• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.427-432
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• 2010

Rice bakanae disease caused by Fusarium fujikuroi is one of the most serious rice diseases in Korea. From 2006 to 2009, 118 F. fujikuroi isolates were collected from various regions of rice fields in Korea. Resistance assay of 118 F. fujikuroi isolates to prochloraz, tebuconazole, and benomyl, were performed using agar dilution method. To investigate inhibitory effects of the fungicides, minimum inhibitory concentration of mycelial growth (MIC) and effective concentration inhibiting mycelial growth by 50% ($EC_{50}$) for 118 isolates were calculated using Sigmaplot 8.02 (Antro, SPSS UK, Ltd). Based on the means of $EC_{50}$ values, baseline resistance values were determined as $0.5{\mu}g{\cdot}mL^{-1}$ for prochloraz, $5.0{\mu}g{\cdot}mL^{-1}$ for tebuconazole and $2.5{\mu}g{\cdot}mL^{-1}$ for benomyl. Number of resistant isolates to each fungicide was 17, 19 and 43 for prochloraz, tebuconazole and benomyl, respectively. Furthermore, 4 isolates showed the double resistance to both prochloraz and tebuconazole, 6 isolates to prochloraz and benomyl, and 11 isolates to tebuconazole and benomyl. Isolates CF366 and LF335 isolated from Gyeongbuk province were resistant to the three fungicides tested, prochloraz, tebuconazole and benomyl.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.120-124
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• 2007

Fusarium proliferatum KGL0401 was previously isolated from Physalis alkekengi var. francheti plant roots and exhibited higher GA productivity than wild type Gibberella fujikuroi. The :tim of this work was to find out an optimal culture condition for GA production. Various carbon(fructose, glucose, lactose, maltose, sucrose) and nitrogen($KNO_3$, urea, glycine, $NaNO_3,\;NH_4Cl$) sources were used for this study. GAs activities were analysed by gas chromatography and mass spectrometry(GC-MS). The highest yield of $GA_3$ was found in the growth medium supplemented with sucrose as carbon source and $NH_4Cl$ as nitrogen source. The optimum carbon-nitrogen concentration for $GA_3$ production was found to be 0.5 M:0.17 M. Supernatant was prepared from the culture fluid of F. proliferatum KGL0401 cultured for 7 days at 3 0'E and the 10 ul supernatant was treated with 2 leaf-rice seedling.

• Research in Plant Disease
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• v.25 no.4
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• pp.213-219
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• 2019

A total of 1,159 Fusarium strains were isolated from sorghum grown in Danyang and Youngwol in 2017 and 2018. The isolates were analyzed to reveal genetic, toxigenic and pathogenic characteristics. Phylogenetic analysis using TEF-1α and RPB2 genes showed that the samples were contaminated with at least 17 Fusarium species. Among them, F. graminearum, F. proliferatum, F. thapsinum, F. incarnatum, and F. asiaticum were dominant species. In F. graminearum and F. asiaticum, F. graminearum-15-acetyl deoxynivalenol chemotype and F. asiaticum-nivalenol chemotype were frequent. Six Fusarium species tested produced one or more mycotoxins, except F. thapsinum and FTSC 11. F. proliferatum and F. fujikuroi had FUM1 gene (76.0% and 81.6%, respectively) and some isolates produced high level of fumonisin (over 1,000 ㎍). F. proliferatum and F. thapsinum were more virulent than other species on sorghum. These results indicate that Fusarium species in sorghum might produce multiple mycotoxins.

• Research in Plant Disease
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• v.21 no.4
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• pp.326-329
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• 2015

Fusaric acid is a mycotoxin produced by species of the fungus Fusarium and can act synergistically with other Fusarium toxins. In order to develop a specific detection method for fusaric acid-producing fungus, PCR primers were designed to amplify FUB10, a transcription factor gene in fusaric acid biosynthetic gene cluster. When PCR with Fub10-f and Fub10-r was performed, a single band (~550 bp) was amplified from F. oxysporum, F. proliferatum, F. verticillioides, F. anthophilum, F. bulbicola, F. circinatum, F. fujikuroi, F. redolens, F. sacchari, F. subglutinans, and F. thapsinum, all of which were known for fusaric acid production. Whereas the FUB10 specific band was not amplified from Fusarium species known to be trichothecene producer. Because production of fusaric acid can co-occur in species that also produce fumonisin mycotoxins, we developed a multiplex PCR assay using the FUB10 primers as well as primers for the fumonisin biosynthetic gene FUM1. The assay yielded amplicons from fumonisin producers such as F. proliferatum and F. verticillioides, allowing for the simultaneous detection of species with the genetic potential to produce both types of mycotoxins.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.217-222
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• 2011

