• Plant Disease and Agriculture
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• v.5 no.2
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• pp.111-114
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• 1999

A bacterial disease of rice plant that rotted the sheath to brown was found in rice plants at Tanbuk Uisong Kyungbuk in June 1999, When the bacterial isolates from the diseased rice plants were inoculated to health plant by the artificial needle prick method the same symptoms were examined. According to its characteristics and pathogenicity on the his plant the causal bacterium was identified as Burkholderia glumae which is known as the pathogen of bacterial grain rot of rice.

• The Korean Journal of Mycology
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• v.10 no.4
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• pp.177-180
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• 1982

Gaeumannomyces graminis var. tritici was first isolated from rice in 1981. Sheath rot of rice seedling in box culture for machine transplanting was produced by artificial inoculation of the causal organism. Especially sheath rot was developed from crown to leaf sheath above water level. Perithecia were usually formed in dead leaf sheaths and in PDA culture. They were black, globose, and immersed with obliquely erumpent neck. Asci were unitunicate with an apical ring and contained 8 spores. Ascospores were hyline, slender, $80{\sim}140\;um$ in length. Each spore showed $3{\sim}4\;septa.$ Based on morphological and cultura characteristics, the isolate from seeds was identified as Gaeumannomyces graminis (Sacc.) Arx & Olivier tritici J. Walker.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.295-301
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• 2010

Sheath rot and dry rot disease caused by Pseudomonas marginalis and Fusarium oxysporum were serious problems in garlic farmland. In this study, total of 160 indigenous antagonistic bacteria were isolated from 16 farmlands in Yeongcheon, Korea. Among these, 15 strains were able to inhibited P. marginalis and F. oxysporum. The 16s rDNA genes of the selected 15 strains were amplified and sequenced. The strains has strong antagonistic ability against garlic pathogens was achieved Bacillus subtilis YC82, B. vallismortis YC84, B. amyloliquefaciens YC240. The selected 3 strains tested for investigation of antifungal mechanisms further analyses; 3 strains of these validated for production of siderophore, ${\beta}$-glucanase and chitinase using CAS (chrome azurol S) blue agar, CMC-congo red agar and DNS method. The 3 strains were able to utilized insoluble phosphate as dertermined by vanado-molybdate method. The 3 strains verified for production of auxin and gibberellic acid using Salkowski test and holdbrook test. Also, 3 strains showed stimulation germination, stem growth promoting activity on the in vivo test. The 3 strains were able to effectively suppress P. marginalis and F. oxysporum causing sheath rot and dry rot diseases on the in vivo pot test.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.61.2-61
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• 1999

• Korean journal of applied entomology
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• v.14 no.1 s.22
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• pp.23-27
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• 1975

Occurrence of sheath rot rice caused by Acrocylindrium oryzae on indica varieties, IR lines and IR varieties was light to moderate in the field, whereas generally none of the recommended japonica varieties showed the disease. In general, percentage infection in the field agreed with that obtained from seed inoculation tests made in the laboratory. Culture filtrates of the fungus inhibited the sprouting of seeds of rice, barley, wheat, rye and rape. A new variety, Tongil obtained from a hybrid between japonica and indica was inhibited significantly more than was Jinheung. Conidial germination of Pyricularia oryzae was inhibited by the filtrate while no inhibitory effects were found on conidia of Cochliobolus miyabeanus.

• The Korean Journal of Mycology
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• v.47 no.3
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• pp.259-269
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• 2019

Brown spot and sheath rot of rice are caused by fungal pathogens such as Curvularia lunata, Cochliobolus miyabeanus, and Sarocladium oryzae, and cause losses such as reduced rice yield and quality, which is an enormous problem with serious long-term effects. To search biological control agents of phytopathogenic fungi, five kinds of useful Bacillus-like isolates which are excellent in extracellular enzyme activity and produce siderophore were selected from paddy soil of Sunchang in Korea. The selected isolates were tested for excellent antifungal activity against three of the phytopathogenic fungi that frequently occur in rice, and JSRB 177 strain had the most excellent antifungal activity. Based on the experimental results, JSRB 177 is finally selected as a candidate for biological control and identified to Bacillus subtilis through 16S rRNA sequence analysis. In addition, physiological characteristics of JSRB 177 confirmed by analysis of carbohydrate fermentation patterns and enzyme production ability. Based on the above results, JSRB 177 is expected to be used as a biological control agent for the rice pathogenic fungi. In the future, further studies related to industrialization such as port test and establishment of mass production process are needed.

