• Korean journal of applied entomology
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• v.11 no.2
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• pp.101-107
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• 1972

This experiment was conducted in order to determine the fungi associated with ear blight of rice and their chemical control. 1, Pyricularia oryzes, Helminthosporium oryzne, Epicoccum purpurascens, Curvularia lunata, Cladosporium cladosporoides and Alternaria tenuis et al. were mainly detected in large quantities from the discolored seeds of recommended varieties but Trichoconis padwickii, Fusarium dimerum, and Nigrospora oryzae were mainly detected from Tongil. 2. Pyricularia oryzae, Nigrospora oryzae, and Curvularia lunate et at. were from the necks; Helminthosporium oryzae, Trichoconis padwickii, Stemphylium sp. , Cladosporium cladosporoides, and Alternaria tenuis et at. were from the branches of ear; and Phoma spp. was mainly detected from the kernels. 3. In the laboratory Difolatan WP $0.13\%$ gave good control of Helminthosporium oryzae, Cladosporium cladosporoides, and Alternaria tenuis, et al.; and Dithane M-45 WP $0.2\% gave especially good control of Pyricularia oryzae, Trichoconis padwickii, and Curvularia lunate. 4. In field experiments, the appropriate date of chemical spray was milk ripening stage or panicle emergence stage. Under these conditions Hinosan Ec and Kasugamin Ec were more effective than Difolatan WP and Dithane M-45 WP. However, the assessment of ear blight was complicated by a severe outbreak of neck blast.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.362-368
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• 2008

In order to isolate novel oligotrophic bacteria exhibiting antifungal activities, soils were collected from pepper-cultivated fields of Yeongyang, Jecheon, Nonsan, Eumsong and Goesan area in Korea. From soils in pepper cultivated area, a total of 9,354 strains were isolated as oligotrophic bacteria by the R2A dilution method. Among 9,354 oligotrohic bacteria candidates, 1A strain was selected by screening against Phytophthora capsici causing phytophthora blight of hot pepper in the greenhouse and field. The strain was identified as Bacillus vallismortis based on its 16S rDNA sequence and key characteristics as compared with those of authentic cultures of B. vallismortis(KACC 12149) and B. mojavensis(KACC 12096). The strain showed broad spectrum of antibiotic activity in vitro test, as revealed in its strong inhibitory activity to the genera Phytophthora, Collectotrichum, Botrytis and Fusarium, but not to Rhizoctonia and Magnaporthe. In pot experiments, infection rate of hot pepper in the non-treated pots was about 89%, while it was only 29% in the pots treated with 1A strain. The result indicated B. vallismortis 1A is a potential biocontrol agent for phytophthora blight of hot pepper

• Research in Plant Disease
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• v.19 no.3
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• pp.183-187
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• 2013

Barley kernel discoloration (KD) leads to substantial loss in value through downgrading and discounting of malting barley. The objective of this research is to investigate fungal distribution and varieties resistance to KD in Korean two-rowed barley. Several fungal organisms including Alternaria spp., Fusarium spp., Aspergillus spp., Epicoccum spp. and Rhizopus spp. were isolated from Korean two-rowed barley representing KD. The symptoms of KD were brown and black discolorations of the lemma and palea. The most frequently detected fungal species was Alternaria spp. which exhibited 69.1% and 72.2% in 2011 and 2012, respectively. Epicoccum spp., Fusarium spp., and Aspergillus spp. were also detected. Fusarium spp., primary pathogen of barley head blight, were rarely occurred in the 2011 and their occurrence increased to 4.7% in 2012. Twenty cultivars of Korean two-rowed barely were evaluated to KD. The average percentage of KD was 8.0-36.0% in 2011 and 5.2-36.6% in 2012. Two cultivars ('Sacheon 6' and 'Dajinbori') showed KD of 6.2% to 8.8% and determined resistant, however 'Samdobori' and 'Daeyeongbori' demonstrating KD of 22.2-36.6% were highly susceptible. 'Jinyangbori', 'Danwonbori', 'Sinhobori' and 'Kwangmaegbori' showing KD of less than 15% were moderately resistant cultivar.

