacteria, fungi, actinomycetes and Trichoderma spp were 65%, 8.8%, 25.9% and 0.28% respectively in their distribution in the soil. Among Trichoderma spp isolated, the 5 species of Trichoderma spp were indentified as T. koninggii, T. pseudokoninggii, T. aureoviridi, T. hamatum and T. viride respectively. In a mycoparasitic test, one isolate of T. hamatum strain Tr-5 showed an enzymatic ability to break fungal hyphae into piecies and infected on the R. solani hyphae showing a parasitism. Spore germination of the all isolates of Trichoderma spp showed a 1.7-7.3% of germination in natural soil conditions, but the percentage was high in sterile soil indicating all the natural soil were fungistatic on conidia of Trichoderma spp. In rhizosphere competent assay in pea plant, the antagonistic T. hamatum, T. viride, T. koninggii, T. pseudokoninggii showed a colonizing upper soil depth in rhizosphere around 1-3 cm in root zone, but the colonizing ability was much reduced along the deeper the soil depth. Propagule density was decreased in deeper the soil layer. Disease development rate treated alone with plant pathogens, Fusarium solani, Rhizoctonia solani, Cylindrocarpon destructans increased, but disease incidence rate reduced in treatment with combinations with antagonistic T. hamatum strain Tr-5.

• The Korean Journal of Mycology
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• v.13 no.2
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• pp.105-109
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• 1985

Isolates of the different species groups of Trichoderma from the mushroom culture beds were identified according to Rifai's classification and influence of antibiotics produced by them against the oyster mushroom was examined. Trichoderma islolates were identified as Trichoderma hamatum, Trichoderma viride and Trichoderma koningii. Among the Trichoderma isolates, fungistatic action of Trichoderma viride was found to be most remarkable. Pleurotus ostreatus and Pleurotus sajor-caju were the most susceptable of the edible mushrooms tested, followed by Lentinus edodes, Flammulina velutipes and Auricularia auricula. A needle-shaped crystal gained from the chloroform extract of the culture filtrate of Trichoderma viride repressed distinctively the mycelial growth of the oyster mushroom. The grade of repression of the crystal at 500ppm and 1/10 aequ­ous solution of the chloroform extract against the oyster mushroom, seemed equal to that of cycloheximide at $100{\sim}200ppm$.

• Korean Journal of Microbiology
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• v.22 no.3
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• pp.157-165
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• 1984

Seasonal and spatial variations in propagule numbers of Trichoderma species were investigated every other month for one year in deciduous and coniferous forest soils and evaluated the relationships of Trichoderma spp. populations to soil environmental factors. The total population of Trichoderma spp. increased until summer and then declined until winter. The yearly mean frequency of Trichoderma spp. exceeded 1.4% of total fungal propagules in two sites. Decreases of absolute an relative propagule numbers of Trichoderma spp. with increasing soil depth were found and variation in Trichoderma spp. propagules caused by differences in soil depth ($0{\sim}50cm$) was greater than that caused by differences in sampling time. The most common species occurring in two sites was T. viride, followed by T. polysporum, T. koningii, and T. hamatum. Individual species of Trichoderma showed diferent abundance trend in accordance with sampling time. T. viride was dorminant from spring to autumn, while T. polysporum dominated over the other speicies in winter. Variations in propagule number of Trichoderma sppp. were principally mediated by the actions of biotic environmental factors rather than by the direct effects of abiotic factors. In multiple-regression analyses, 48% of the total vaiation in Trichoderma spp. propagules in deciduous site could be accounted for by total fungal propagules and soil CMCase actvity. In coniferous site, 65% of total variation could be accounted for by total fungal and bacterial propagules, moisture content and organic carbon content.

• Korean Journal of Microbiology
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• v.18 no.2
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• pp.73-90
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• 1980