Job's tears (Coix lacryma-jobi) is native to East Asia, and grains of the plant are used as health food and medicinal material. Head blight symptoms of the plant were frequently observed during disease surveys in Korea from 2006 to 2008. The symptoms were characterized as discoloration of husks, and subsequently inside of mature grains were shriveled or emptied. One hundred fifty nine isolates of Fusarium species were obtained from the disease symptoms of the plant collected from several locations in the country. Out of the isolates, the most frequently isolated Fusarium species were F. graminearum (34%), F. proliferatum (14.5%), F. verticillioides (10.1%), F. equiseti (6.9%), and F. fujikuroi (6.3%). Other Fusarium species isolated were F. subglutinans, F. semitectum, F. poae, and F. sporodochioides. Elongation factor 1 alpha gene sequences of the isolates were used for phylogenetic analysis. Analyses of the sequences revealed that the isolates were confirmed to be identical with each reference species of NCBI GenBank. Pathogenicity tests showed that F. graminearum, F. proliferatum and F. verticillioides were strongly virulent to grains of Job's tears. The present study is the first report of head blight of Job's tears caused by Fusarium species in Korea.

• Applied Biological Chemistry
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• v.14 no.2
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• pp.171-175
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• 1971

Gibberella fujikuroi(imperfect stage Fusarium moniforme) a soil fungi is well known as the producer of plant growth regulator Gibberellins. The present work was planned for the isolation of the active strains of Gibberella fujikuroi from the native paddy soils. Twenty two strains were isolated from the infected rice seedlings collected from four local areas. Pyongtaek, Yesan, Tangjin and Sunchon and screened through the activity test for the production of Gibberellins. The strains P-105, Y-14 and T-58 yielded higher activity than the others isolated and the referred strain IAM-8048. The strains Y-5, Y-7, T-54 and S-152, however, were less promotive or rather inhibitory in the growth of rice seedlings. Six different kinds of culture media developed by Cross, Raulin-Thom, Borrow, West, Stodola and Kurosawa respectively were compared with each other for the production of Gibberellins and the best result was obtained with Raulin-Thom's media(glucose 16% and $NH_4NO_3$ 0.24%).

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.33-33
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• 2016

Mycotoxins are toxic secondary metabolites produced by fungi. They can be present in where agricultural-based commodities are contaminated with toxigenic fungi. These mycotoxins cause various toxicoses in human and livestock when consumed. Small grains including corn, barley, rice or wheat are frequently contaminated with mycotoxins due to infection mainly by toxigenic Fusarium species and/or under environment favorable to fungal growth. One of the most well-known Fusarium toxin groups in cereals is trichothecenes consisting of many toxic compounds. Deoxynivalenol (DON), nivalenol (NIV), T-2 toxin, and various derivatives belong to this group. Zearalenone and fumonisin (FB) are also frequently produced by many species of the same genus. In order to monitor Korean cereals for contamination with Fusarium and other mycotoxigenic fungal species as well, barley, corn, maize, rice grains, and soybean were collected from fields at harvest or during storage for several years. The fungal colonies outgrown from the grain samples were identified based on morphological and molecular characteristics. Trichothecene chemotypes of Fusarium species or presence of FB biosynthetic gene were determined using respective diagnostic PCR to predict possible toxin production. Heavy grain contamination with fungi was detected in barley, rice and wheat. Predominant fungal genus of barley and wheat was Alternaria (up to 90%) while that of rice was Fusarium (~40%). Epicoccum also appeared frequently in barley, rice and wheat. While frequency of Fusarium species in barley and wheat was less than 20%, the genus mainly consisted of Fusarium graminearum species complex (FGSC) which known to be head blight pathogen and mycotoxin producer. Fusarium composition of rice was more diverse as FGSC, Fusarium incarnatum-equiseti species complex (FIESC), and Fusarium fujikuroi species complex (FFSC) appeared all at considerable frequencies. Prevalent fungal species of corn was FFSC (~50%), followed by FGSC (<30%). Most of FFSC isolates of corn tested appeared to be FB producer. In corn, Fusarium graminearum and DON chemotype dominate within FGSC, which was different from other cereals. Soybeans were contaminated with fungi less than other crops and Cercospora, Cladosporium, Alternaria, Fusarium etc. were detected at low frequencies (up to 14%). Other toxigenic species such as Aspergillus and Penicillium were irregularly detected at very low frequencies. Multi-year survey of small grains revealed dominant fungal species of Korea (barley, rice and wheat) is Fusarium asiaticum having NIV chemotype.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.809-814
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• 2005