• The Plant Pathology Journal
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• v.28 no.3
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• pp.331-331
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• 2012

• Research in Plant Disease
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• v.12 no.2
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• pp.69-74
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• 2006

Basal rot of freesia caused by a Sclerotium sp. occurred at Incheon areas. Incidence of the disease reached up to 45% and averaged 17.0% in the fields. Typical symptoms consisted of sheath dry and leaf blight due to rots on basal leaves. The causal fungus was identified as Sclerotium sp. based on following mycological characteristics. The fungus formed sclerotia on cultural media and plant tissues, but did not produce asexual spores. On cultural medium, aerial mycelia of the fungus changed color from white to clay with cultural age and smelled musty odor. Numerous irregular and elliptical black microsclerotia of the fungus were formed on potato dextrose agar (PDA) after 5 days of incubation at $25^{\circ}C$ and sized $115{\sim}200{\times}95{\sim}150 (av. 145{\sim}126.5){\mu}m$. The fungus grew at $10{\sim}32^{\circ}C$ and $pH 4.0{\sim}8.5$. However, the optimal temperature and pH for mycelial growth of the fungus were $24^{\circ}C$ and 5.5 respectively. The isolate showed present pathogenicity to not only freesia but gladiolus in the pathogenicity test, and the symptoms were similar to those observed in the fields. Basal rot of freesia caused by Sclerotium sp. is firstly reported in Korea.

• The Plant Pathology Journal
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• v.29 no.3
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• pp.249-259
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• 2013

Burkholderia glumae causes rice grain rot and sheath rot by producing toxoflavin, the expression of which is regulated by quorum sensing (QS). The QS systems of B. glumae rely on N-octanoyl homoserine lactone, synthesized by TofI and its cognate receptor TofR, to activate the genes for toxoflavin biosynthesis and an IclR-type transcriptional regulator gene, qsmR. To understand genome-wide transcriptional profiling of QS signaling, we employed RNAseq of the wild-type B. glumae BGR1 with QS-defective mutant, BGS2 (BGR1 tofI::${\Omega}$) and QS-dependent transcriptional regulator mutant, BGS9 (BGR1 qsmR::${\Omega}$). A comparison of gene expression profiling among the wild-type BGR1 and the two mutants before and after QS onset as well as gene ontology (GO) enrichment analysis from differential expressed genes (DEGs) revealed that genes involved in motility were highly enriched in TofI-dependent DEGs, whereas genes for transport and DNA polymerase were highly enriched in QsmR-dependent DEGs. Further, a combination of pathways with these DEGs and phenotype analysis of mutants pointed to a couple of metabolic processes, which are dependent on QS in B. glumae, that were directly or indirectly related with bacterial motility. The consistency of observed bacterial phenotypes with GOs or metabolic pathways in QS-regulated genes implied that integration RNAseq with GO enrichment or pathways would be useful to study bacterial physiology and phenotypes.

• Research in Plant Disease
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• v.8 no.1
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• pp.1-10
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• 2002

Climate in the year of 2001 could be summarized as severe drought from March to May, unusually high temperature in whole plant growth periods and clear weather condition especially in harvesting time of September and October without any typoons. In rice, major diseases such as leaf and panicle blast, bacterial blight, sheath blight and bacterial grain rot developed little due to unfavorable weather conditions, however, brown spot occurred severely due partly to the reduced use of N-fertilizer, Rice stripe virus infection was unusually high mainly in the west coast areas with four times more diseaseD area campared to the previous year, In pepper phytophthora blight was extremely severe in Cheonnam and Cheonbuk provinces, where had frequent rainfalls during growing period. Incidence of major diseases of tomato and cucumber in 2001 was relatively mild. In watermelon, penicillium fruit rot, one of the peculiar disease, spread over major production areas, whereas CGMMV, usually severe in every years was much reduced. Watermelon plants growing in open-fields were more severely diseased than those in plastic houses. Major diseases of chinese melon and strawberry occurred slightly and in particular, sudden wilt syndrome of chinese melon which was severe in 2000 showed mild infections in 2001. Incidence of white rot of garlic and onion was much lower unlike other years due mainly to spring drought and high temperature in the growing period. Infected area of potato bacterial wilt tended to increase in 2001 while fusarium wilt of sweetpotato was decreased. Apple diseases were generally mild, but powdery mildew of pear increased sharply. Barley scab was not severe as seen in other years.