• Journal of Microbiology and Biotechnology
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• v.7 no.2
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• pp.157-159
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• 1997

A 340-bp chitin synthase gene(CHS) fragment was cloned from the genomic DNA of Pyricularia oryzae using a PCR process with two primer DNAs corresponding to highly conserved sequences within fungal CHS genes. The entire DNA nucleotide sequences of the cloned DNA fragment were determined and analyzed. The amino acid sequences deduced from the nucleotide sequence of the amplified DNA fragment showed 86% homology to that of the Aspergillus fumigatus CHSE gene (9). Using this PCR-amplified DNA, about 2.3 kb of including the PCR fragment of CHSE gene was cloned from genomic library.

• The Plant Pathology Journal
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• v.24 no.2
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• pp.131-142
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• 2008

Magnaporthe oryzae, the causal agent of the rice blast disease, poses a worldwide threat to stable rice production. The large-scale functional characterization of genes controlling the pathogenicity of M. oryzae is currently under way, but little is known about heat shock protein 40 (Hsp40) function in the rice blast fungus or any other filamentous plant pathogen. We identified 25 genes encoding putative Hsp40s in the genome of M. oryzae using a bioinformatic approach, which we designated M. oryzae heat shock protein forty (MHF 1-25). To elucidate the roles of these genes, we characterized the functions of MHF16 and MHF21, which encode type ill and type n Hsp40 proteins, respectively. MHF16 and MHF21 expression was not significantly induced by heat shock, but it was down-regulated by cold shock. Knockout mutants of these genes $({\Delta}$mhf16 and ${\Delta}$mhf21) were viable, but conidiation was severely reduced. Moreover, sectoring was observed in the ${\Delta}mhf16$ mutant when it was grown on oatmeal agar medium. Conidial germination, appressorium formation, and pathogenicity in rice were not significantly affected in the mutants. The defects in conidiation and colony morphology were fully complemented by reintroduction of wild type MHF16 and MHF21 alleles, respectively. These data indicate that MHF16 and MHF21 play important roles in conidiation in the rice blast fungus.

• Research in Plant Disease
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• v.25 no.1
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• pp.1-7
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• 2019

The rice blast fungus, Magnaporthe oryzae, is one of the most economically important crop diseases. In addition, rice-M. oryzae interaction is a classical gene-for-gene host-pathogen system. Race variation in pathogen groups was proposed as the main mechanism for rapid break-down of resistance in newly introduced rice cultivars. These new pathogen race variations may be caused by changes in an avirulence gene, such as (i) point mutations, (ii) insertion of transposons, and (iii) frame shifts. The avirulence gene AVR-Pita1 is representative avirulence gene in which all of these mutations are reported. In this review, we present a useful information for avirulence gene AVR-Pita1 and its homologous genes AVR-Pita2 and AVR-Pita3. We also review examples that cause mutations in these evolutionarily significant genes.

• The Plant Pathology Journal
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• v.26 no.1
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• pp.37-48
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• 2010

This paper describes a web-based information system for plant disease forecast that was developed for crop growers in Gyeonggi-do, Korea. The system generates hourly or daily warnings at the spatial resolution of $240\;m{\times}240\;m$ based on weather data. The system consists of four components including weather data acquisition system, job process system, data storage system, and web service system. The spatial resolution of disease forecast is high enough to estimate daily or hourly infection risks of individual farms, so that farmers can use the forecast information practically in determining if and when fungicides are to be sprayed to control diseases. Currently, forecasting models for blast, sheath blight, and grain rot of rice, and scab and rust of pear are available for the system. As for the spatial interpolation of weather data, the interpolated temperature and relative humidity showed high accuracy as compared with the observed data at the same locations. However, the spatial interpolation of rainfall and leaf wetness events needs to be improved. For rice blast forecasting, 44.5% of infection warnings based on the observed weather data were correctly estimated when the disease forecast was made based on the interpolated weather data. The low accuracy in disease forecast based on the interpolated weather data was mainly due to the failure in estimating leaf wetness events.

