• Current Research on Agriculture and Life Sciences
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• v.31 no.4
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• pp.245-249
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• 2013

In 2008, leaf blight symptoms were observed on several Chinese chive farms in Sangju. The Pathogenicity of the isolate was confirmed by artificial inoculation, where the pathogen exhibited a strong pathogenicity toward healthy plants. Morphological classification identified the isolate as from the Fusarium genus. For further analysis, PCR and phylogenetic classification were performed with ITS region and 28S rRNA gene which are commonly used for fungal identification. However, the results provided a poor resolution. To solve this problem, we analyzed translation elongation factor 1-alpha (TEF-$1{\alpha}$) gene. The analyzed results using TEF-$1{\alpha}$ gene indicated that the isolate was F. proliferatum. Therefore, it is assumed that TEF-$1{\alpha}$ gene is important when Fusarium sp. was identified using molecular classification method.

• Korean Journal of Microbiology
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• v.27 no.4
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• pp.342-347
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• 1989

by use of HCl-Giemsa technique and light microscope, dividing vegetative nuclei in hyphae of Fusarium species were observed and the results are summerized. The chromosome number of these fungi was ranged 4 to 8. Of the 20 strains, the highest haploid chromosome number is 8 in F. solani S Hongchun K4, F. moniliforme (from banana) and F. raphani (from radish). The lowest is 4 in F. sporotrichioides NRRL 3510 and F. equiseti KFCC 11843 IFO 30198. F. solani 7468 (from Sydney), F. solani 7475 (from Sydney), F. oxysporum(from tomato). F. roseum (from rice), F. sporotrichioides C Jngsun 1, F. equiseti C Kosung 1 and F. avenaceum 46039 are n=7. F. moniliforme (from rice) F. graminearum, F. proliferatum 6787 (from Syndey), F. proliferatum 7459 (from Synder) and F. anguioides ATCC 20351 are n=6. F. moniliforme NRRL 2284, F. poae NRRL 3287 and F. trincinctum NRRL 3299 are n=5. From these results, it may be concluded that the basic haploid chromosome number of the genus Fusarium is 4 and mat have been evolutionary variation of chromosome number through aneuploidy and polyploidy.

• Research in Plant Disease
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• v.10 no.4
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• pp.260-267
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• 2004

Fusarium spp. were isolated from the postharvest fruit rot of oriental melon fruits at commercial fruit markets in Korea during 2001 to 2003. The decayed fruits were covered with the fungal mycelia and eventually soft rotted. The disease started at the fruit stalk area, the calyx end of the fruit and skin of fruit. As the disease advanced, white to pinkish mycelia covered with the surface of decayed fruit. The cultural and morphological characteristic of Fusarium spp. were compared with descriptions of those reported previously, and identified as Fusarium equiseti, F. graminearum, F. moniliforme, F. proliferatum, F. sambucinum, and F. semitectum. Pathogenicity of the isolates was proved by artificial wound and unwound inoculation onto the healthy fruits. Two days after inoculation, aerial mycelia were noticed on the wound inocultion region of the fruit and developed soft rot symptoms. Although Fusarium spp. causing fruit rot disease in oriental melon have been reported in Korea, identification of the those species was not described. Therefore, this is the first report of Fusarium spp. causing postharvest fruit rot on oriental melon in Korea.

• Research in Plant Disease
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• v.22 no.2
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• pp.111-115
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• 2016

Wilt disease appeared the first in greenhouse-grown safflower (Carthamus tinctorius) in Jeonju, Korea. With the advancement of the disease, the infected plants were withered and died. In order to investigate the causal organism of this symptom disease, fungus was isolated from the infected plants and cultured on potato dextrose agar medium. The fungus showed the white or orange colony color with aerial mycelium. Macroconidia were from falcate to straight, usually 3-5 septate with $38.0-66.7{\times}2.9-4.4{\mu}m$. The fungus was inoculated to a new safflower plant and caused the same wilt. With morphological characters and pathogenicity results, sequence analyses (internal transcribed spacer ribosomal DNA and translation elongation factor $1{\alpha}$) suggested that, the isolated fungus is Fusarium proliferatum. This is the first report of Fusarium wilt disease caused by F. proliferatum on safflower in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2002.11a
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• pp.100.2-101
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• 2002

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.25-25
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• 2014

