• Journal of Microbiology and Biotechnology
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• v.8 no.4
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• pp.406-408
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• 1998

6-Epiophiobolin A, 3-anhydro-6-epiophiobolin A, and ophiobolin I were isolated from culture broth of Bipolaris sp. as cytotoxic agents against human tumor cells. Both 6-epiophiobolin A and 3-anhydro derivatives demonstrated significant cytotoxicity, having $IC_{50}$ values in the range of $1{\mu}g$/ml, which indicates that they have comparable cytotoxic potential with that of etoposide. The activity of ophiobolin I was, however, very weak compared with those of 6-epiophiobolin A and etoposide.

• Mycobiology
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• v.45 no.3
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• pp.123-128
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• 2017

A severe leaf spot, turning to foliage blight, was observed on leaves of Maranta leuconeura growing in a garden in Brazil (state of Rio de Janeiro) in 2015. A dematiaceous hyphomycete bearing a morphology typical of a helminthosporoid fungi was regularly found in association with diseased tissues. The fungus was isolated and pathogenicity was demonstrated through the completion of Koch's postulates. A morphology and molecular analysis led to the conclusion that the fungus belonged to the genus Bipolaris, which is characterized by having fusiform conidia, externally thickened and truncate hila and a bipolar pattern of germination. Additionally, homology of internal transcribed spacer and GAPDH sequences with sequences of other Bipolaris species, confirmed its generic placement. A phylogenetic study also indicated clearly that the fungus on M. leuconeura is phylogenetically distinct from related species of this genus, leading to the proposal of the new species Bipolaris marantae.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.575-582
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• 2011

This experiment was conducted to study the qualitative changes of grafted cactus after harvest and to examine the decomposition characteristics of pathogenic fungi which occurs or grows during the simulated shipping period. Plant materials with four varieties of Gymnocalycium mihanovichii var. friedrichii including, 'Hukwang', 'Huhong', 'Hwangwol', 'Yeunhwa' and two varieties of Chamaecereus silvestrii f. variegate such as 'Goldcrown' and 'Yellowcrown' were used. During the simulated shipping period, the fresh-weight, bulb diameter, carbon dioxide emission rate, and decomposition rate were observed. The regeneration rate and decomposition rate were observed for the grafted cactuses that were placed in a greenhouse environment with a temperature of $28{\pm}12^{\circ}C$ and humidity of $36{\pm}15.3%$ after 40 days of simulated shipping. There were reductions in the fresh-weight and bulb diameter in every variety as time passed while the carbon dioxide emission rate showed no meaningful difference by each variety. Furthermore, the decomposition rate in the scion was higher than in the stock. According to the analysis of pathogenic fungi by decomposition characteristics, Alternaria sp., Cladosporium sp., Colletotrichum sp., Fusarium sp., Penicillium sp. in G. mihanovichii var. friedrichii were found and Alternaria sp., Bipolaris sp., Cladospoirum sp. in C. silvestrii f. variegate were identified. Therefore, to maintain and improve the quality of grafted cactus, it is necessary to analyze the factors of decomposition from the time of harvest until the point of export and develop a process technology to minimize the decomposition rate.

• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.93-104
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• 2010

