• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.108.2-109
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• 2003

The Gyeonggi-do Agricultural Research and Extension Services has developed a web-site (www.epilove.com) in collaboration with EPINET to provide information on agricultural weather and rice disease and insect pest management in Gyeonggi-do. Weather information includes near real-time weather data monitored by automated weather stations (AWS) installed at rice paddy fields of 11 Agricultural Technology Centers (ATC) in Gyeonggi-do, and weekly weather forecast by Korea Meteorological Administration (KMA). Map images of hourly air temperature and rainfall are also generated at 309m x 309m resolution using hourly data obtained from AWS installed at 191 locations by KMA. Based on near real-time weather data from 11 ATC, hourly infection risks of rice blast, sheath blight, and bacterial grain rot for individual districts are estimated by disease forecasting models, BLAST, SHBLIGHT, and GRAINROT. Users can diagnose various diseases and insects of rice and find their information in detail by browsing thumbnail images of them. A database on agrochemicals is linked to the system for disease and insect diagnosis to help users search for appropriate agrochemicals to control diseases and insect pests.

• The Korean Journal of Mycology
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• v.23 no.3 s.74
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• pp.257-265
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• 1995

Morphological characteristics and pathogenicity of Rhizoctonia species causing blight diseases of turfgrasses were studied. The species were identified as Rhizoctonia cerealis Van der Hoeven, R. oryzae Ryker et Gooch, and R. solani $K{\ddot{u}hn}$ based on their morphological and cultural characteristics. Isolates of R. solani were assigned to anastomosis groups (AG) with cultural type 1 (1A), 2-2 (IIIB), and 2-2 (IV). R. cerealis, R. oryzae and R. solani induced sheath rot and foliar blight symptoms on creeping bentgrass (Agrostis palustris) and zoysiagrass (Zoysia japonica). Inoculation tests showed that disease severity with isolates of R. cerealis and R. oryzae were more serious to creeping bentgrass than zoysiagrass. AG 1(1A) isolates of R. solani were strongly pathogenic on creeping bentgrass, but moderate to zoysiagrass. AG 2-2 (III) isolates were moderately pathogenic to zoysiagrass, but weakly to creeping bentgrass. AG 2-2 (IV) isolates from zoysiagrass were moderately pathogenic to zoysiagrass, but weakly to creeping bentgrass.

• 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.

• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1609-1621
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• 2014

The plant pathogen Burkholderia gladioli, which has a broad host range that includes rice and onion, causes bacterial panicle blight and sheath rot. Based on the complete genome sequence of B. gladioli BSR3 isolated from infected rice sheaths, the genome of B. gladioli BSR3 contains the luxI/luxR family of genes. Members of this family encode N-acyl-homoserine lactone (AHL) quorum sensing (QS) signal synthase and the LuxR-family AHL signal receptor, which are similar to B. glumae BGR1. In B. glumae, QS has been shown to play pivotal roles in many bacterial behaviors. In this study, we compared the QS-dependent gene expression between B. gladioli BSR3 and a QS-defective B. gladioli BSR3 mutant in two different culture states (10 and 24 h after incubation, corresponding to an exponential phase and a stationary phase) using RNA sequencing (RNA-seq). RNA-seq analyses including gene ontology and pathway enrichment revealed that the B. gladioli BSR3 QS system regulates genes related to motility, toxin production, and oxalogenesis, which were previously reported in B. glumae. Moreover, the uncharacterized polyketide biosynthesis is activated by QS, which was not detected in B. glumae. Thus, we observed not only common QS-dependent genes between B. glumae BGR1 and B. gladioli BSR3, but also unique QS-dependent genes in B. gladioli BSR3.