• The Plant Pathology Journal
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• v.18 no.5
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• pp.293-299
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• 2002

A survey of Fusarium wilt of perilla was conducted in 12 locations in Korea from 1999 to 2001. The disease occurred in 74 out of 187 fields in the 12 locations surveyed, and incidence of the disease reached up to 30% at its maximum in some perilla fields in Seosan and Dangjin. Incidence of the disease in the other locations ranged from 0.2 to 20%. A total of 327 isolates of Fusarium spp. were obtained from stems and roots of the diseased perilla plants. The isolates were identified based on their morphological characteristics. Out of the 327 isolates of Fusarium, 277 isolates from 12 locations were identified as F. oxysporum, 11 isolates from three locations as F. solani,17 isolates from two locations as F. equiseti, 4 isolates from one location as F. avenaceum and 6 isolates from one location as F. subglutinans. The other 12 isolates of Fusarium from four locations were unidentified. Twelve isolates of F. oxysporum and two isolates each of the other Fusarium spp. were tested for their pathogenicity to five cultivars of perilla. Seven isolates of F. oxysporum were strongly pathogenic to some perilla cultivars, but the other five isolates were weakly or not pathogenic. One isolate of F. solani was strongly pathogenic to all the perilla cultivars tested, but another isolate was not pathogenic. All the isolates of F. equiseti, F. avenaceum, and F. Subglutinans tested were not pathogenic to any of the perilla cultivars tested. Symptoms on the perilla plants induced by artificial inoculation with strongly pathogenic isolates of F. oxysporum and F. solani appeared as wilt, stem blight, and root yet, which were similar to those observed in the fields. The isolates which induced symptoms by artificial inoculation were re-isolated from the lesions of the perilla plants inoculated. All the isolates of F. oxysporum tested were not pathogenic to eight other crops inoculated. Results of this study reveal that F. oxysporum is the main pathogen of perilla wilt and that it is host specific to perilla. forma specialis of F. oxysporum causing wilt of perilla is proposed as perillae.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1001-1010
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• 2005

Bacillus megaterium KL39, an antibiotic-producing plant growth promoting rhizobacterium (PGPR), was selected from soil. The antifungal antibiotic, denoted KL39, was purified from culture filtrate by column chromatography using Dion HP-20, Silica gel, Sephadex LH-20, and prep-HPLC. Thin layer chromatography, employing the solvent system of ethanol:ammonia:water=8:1:1, showed the $R_{f}$. value of 0.32. The antibiotic KL39 showed a negative reaction with ninhydrin solution, positive with iodine vapor, and also positive with Ehrlich reagent. It was soluble in methanol, ethanol, butanol, and acetonitrile, but insoluble in chloroform, toluene, hexane, ethyl ether, or acetone. Its UV spectrum had the maximum absorption at 208 nm. Amino acid composition, FAB-mass, $^{1}H-NMR,\;^{13}C-NMR$, and atomic analyses showed that the antibiotic KL39 (MW=1,071) has a structure very similar to iturin E. The antibiotic KL39 has a broad antifungal spectrum against a variety of plant pathogenic fungi including Rhizoctonia solani, Pyricularia oryzae, Monilinia froeticola, Botrytis cinenea, Altenaria kikuchiana, Fusarium oxysporum, and F. solani. An MIC value of $10\;{\mu}g/ml$ was determined for Phytophthora capsici. Macromolecular incorporation studies with P. capsici using radioactive [$^{3}H-adenine$] as the precursor, indicated that the antibiotic KL39 strongly inhibits the DNA biosynthesis of the fungal cell. Microscopic observation of the antifungal action showed abnormal hyphal swelling of P. capsici. The purified antibiotic KL39 was very effective for the biocontrol of in vivo Phytophthora-blight disease of pepper.

• Microbiology and Biotechnology Letters
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• v.32 no.4
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• pp.312-316
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• 2004

In oder to select the powerful rhizophere-dorminatable biocontrol agent, we had isolated an indigenous antagonistic bacterium which produced antibiotic and siderophore from a disease suppressive local field soil of Gyungsan, Korea. And we could select the Pseudomosp. 4059 which can strongly antagonize against Fusarium oxysporum and Phytophthora capsici by two kinds of antifungal mechanism that can be caused by the antibiotic of Phenazin, a siderophore and a auxin like subThe selected strain was identified as Pseudomonas fluorescens (biotype A) 4059 by biochemical tests, API $\textregistered$ test, MicroLog TM system and 16S rDNA analysis. The selected antagonistic microorganism, Pseudomosp. 4059 had an antifungal mechanism of antifungal antibiotic and sidrophore. And we were confirmed the antagonistic activity of P fluorescens 4059 with in vitro antifungal test against Phytophthora capsici and in vivo by red-pepper.