This study was conducted screening of the population densities of fungal pathogens and insect and observed the disease symptoms on the organic sweet corn seed producing field from 2008 to 2009. The dissemination spores, Alternaria sp., Cladosporium sp., Helminthosporium sp., Pyricularia sp., Collectotrichum sp., and Bipolaris sp., were detected and the three fungal spores from the front were observed for whole growth stage. Seed and seedling diseases were shown as the rotted seed and damping-off seedling caused by Penicillium sp. and Rhizoctonia sp.. The larva of Black cutworm cut down the root crown of seedlings. The damaged plants were ranged from 14% to 16%. On the Oriental corn borer, the population densities and the percentage of damaged plants were showed a low difference between two sweet corn varieties. The population densities of Oriental corn borer were scored as from 3.5 to 20.5 in 2008 and from 0.5 to 6 in 2009. Also the percentage of damaged plants were significantly increased until harvesting stage and was recorded from 7.5% to 21% in 2008 and from 1% to 46% in 2009. On the Corn leaf blight, the percentage of diseased plant were scored from 7% to 34% in 2008. The first occurrence of date was after June 18, and the percentage of diseased plant was continuously increased after August 21 and the values of diseased plants was ranged from 56% to 69% in 2009. On common smut, the percentage of diseased plant was recorded from 5% to 15% in 2008, and the first occurrence date were delayed as 17 days (July 17) and were showed less than 8% of diseased plants in 2009. Corn Southern Leaf spot was scored as average 11% at early stage and showed high score as 62% at September 19 in 2008. In 2009, the first occurrence date were advanced about 20 days (after June 8), and continuously increased up to 86% in 2009.

• Mycobiology
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• v.43 no.3
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• pp.210-217
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• 2015

A seed-borne fungus, Curvularia sp. EML-KWD01, was isolated from an indigenous wheat seed by standard blotter method. This fungus was characterized based on the morphological characteristics and molecular phylogenetic analysis. Phylogenetic status of the fungus was determined using sequences of three loci: rDNA internal transcribed spacer, large ribosomal subunit, and glyceraldehyde 3-phosphate dehydrogenase gene. Multi loci sequencing analysis revealed that this fungus was Curvularia spicifera within Curvularia group 2 of family Pleosporaceae.

• Research in Plant Disease
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• v.11 no.2
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• pp.93-97
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• 2005

In order to detect casual agents associated with ear blight of rice, seed samples of 'Ilmi-byeo' and 'Daesan-byeo', susceptible cultivars were collected from 28 regions on a nationwide scale. Finally 23 fungi including Bipolaris oryzae($10.3\%$), Alternaria alternata ($10.2\%$), Cladosporium sp. ($7.5\%$), Nigrospora oryzae($5.2\%$) and Phoma sorghina ($6.3\%$) from seeds of 'Ilmi-byeo', and 13 fungi including N. oryzae ($15.1\%$), A. alternata ($9.6\%$) and Curvularia lunata ($2.2\%$) from seeds of 'Daesan-byeo' were detected. In case of discolored seeds caused by rice ear blight, B. oryzae($15.5\%$), A. alternata ($5.5\%$), Fusarium graminearum ($8.0\%$), N. oryzae($5.2\%$) and P. sorghina ($4.5\%$) were detected even from the hulled rice of Ilmi-byeo.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.119.2-120
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• 2003

Seed-borne fungal pathogens on rice seeds were investigated in order to evaluate their effect on rice grain quality. Rice seeds of two cultivars, Ilmibyeo and Daesanbyeo were collected from 27 areas of Korea and the fungal parasites on seeds were isolated by using a blotter method. Isolation frequency and number of species were varied from collection areas of seed samples. A total 13 species of fungi were identified from the seeds. Among them, Altemana alternata was the most frequent over the country. Bipoiaris oryzae most commonly from Gyeongbuk and Jeonbuk, Alternaria padwickii from Jeonbuk, and Nigrospora oryzae from Choongnam. However Bipolaris. oryzae, Alternaria padwickii, and Nigrospora oryzae were the most frequently isolated fungi from Gyeongbuk and Jeonbuk, and Chungnam, respectively. B. oryzae, A. alternata, A. padwickii, and N. oryzae were dominants on Ilmibyeo showing 10.3％, 10.2％, 5.2％, and 5.2％ infection rate, respectively. While, N. oryzae, A alternata, and Cladosporium sp. were most frequently isolated fungi from Deasanbyeo revealing 15.1％, 9.6％, and 7.5％ infection rate, respectively. These fungi inhabiting on hulls or endosperms of rice seed might be considered as potential factors decreasing rice grain quality. Further investigation of the fungi on grain rice quality are undergoing.