• Research in Plant Disease
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• v.19 no.3
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• pp.177-182
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• 2013

Resvestrol has been known to inhibit bacterial and fungal growth in vitro, and can be accumulated in plant to concentrations necessary to inhibit microbial pathogens. Hence, stilbene synthase gene has been used to transform to synthesize resveratrol in heterologous plant species to enhance resistance against pathogens. In the present study, we investigated the antimicrobial activities of resveratrol and piceid to bacterial and fungal pathogens, which causing severe damages to rice plants. In addition, disease resistance was compared between transgenic rice varieties, Iksan 515 and Iksan 526 transformed with stlibene synthase gene and non-transgenic rice varieties, Dongjin and Nampyeong. Minimum inhibitory concentration of resveratrol for Burkolderia glumae was 437.5 ${\mu}M$, and the mycelial growth of Biplaris oryzae was slightly inhibited at concentration of 10 ${\mu}M$. However, other bacterial and fungal pathogens are not inhibited by resveratrol and piceid. The expression of the stilbene synthase gene in Iksan 515 and Iksan 526 did not significantly enhanced resistance against bacterial grain rot, bacterial leaf blight, sheath blight, and leaf blight. This study is the first report on the effect of resveratrol and piceid against pathogens of rice plant, and changes of disease resistance of transgenic rice plants transformed with stilbene synthase gene.

• The Plant Pathology Journal
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• v.33 no.5
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• pp.488-498
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• 2017

The aim of this study was to identify volatile and agardiffusible antifungal metabolites produced by Bacillus sp. G341 with strong antifungal activity against various phytopathogenic fungi. Strain G341 isolated from four-year-old roots of Korean ginseng with rot symptoms was identified as Bacillus velezensis based on 16S rDNA and gyrA sequences. Strain G341 inhibited mycelial growth of all phytopathogenic fungi tested. In vivo experiment results revealed that n-butanol extract of fermentation broth effectively controlled the development of rice sheath blight, tomato gray mold, tomato late blight, wheat leaf rust, barley powdery mildew, and red pepper anthracnose. Two antifungal compounds were isolated from strain G341 and identified as bacillomycin L and fengycin A by MS/MS analysis. Moreover, volatile compounds emitted from strain G341 were found to be able to inhibit mycelial growth of various phytopathogenic fungi. Based on volatile compound profiles of strain G341 obtained through headspace collection and analysis on GC-MS, dimethylsulfoxide, 1-butanol, and 3-hydroxy-2-butanone (acetoin) were identified. Taken together, these results suggest that B. valezensis G341 can be used as a biocontrol agent for various plant diseases caused by phytopathogenic fungi.

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.27-32
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• 2011

This study was carried out to investigate characteristics of new garlic cultivar 'Alkae' and to identify the effect of scape removal on bulb characteristics and growth of garlic cultivar 'Alkae' and 'Namdo'. Bolting time and harvesting time were earlier about 20 days in 'Alkae' than those in 'Namdo'. 'Alkae' was inferior to 'Namdo' in top growth as plant height, number of leaves, leaf area, SPAD value, diameter of leaf sheath, and so on. but root developing was better in 'Alkae'. Bulb weight of' Alkae' was 17% more than that of 'Namdo', harvested on proper time. The ratio of bulb weight over 40 g was almost double in 'Namdo' as 48% with 'Alkae' as 25%. Occurrence of bulb cracking was more considerable in 'Alkae' and the number of clove per bulb was 1.9 more in 'Alkae' than 'Namdo', but the ratio of bulb rot during storage was higher in 'Namdo' than 'Alkae'. In treatments of scape removal, SPAD value did not show any difference between two cultivars. Leaf dryness was earlier and harder than control and leaf area showed the same tendency as leaf dryness, and there were no significant differences among the methods of scape removal. The bulb weight and the ratio of bulb weight over 40 g at 50 days after the harvest of 'Alkae', 'Namdo' were more 10%, 12% and 27%, 44% in scape removal treatment than control. and there were no significant differences among the methods of scape removal. So, scape removal was very effective to increase large bulb production in the two garlic cultivals and the effect was higher in 'Namdo' than 'Alkae'. The ratio of bulb cracking and the occurrence of bulb rot were almost same in with the scape removal and non removal groups And also there were no significant differences among the methods of scape removal.