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.27-27
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• 2016

The ascomycete fungus Fusarium graminearum is the most common pathogen of Fusarium head blight (FHB), a devastating disease for major cereal crops worldwide. FHB causes significant crop losses by reducing grain yield and quality as well as contaminating cereals with trichothecenes and zearalenone (ZEA) that pose a serious threat to animal health and food safety. ZEA is a causative agent of hyperestrogenic syndrome in mammals and can result in reproductive disorders in farm animals. In F. graminearum, the ZEA biosynthetic cluster is composed of four genes, PKS4, PKS13, ZEB1, and ZEB2, which encode a reducing polyketide synthase, a nonreducing polyketide synthase, an isoamyl alcohol oxidase, and a transcription factor, respectively. Although it is known that ZEB2 primarily acts as a regulator of ZEA biosynthetic cluster genes, the mechanism underlying this regulation remains undetermined. In this study, two isoforms (ZEB2L and ZEB2S) from the ZEB2 gene in F. graminearum were characterized. It was revealed that ZEB2L contains a basic leucine zipper (bZIP) DNA-binding domain at the N-terminus, whereas ZEB2S is an N-terminally truncated form of ZEB2L that lacks the bZIP domain. Interestingly, ZEA triggered the induction of both ZEB2L and ZEB2S transcription. In ZEA producing condition, the expression of ZEB2S transcripts via alternative promoter usage was directly or indirectly initiated by ZEA. Physical interaction between ZEB2L and ZEB2L as well as between ZEB2L and ZEB2S was observed in the nucleus. The ZEB2S-ZEB2S interaction was detected in both the cytosol and the nucleus. ZEB2L-ZEB2L oligomers activated ZEA biosynthetic cluster genes, including ZEB2L. ZEB2S inhibited ZEB2L transcription by forming ZEB2L-ZEB2S heterodimers, which reduced the DNA-binding activity of ZEB2L. This study provides insight into the autoregulation of ZEB2 expression by alternative promoter usage and a feedback loop during ZEA production.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.19-26
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• 2000

In order to select potent bioactive isolates, 70 Fusarium isolates obtained from soil and 21 plant species were screened by antifungal, insecticidal, herbicidal, and duckweed bioassays after culturing in potato dextrose broth and rice solid media. Eight (11.4%) of the 70 liquid broth cultures showed disease-controlling activities more than 80% against at least one of the 6 plant diseases tested. Fusarium sp. FO-68 isolate exhibited the most potent antifungal activity; it controlled rice blast, wheat leaf rust, and barley powdery mildew with control values more than 95%. Out of 70 solid cultures, 21 (30.0%) controlled at least one plant disease more than 80% and F. equiseti FO-68 isolate showed disease-controlling activities more than 95% against 3 plant diseases such as rice blast, tomato late blight, and wheat leaf rust. As for tile insecticidal activities, 2 liquid and 1 solid cultures showed potent insecticidal activities against pest insects more than 80%, Liquid cultures of F. oxysporum FO-61 and Fusarium sp. FO-80 isolates exhibited insecticidal activities more than 80% against green peach aphid and diamondback moth, respectively. The solid culture of Fusarium sp. FO-510 isolate had 80% insecticidal activity against green peach aphid. However, none of liquid and solid cultures of the 70 Fusarium isolates showed potent herbicidal activities against 10 upland weeds. As the results of duckweed assay, 3 liquid cultures showed 70% growth inhibitory activity at concentrations less than 1.25% of culture supernatants and 9 solid cultures had a potent inhibitory activity against duckweed growth. On the other hand, there was a significant correlation between antifungal activities and herbicidal activities against duckweed of both liquid and solid cultures of tile 70 Fusarium isolates.

• Research in Plant Disease
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• v.26 no.4
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• pp.250-255
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• 2020

In order to find if a ferulic acid (FA) can be used as a selection index in cereal breeding for resistance to head blight and mycotoxin production, we analyzed FA in the grains of 80 cultivars of barley, rice, and wheat. FA content ranged 1.66-2.77 mg/g in barley (n=20), 0.56-1.53 mg/g in wheat (n=40), and 0.91-2.13 mg/g in rice (n=20). Among these, 7 cultivars each of barley and wheat with different FA content were tested for head blight and mycotoxin production by 2 Fusarium graminearum and 2 F. asiaticum strains. Mean pathogenicity of the wheat cultivars was significantly less than that of barley with higher FA and among wheat cultivars, there was no correlation between FA content and pathogenicity. Mycotoxin production was also lower in the wheat than in the barley as pathogenicity. However, pathogenicity and toxins produced by F. asiaticum were negatively correlated with FA content in barley. These results indicate that FA is not a resistance factor to head blight by F. asiaticum and F. graminearum or its mycotoxin production in barley and wheat.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.10b
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• pp.246-247
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• 2005