Three species of Fusarium, F. fujikuroi, F. verticillioides and F. proliferatum, are known to be associated with bakanae disease of rice [1, 2]. F. fujikuroi infects rice flowers and survive in endosperm and embryo of the seeds. Infected seed is an important source of primary inoculum of pathogens [3]. Seeds of rice (Oryza sativa cv. Boramchan) collected from bakanae-infected field were found to be 96% infected with Fusarium sp., 52% with F. fujikuroi, 42% with F. verticillioides, and 12% with F. proliferatum as determined by incubation method and species-specific PCR assays. F. fujikuroi was detected at lemma/palea, endosperm and embryo whereas F. verticillioides and F. proliferatum were recovered only from lemma/palea by means of component plating test. Seed disinfection methods have been developed to control bakanae disease and prochloraz has been most widely used for rice seeds. Two chemicals formulated with prochloraz (PC 1) and prochloraz + hexaconazole (PC 2) that inhibit biosynthesis of ergosterol strongly reduced the incidence of Fusarium spp. on selective media to 4.7% and 2.0%, respectively. Disease symptoms of rice seedlings in nursery soil were alleviated by chemical treatment; seedlings with elongated leaves or wide angle between leaf and stem were strikingly reduced from 15.6 to 3.2% (PC 1) and 0 (PC 2), stem rots were reduced from 56.9 to 26.2% (PC 1) and 32.1% (PC 2), and normal seedling increased from 0.4 to 13.3% (PC 2). Prochloraz has some disadvantages and risks such as the occurrence of tolerant pathogens [4] and effects on the sterol synthesis in animals and humans [5]. For these reasons, it is necessary to develop new disinfection method that do not induce fungal tolerance and are safe to humans and animals. Chlorine dioxide ($ClO_2$), that is less toxic, produces no harmful byproducts, and has high oxidizing power, has been reported to be effective at disinfection of several phytopathogenic fungi including Colletotrichum spp. and Alternaria spp. [6]. Gaseous $ClO_2$ applied to rice seeds at a concentration of 20 ppm strongly suppressed mycelial growth of Fusarium fujikuroi, F. verticillioides and F. proliferatum. The incidence of Fusarium spp. in dry seed with 8.7% seed moisture content (SMC) tended to decrease as the concentration of $ClO_2$ increased from 20 to 40 ppm. Applying 40 ppm $ClO_2$ at 90% relative humidity, incidence was reduced to 5.3% and resulted in significant reduction of disease symptoms on MS media. In nursery soil, stem rot was reduced from 56.9 to 15.4% and the number of normal seedlings increased from 0.4 to 25.5%. With water-soaked seeds (33.1% SMC) holding moisture in the endosperm and embryo, the effectiveness of disinfection using $ClO_2$ increased, even when treated with only 20 ppm for four hours. This suggests that moisture was a key element for action of $ClO_2$. Removal of the palea and lemma from seeds significantly decreased the incidence of Fusarium spp. to 3.0%. Seed germination appeared to decrease slightly by water-soaking at $30^{\circ}C$ because of increased SMC and by physical damage of embryos from hulling. These results indicate that the use of gaseous $ClO_2$ was effective as a means to disinfect rice seeds infected with Fusarium spp. and that moisture around the pathogens in the seed was an important factor for the action of $ClO_2$. Further investigations should be conducted to ascertain the best conditions for complete disinfection of Fusarium spp. that infect deep site of rice seeds.

• The Plant Pathology Journal
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• v.33 no.4
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• pp.410-423
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• 2017

Pathological interrelations of two soil-borne diseases in cucurbits (watermelon, oriental melon, shintosa and cucumber) caused by Fusarium isolates (FI) and the root-knot nematode (RKN), Meloidogyne incognita were characterized by the fusarium disease severity index (DI), RKN gall index (GI) and eggmass index (EI) in inoculation tests using FI and RKN. Virulence of FI as determined by DI at 4 weeks after inoculation was mostly in the higher order of Fusarium proliferatum F6, F5 and Fusarium oxysporum f. sp. melonis or Fusarium oxysporum f. sp. niveum with no significant differential interactions among the cucurbits and RKN co-infection. Significant increases of DI due to RKN coinfection were noticed in watermelon and oriental melon infected with F. proliferatum isolates, suggesting the DI increase due to RKN coinfection may depend upon the virulence of FI relative to aggressiveness of RKN on the cucurbits. For the coinfection of FI and RKN, GI and EI were mostly reduced logarithmically with the increase of DI, largely more in EI than GI, in all cucurbits except for shintosa. Microscopic examination of the root tissues showed histopathological features characteristic to infection types; formation of fungal hyphae and/or spores and plant defense structures (tyloses and mucilage) in variable degrees and formation of giant cells at variable developmental stages and with variable cytoplasmic depletion or degeneration which were visualized in relations with the values of DI, GI and EI. These findings will be helpful to develop control strategies of the soil-borne disease complex based on their pathological characteristics.