Ninerty one of Trichoderma spp. were isolated from ginseng growing bed, dead trees and muchroom in Korea from March 1978 to June 1979. Six species were identified as T. hamatum(13 strains), T, roningii(17 strains), T. aureoviride(4 strains), but other six strains(strain No. 111, 125, 127, 130, and 503) unidentified by Rifai's key. The reason which is not identified is as following. According to Rifai's key, phialid, phialospore and colony's colour of four strains (strain No. 125, 126, 127 and 130) are like T. longibrachiatum, but they are different from Rifai's method, because sterile-hypha often appears. the fature of standard strain ATCC no. 13631 T. longibrachiatum is like ster9ile-hypha that is used strains in this experiment. The morphology of strain No.503 is the same as T. hamatum except phialospore. Gnerally, T. hamatum's phialospore is subcylindrical, but strain No. 503 is regular ovoid. Therefore, strain No.503 cannot be identified by Rifai's key. The property, strain No.111's phialid is very irregular $(5{\sim}20{\times}2{\sim}2.5{\mu})$) and its phialospore $(4.0{\sim}6.0{\times}3.0{\sim}4.0{\mu})$) is subcylindrical, is uncomfortable to Rifai's method. The standard strains used in this experiment are 7 kinds of Trichoderma spp. received from ATCC.

• The Korean Journal of Mycology
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• v.30 no.2
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• pp.147-151
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• 2002

Trichoderma spp. are the aggressive causal agents for green mold disease on oyster mushroom (Pleurotus spp.) cultivation. Antifungal bacteria (KATB 99121, KATB 99122 and KATB 99123 strains) were isolated from the compost for Pleurotus ostreatus. Among these bacterial strains, KATB 99121 strain showed an excellent inhibitory activity to the pathogens for green molds such as T. harzianum, T. viride and T. hamatum and an animal pathogen, Candida albicans, but did not affect on the culture of Pleurotus ostreatus (2209, Chunchu 2 and Wonhyung strains). KATB 99121 strain secreted amylolytic, proteolytic and cellulolytic exoenzymes. KATB 99122 and KATB 99123 strains excreted amylolytic, proteolytic, cellulolytic, lipolytic exoenzymes and showed ${\beta}$-glucosidase activity. Further studies will be conducted on the development of microbial fungicides using the antagonistic bacteria for the control of green mold disease on Pleurotus spp.

• Journal of Microbiology and Biotechnology
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• v.21 no.1
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• pp.5-13
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• 2011

In this study, seven Trichoderma species (33 strains) were classified using secondary metabolite profile-based chemotaxonomy. Secondary metabolites were analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS) and multivariate statistical methods. T. longibrachiatum and T. virens were independently clustered based on both internal transcribed spacer (ITS) sequence and secondary metabolite analyses. T. harzianum formed three subclusters in the ITS-based phylogenetic tree and two subclusters in the metabolitebased dendrogram. In contrast, T. koningii and T. atroviride strains were mixed in one cluster in the phylogenetic tree, whereas T. koningii was grouped in a different subcluster from T. atroviride and T. hamatum in the chemotaxonomic tree. Partial least-squares discriminant analysis (PLS-DA) was applied to determine which metabolites were responsible for the clustering patterns observed for the different Trichoderma strains. The metabolites were hetelidic acid, sorbicillinol, trichodermanone C, giocladic acid, bisorbicillinol, and three unidentified compounds in the comparison of T. virens and T. longibrachiatum; harzianic acid, demethylharzianic acid, homoharzianic acid, and three unidentified compounds in T. harzianum I and II; and koninginin B, E, and D, and six unidentified compounds in T. koningii and T. atroviride. The results of this study demonstrate that secondary metabolite profiling-based chemotaxonomy has distinct advantages relative to ITS-based classification, since it identified new Trichoderma clusters that were not found using the latter approach.

• Korean journal of applied entomology
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• v.26 no.2 s.71
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• pp.89-97
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• 1987

Antagonistic microorganisms from rhizosphere soil were isolated, identified, and applied successfully as the biocontrol agents of damping-off caused by Rhizoctonia spp. Rhizosphere antagonists isolated from rhizosphere soil were identified as Trichoderma viride, T. harzianum, T. hamatum, T. polysporum, Gliocladium sp., Pseudomonas fluorescence, P. stutzeri, P. cepacia, Enterobacter sp., Serratia sp. and Erwinia herbicola. Of these, the most promising ones in vitro were T. virdie, T. harzianum, Gliocladium sp., Serratia sp., P. stutzeri, and P. cepacia. These above six antagonists were efficient in reducing disease incidence to $40{\sim}70%$ when the reselected rhizosphere antagonists preparations were applied to the soil at $10^6$ propagules per gram. Among six antagonists, T. viride was the most promising biocontrol agents against R. solani isolates in soil. The suppressive effect was more evident in steam-sterilized soil than in non-sterilized field soil.