Gibberellins (GAs) play an important role in plant growth and development. Fifteen fungi were isolated from Physalis alkekengi var francheti plant roots, and among them, four isolates showed GA-production activity. A bioassay using waito-c rice was carried out with the culture fluid of the GA-producing fungi. The GA-producing fungi were cultured for 7 days in Czapek's liquid medium at $30^{\circ}C$, 120 rpm, under dark conditions. The culture broth was concentrated 30-fold and 10 ${\mu}l$ of that concentrate was applied to 2-leaf rice sprouts. The height of the rice seedlings treated with the culture fluid of isolate PA08 was 26 cm high, while that of the seedlings treated with the wild-type Gibberella fujikuroi was 13 cm high. As such, the plant growth-promoting activity exhibited by isolate PA08 was 2 times stronger than that exhibited by the wild-type G fujikuroi. The amounts of $GA_l,\;GA_3,\;GA_4,\;GA_7,\;GA_9,\;GA_{20}$, and $GA_{24}$ in the medium were measured using gas chromatography-mass spectrometry (GC-MS), and the quantities produced by isolate PA08 were 4.85 ng/ml, 4.79 ng/ml, 17.30 ng/ml, 6.01 ng/ml, 16.61 ng/ ml, 0.08 ng/ml, and 17.30 ng/ml, respectively. Isolate PA08 was also identified as Fusarium proliferatum KGL0401 by a genetic analysis of the nucleotide sequences of the internal transcribed spacer region of the ribosomal DNA.

• Research in Plant Disease
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• v.24 no.4
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• pp.313-320
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• 2018

Fusarium infection rate of the paddy rice grain after harvest seemed to be influenced by the average temperature from late July (before heading) to the end of September (during ripening). In case of 2010 and 2013 in which average temperature of the same period was similar, Fusarium infection was related to cumulative precipitation, cumulative precipitation days, and precipitation durations over two days. The distribution ratio of Fusarium species complex isolated from paddy rice grains after harvest was 57% in 2010 and 45% in 2013 for Fusarium graminearum species complex (FGSC), 35% and 50% for Fusarium incarnatum-equiseti species complex, and 8% and 5% for Fusarium fujikuroi species complex (FFSC). The distribution ratios of FGSC and FFSC were higher in 2010 than 2013. Among the total 26 promoted rice varieties, the 'Mihyang' showed resistant response against the natural infection with Fusarium species belonging to FGSC and the varieties of 'Nampyeong', 'Hi-ami'and 'Younghojinmi' showed resistant response against the natural infection with overall Fusarium pathogens. Majority of the promoted rice varieties could not be classified for resistance or susceptibility. These results are valuable as basic data to determine the resistance and susceptibility of rice variety against Fusarium spp. infection in the field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.355-365
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• 2015

Environment-friendly growth enhancers for rice are being promoted to reverse the negative impact of intensive chemical-based and conventional rice farming on yield sustainability and environmental problems. Several rhizosphere microorganisms and pyroligneous acids (PA) had demonstrated beneficial influence on growth, yield and grain quality of rice. Since most of the previous study had evaluated the effect of PGPR and PA on paddy rice singly, the effect of combined application of these on the growth and yield of paddy rice and on some soil chemical properties were determined. A four factorial pot experiment was conducted to evaluate the effect of PGPR, PA in combination with fertilizers and on different soil types. There were 54 treatment combinations including the control with three replications under complete randomized design. Plant growth parameters were evaluated using standard procedures during tillering and heading stages. Rice yield and some soil chemical properties were determined at harvest. Results showed that inoculation of Bacillus licheniformis and Fusarium fujikuroi enhanced plant growth by increasing the plant height which could be ascribe to its ability to promote IAA and GA production in plants. Inoculation of Rhizobium phaseoli enhanced chlorophyll content indicative to its ability to improve the N nutrition. However, these plant growth benefits during the vegetative stage were override by the fertilizer application effect especially during the maturity stage and grain yield. High fertilization rates on coarse-textured soil without nutrient loss resulted to high available nutrients and consequently high yield. Wood vinegar application however improved nutrient availability in soil which could be beneficial for improving soil quality. Further evaluation is necessary to fully assess the potential benefits that could be derived from inoculation of these organisms and wood vinegar application in different soil environment especially under different field conditions.