• The Korean Journal of Mycology
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• v.25 no.4 s.83
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• pp.291-296
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• 1997

Diseased leaves of Job's tears were collected at six locations in Korea to isolate and identify the pathogen causing leaf blight. Conidia were brown, fusoid, and slightly curved. They were $25{\sim}46{\times}10{\sim}15\;{\mu}m$ in size, and had mostly 4 septa which were characteristic of pseudosepta. A few conidia had slightly protruding hila, whereas most had no hilum. Conidial germ tubes were produced mostly from both polar end cells (bipolar), and progressed in semiaxial direction. When seedlings of Job's tears were inoculated with conidia, long, spindle-shaped, and brown lesions were produced on leaves, and entire leaves became blighted 15 days later. Based on the aggressiveness in pathogenicity, the isolates could be divided into two groups. Considering the mycological characteristics and pathogenicity of the fungus, the pathogen causing leaf blight of Job's tears was determined to be Bipolaris coicis (Nisikado) Shoemaker.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.374.2-374
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• 2001

• The Plant Pathology Journal
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• v.17 no.6
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• pp.383.6-384
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• 2001

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.04a
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• pp.33.3-34
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• 1999

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.04a
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• pp.15.1-15
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• 1999

• Mycobiology
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• v.30 no.4
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• pp.233-239
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• 2002

The main aim of this study is to evaluate the efficiency of two biologically active compounds(Strom and F-760) in control of wheat root rot disease and its causal organisms. Fusarium graminearum, F. oxysporum, F. solani and Bipolaris sorokiniana were used as target organisms. In vitro, the two compounds showed fungicidal effect on all investigated pathogens resulted in suppression of radial growth and mycelial dry weight of them. Under greenhouse conditions, treatment of wheat grains with either Strom or F-760 before cultivation significantly reduced the percent of disease distribution as well as the mean disease rating of plants in both seedling and flowering stages. Fresh and dry weights of plants as well as water maintenance capacity were increased as the result of applying these compounds as seed dressing. Also data showed that the membrane stability of plants was injured as a result of infection with all investigated organisms, while this injury was alleviated when F-760 and Strom were applied. The $K^+$ efflux and the leakage of UV absorbing metabolites was stimulated with fungal infection. However, F-760 and Storm treatment partially retarded the stimulatory effect on leakage of $K^+$ and UV-absorbing metabolites of fungal infected plants. On the other side, the fungal infection had inhibitory effects on pigment fractions(chlorophyll a, b, and carotenoids) biosynthesis in wheat leaves. This retarding effect was partially or completely alleviated as the grains were treated with the applied compounds.

• The Plant Pathology Journal
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• v.34 no.4
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• pp.327-334
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• 2018

Northern corn leaf spot and southern corn leaf blight caused by Cochliobolus carbonum (anamorph, Bipolaris zeicola) and Cochliobolus heterostrophus (anamorph, Bipolaris maydis), respectively, are common maize diseases in Korea. Accurate detection of plant pathogens is necessary for effective disease management. Based on the polyketide synthase gene (PKS) of Cochliobolus carbonum and the nonribosomal peptide synthetase gene (NRPS) of Cochliobolus heterostrophus, primer pairs were designed for PCR to simultaneously detect the two fungal pathogens and were specific and sensitive enough to be used for duplex PCR analysis. This duplex PCR-based method was found to be effective for diagnosing simultaneous infections from the two Cochliobolus species that display similar morphological and mycological characteristics. With this method, it is possible to prevent infections in maize by detecting infected seeds or maize and discarding them. Besides saving time and effort, early diagnosis can help to prevent infections, establish comprehensive management systems, and secure healthy seeds.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2000.10a
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• pp.21.1-21
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• 2000

• The Plant Pathology Journal
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• v.32 no.1
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• pp.53-57
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• 2016

Major diseases in grafted cacti have been reported and Fusarium oxysporum, Bipolaris cactivora, Phytophthora spp. and Collectotrichum spp. are known as causal pathogens. These pathogens can lead to plant death after infection. Therefore, some European countries have quarantined imported cacti that are infected with specific fungal pathogens. Consequently, we developed PCR detection methods to identify four quarantined fungal pathogens and reduce export rejection rates of Korean grafted cacti. The pathogen specific primer sets F.oF-F.oR, B.CF-B.CR, P.nF-P.nR, and P.cF-P.CR were tested for F. oxysporum, B.cactivora, P. nicotinae, and P. cactorum, respectively. The F.oF-F.oR primer set was designed from the Fusarium ITS region; the B.CF-B.CR and P.nF-P.nR primers respectively from Bipolaris and Phytophthora ITS1; and the P.cF-P.CR primer set from the Ypt1protein gene region. The quarantine fungal pathogen primer pairs were amplified to the specific number of base pairs in each of the following fungal pathogens: 210-bp (F. oxysporum), 510-bp (B. cactivora), 313-bp (P. nicotinae), and 447-bp (P. cactorum). The detection limit for the mono- and multiplex PCR primer sets was 0.1 ng of template DNA under in vitro conditions. Therefore, each primer set successfully diagnosed contamination of quarantine pathogens in export grafted cacti. Consequently, our methodology is a viable tool to screen contamination of the fungal pathogen in exported grafted cacti.

• The Plant Pathology Journal
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• v.35 no.4
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• pp.287-300
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• 2019

Spot blotch caused by Bipolaris sorokiniana has spread to more than 9 million ha of wheat in the warm, humid areas of the Eastern Gangetic Plains (EGP) of South Asia and is a disease of major concern in other similar wheat growing regions worldwide. Differential lignin content in resistant and susceptible genotypes and its association with free radicals such as hydrogen peroxide ($H_2O_2$), superoxide ($O_2{^-}$) and hydroxyl radical ($OH^-$) were studied after inoculation under field conditions for two consecutive years. $H_2O_2$ significantly influenced lignin content in flag leaves, whereas there was a negative correlation among lignin and $H_2O_2$ to the Area Under Disease Progress Curve (AUDPC). The production of $H_2O_2$ was higher in the resistant genotypes than susceptible ones. The $O_2{^-}$ and $OH^-$ positively correlated with AUDPC but negatively with lignin content. This study illustrates that $H_2O_2$ has a vital role in prompting lignification and thereby resistance to spot blotch in wheat. We used cluster analysis to separate the resistant and susceptible genotypes by phenotypic and biochemical traits. $H_2O_2$ associated lignin production significantly reduced the number of appressoria and penetration pegs. We visualized the effect of lignin in disease resistance using differential histochemical staining of tissue from resistant and susceptible genotypes, which shows the variable accumulation of hydrogen peroxide and lignin around penetration sites.