• Research in Plant Disease
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• v.17 no.3
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• pp.369-375
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• 2011

Fusarium verticillioides (teleomorph: Gibberella moniliformis), a member of the Gibberellea fujikuroi species complex, causes rots of corn stalks and ears, and produces a group of mycotoxins known as fumonisins that are harmful to animals and humans. Here, we focus on the development of a species-specific PCR primer set for differentiating F. verticillioides from other fumonisin-producing Fusarium species belonging to the species complex, such as F. proliferatum, F. fujikuroi, and F. subglutinans that are frequently associated with corn. The specific primers (RVERT1 and RVERT2) derived from the nucleotide sequences of RNA polymerase II beta subunit (RPB2) gene amplified a 208 bp-DNA fragment from only F. verticillioides isolates among the potential fumonisin-producing species examined; all of these isolates were shown to carry FUM1 required for fumonisin biosynthesis. The PCR detection limit using this specific primer set was approximately 0.125 pg/${\mu}l$ genomic DNA of F. verticillioides. In addition, the F. verticillioides-specfic fragment was successfully amplified from genomic DNAs of corn samples contaminated with Fusarium spp. This primer set would provide a useful tool for the detection and differentiation of potential fumonisin-producing F. verticillioides strains in cereal samples.

• The Korean Journal of Pesticide Science
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• v.12 no.3
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• pp.277-282
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• 2008

To assess the resistance to prochloraz, $EC_{50}$ values of Fusarium isolates obtained from rice seed were investigated through the agar dilution method. $EC_{50}$ value of 36 isolates of Fusarium spp. to prochloraz ranged from 0.020 to $1.78{\mu}g\;mL^{-1}$ with an average of $0.25{\mu}g\;mL^{-1}$. According to the species of Fusarium, the average $EC_{50}$ value was fluctuated; $0.091{\mu}g\;mL^{-1}$ for F. moniliformis, $0.11{\mu}g\;mL^{-1}$ for F. proliferatum and $0.31{\mu}g\;mL^{-1}$ for F. fujikuroi. The resistant baseline was decided at $0.5{\mu}g\;mL^{-1}$ to determine if the isolate was resistant to prochloraz or not. Based on the resistant baseline, the ratio of resistant isolates was 14%. There was no correlation between the resistance to prochloraz and the pathogenicity of Fusarium spp. on rice seedlings. The resistant isolates of F. fujikuroi did not show the cross-resistance to other sterol biosynthesis inhibiting fungicides, triflumizole, hexaconazole, difenoconazole and tebuconazole.

• Research in Plant Disease
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• v.25 no.4
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• pp.157-163
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• 2019

This study aimed to assess the incidence and distribution of toxigenic fungi in Korean oat. Toxigenic fungi were isolated from oat samples collected from 12 oat fields from heading to harvest in 2017 and 2018. A total of 745 fungal colonies were isolated based on morphology and identified using marker genes. About 92% of the fungal isolates were Fusarium spp. and others were Penicillium (5.9%) and Aspergillus (2.1%). Fusarium isolates comprised mostly of F. asiaticum (83.1%), followed by F. incarnatum (5.4%), F. proliferatum (3.5%), F. fujikuroi (2.8%), F. tricinctum species complex (FTSC) 11 (1.5%) and F. graminearum (1.0%). About 97% of F. asiaticum was nivalenol type, and 3-acetyl deoxynivalenol (3.2%) and 15-acetyl deoxynivalenol (0.4%) types also were found. Pathogenicity test of the selected Fusarium isolates revealed that F. asiaticum isolates have a wide range of virulence depending on the tested plants. F. graminearum and FTSC 11 isolates from blighted spikelets were the most virulent in naked oat. All Fusarium isolates (n=18) except one (FTSC 11) produced nivalenol (0.2-7.6 ㎍/g), deoxynivalenol (0.03-6.1 ㎍/g), and zearalenone (0.1-27.0 ㎍/g) on rice medium. This study is first report that F. asiaticum causes Fusarium head blight disease of oat in Korea. These findings demonstrate the dominance of F. asiaticum in oat agroecosystems as in rice, wheat and barley in Korea.