• Korean journal of applied entomology
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• v.11 no.1
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• pp.41-43
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• 1972

1. In order to investigate the epidemic outbreak of rice blast disease on the resistant variety Kwankon in 1969, this investigation was undertaken as a basis for breeding resistant varieties. 2. The 16 isolates collected from Kyunggi area were inoculated at the 3-4 leaf stage on 12 Japanese differential varieties used for identifying races under greenhouse conditions. Out of 16 isolates 15 were identified as C race group and one as N race group. Of the 15 rates, nine were C-8, two were C-7 and two were C-1. Of the remaining two isolates, one was similar to C-1, and the other was similar to C-5. 3. It is concluded that the epidemic in the resistant variety 'Kwanok' was due to the occurrence of the C race group, which can infect the Chinese type varieties.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1513-1520
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• 2004

We investigate a series of synthesized ${\beta}$-methoxyacrylate analogues for their 3D QSAR & HQSAR against Magnaporthe grisea (Rice Blast Disease). We perform the three-dimensional Quantitative Structure-Activity Relationship (3D-QSAR) studies, using the comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) procedure. In addition, we carry out a two-dimensional Quantitative Structure-Activity Relationship (2D-QSAR) study, using the Hologram QSAR (HQSAR). We perform these studies, using 53 compounds as a training set and 10 compounds as a test set. The predictive QSAR models have conventional $r^2$ values of 0.955 at CoMFA, 0.917 at CoMSIA, and 0.910 at HQSAR respectively; similarly, we obtain cross-validated coefficient $q^2$ values of 0.822 at CoMFA, 0.763 at CoMSIA, and 0.816 at HQSAR, respectively. From these studies, the CoMFA model performs better than the CoMSIA model.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.1
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• pp.147-157
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• 2013

Rice is a main crop and rice field is the most important farmland in Korea. This study was conducted to propose the methodology assessing impact and vulnerability on rice production by climate change at the regional and national level in Korea. We evaluated a vulnerability of rice paddy according to the outbreak of a main disease and pest of a rice plant. As results, Jeju-do, Gyeongsangnam-do, and Jeollanam-do were more vulnerable area than others. In contrast, the southern central region including Gyeonggi-do was less vulnerable than others. The vulnerable index was significantly higher in 2050s (0.5589) than in present (0.3500). This result showed that the vulnerable to the disease and pest enlarge in the future. The adaptive capacity highly contributed to the vulnerability assessment index. The daily maximum temperature of June and the daily average temperature from May to August also contributed the climate exposure index. The area of occurring sheath blight, rice leaf blast and striped rice borer was related to the system sensitivity index. The ability of water supply (readjustment area of arable land per paddy field area) and rice production technique (rice yield per hectare) were the highly contributed variables to the adaption capacity index.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.31-31
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• 2022

Rice contains a wealth of genetic diversity, both within Oryza sativa and in related A-genome species. Decades of genetic research into this diversity have identified dozens of major genes contributing to a wide variety of important traits, including disease resistance, abiotic stress tolerance (drought, salinity, submergence, heat, cold etc.), grain quality, flowering date and maturity and plant architecture. Yet despite these opportunities, very few of the major genes and QTLs known have been successfully applied through rice breeding programs to produce sustained changes in farmer's fields. This presentation will briefly examine some of the factors limiting application of major genes in the mainstream breeding programs, and steps that have been taken to alleviate those limitations. As a result of these interventions, dozens of major genes that were previously unavailable to breeders are now being used confidently in the variety development process. Case studies will be discussed of genes critical for blast resistance worldwide, rice yellow mottle virus for Africa, and new validated QTLs for salinity tolerance.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.04a
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• pp.90.1-90.1
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• 2005

• Research in Plant Disease
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• v.18 no.1
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• pp.24-28
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• 2012

The rice diseases occurring on the transgenic rice plant carrying protox gene (CPPO06) was assessed and compared with other varieties of rice such as Dongjin, Chucheong, Ilpeum, and Onnuri in the fields located in Cheongwon of Chungbuk, Suwon of Gyeunggi, and Gwangju of Chonnam. In the field of Cheongwon, the diseases such as blast, leaf spot, sheath blight and Fusarium blight were observed. False smut were observed only in the field of Suwon, where the ratio of diseased plants was 0.28% in CPPO06 and 0.37% in Onnuri, respectively. In the field of Gwangju, leaf spot caused by Cochlioborus miyabeanus was the most severely occurring disease among rice diseases mentioned above. Fusarium blight occurred in all the 3 fields, which were more severe in CPPO06 plants treated with or without oxadiazon as the herbicide. Except for Fusarium blight, there was no significant difference in the rice diseases as blast, leaf spot, sheath blight and false smut between CPPO06 and other rice varieties.