• Journal of Applied Biological Chemistry
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• v.59 no.2
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• pp.149-154
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• 2016

An endophytic bacterial strain was isolated from kimchi, a Korean traditional fermented Brassica campestris and identified as Bacillus subtilis MJMP2 based on the 16S rRNA sequence. This strain showed strong antagonistic activity against Xanthomonas oryzae pv. oryzae (Xoo) KACC10331, the pathogen of bacterial rice blight disease, as well as activity against some other rice phytopathogenic fungi. The active compound was purified through size-exclusion chromatography and preparative High-performance liquid chromatography. The molecular weight was determined as m/z 1043 by mass spectroscopy, which is identical to that of iturin A. Furthermore, a crude extract from the culture supernatant of Bacillus subtilis MJMP2 showed inhibitory activity against rice blight disease in both a rice leaf explant assay and a pot assay. The crude extract also enhanced the length of roots of Arabidopsis thaliana. These results suggest that the strain Bacillus subtilis MJMP2 could be used as a biological agent to control rice blight disease.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.32-32
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• 1974

• Proceedings of the Korean Society of Crop Science Conference
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• 1990.05a
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• pp.48-49
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• 1990

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1236-1242
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• 2011

Xanthomonas oryzae pv. oryzae (Xoo) is the most devastating pathogen to Oryza sativa and has been shown to cause bacterial blight. Two bioactive compounds showing antimicrobial activities against Xoo strain KACC 10331 were isolated from a Streptomyces bottropensis strain. The ethyl acetate extract was fractionated on a Sephadex LH-20 column, and then purified by preparative HPLC. The purified compounds were identified as bottromycin A2 and dunaimycin D3S by HR/MS and $^1H$ NMR analyses. The MIC value against Xoo and the lowest concentration still capable of suppressing rice bacterial blight were 2 ${\mu}g$/ml and 16 ${\mu}g$/ml for bottromycin A2, and 64 ${\mu}g$/ml and 0.06 ${\mu}g$/ml for dunaimycin D3S, respectively. These two compounds were shown to exert different bioactivities in vitro and in rice leaf explants.

• Korean journal of applied entomology
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• v.19 no.3 s.44
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• pp.156-162
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• 1980

The inheritance and varietal differences of resistance to bacterial leaf blight caused by Xanthomonas oryzae in rice were studied. Among eighteen cultivars used, 'IR2061-465-1-5-5', 'IR2061-552-6-9', 'IR 1561-228-9-3', ana 'Milyang42, were found to have a high level of resistance to the three isolates of X. oryzae at maximum tillering and flowering stage. Varietal differences in lesion development of the cultivars belonging to the same varietal group were clearly recognized. For the genetic study on bacterial leaf blight resistance, two rice breeding lines 'IR2061-465-1-5-5', 'IR1561-228-3-3' were crossed with susceptible cultivar 'Milyang 23'. The $F_1,F_2,\;and\;F_3$ progenies were evaluated at flowering stage using the bacterial isolate 'JN 7853'(II). Average lesion length of the $F_1$ plants of the crosses showed longer than that of resistant parents, and the frequency distribution of lesion length in the $F_2\;and\;F_3$ populations showed continuous variation.

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.938-945
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• 2016

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious threats to rice production. In this study, screening of rice for resistance to BLB was carried out at two different times and locations; that is, in a greenhouse during winter and in an open field during summer. The pathogenicity of Xoo race K1 was tested on 32 Korean rice cultivars. Inoculation was conducted at the maximum tillering stage, and the lesion length was measured after 14 days of inoculation. Five cultivars, Hanareum, Namcheon, Samgdeok, Samgang, and Yangjo, were found to be resistant in both the greenhouse and open-field screenings. Expression of the plant defense-related genes JAmyb, OsNPR1, OsPR1a, OsWRKY45, and OsPR10b was observed in resistant and susceptible cultivars by qRT-PCR. Among the five genes tested, only OsPR10b showed coherent expression with the phenotypes. Screening of resistance to Xoo in rice was more accurate when conducted in open fields in the summer cultivation period than in greenhouses in winter. The expression of plant defense-related genes after bacterial inoculation could give another perspective in elucidating defense mechanisms by using both resistant and susceptible individuals.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.138-138
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• 2017

Agriculture is the most primitive civilized Activities of mankind but also the propellant of civilization development. Because it is the most basic material goods source of mankind. Among these materials rice is one of the most important part of these, we call them the substance of survival. From the beginning of the agricultural activities to the present we have experienced three industrial revolutions and are experiencing the Fourth Industrial Revolution. With the development of science and technology makes the efficiency of agricultural production is higher and higher, but compared with the original we are facing the same problem: natural disasters; pests and diseases; now also face the depletion of resources, environmental degradation and other issues. Therefore, improve and cultivate new crop varieties to make it better resistance and more production for better develop modern agriculture. It's very helpful for human social development. And also it is the responsibility and task of modern molecular breeding. In this study, I used bacterial leaf blight to find a better resistance gene to improve the resistance of rice. Frist Cultivate k3 of bacterial leaf blight, than inoculation by leaf clipping method (Kauffman,1973) in CNDH and SNDH population at 40days after rice transplanting. Check the lesion length by inoculation plants at 14days after inoculation, and record data for QTL analysis program. Than I get 4 intervals in 3 different chromosomal regions. I found these defense genes in the 4 intervals. So I used NCBI Justbio, Rapdb, etc. to finding these genes in physical map, than design primer for map base cloning. At last these defense genes will be employed in further research for introduction of the gene to the parental plant and rice breeding for solving food crisis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.11-14
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• 1984

The inheritance of scent in rice leaf and its genetic association with base color, hull color and resistance to bacterial leaf blight were studied in F$_2$ population of two rice crosses, P-33-C-19 (scented)/Zhu-Lian-Ai and P-33-C-19/Kataktara DA2. The scent was identified by leaf analysis at tillering stage. The scented and non-scented plants segregated in the ratio of 1scented: 3non-scented showing that a recessive gene responsible for the expression of scentedness. The scentedness was independently segregated with base color. hull color and resistance to bacterial leaf blight.

• Microbiology and Biotechnology Letters
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• v.46 no.4
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• pp.346-359
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• 2018

Xanthomonas oryzae, a bacterial pathogen causing leaf blight disease (BLB) in rice, can cause widespread disease and has caused epidemics globally, resulting in severe crop losses of 50% in Asia. The pathogen is seed-borne and is transmitted through seeds. Thus, control of BLB requires the elimination of the pathogen from seeds. Concern about environment-friendly organic production has spurred improvements in a variety of biological disease control methods, including the use of bacteriophages, against bacterial plant pathogens. The present study explored the potential of bacteriophages isolated from diseased plant leaves and soil samples in killing the bacterial pathogen in rice seeds. Eight different phages were isolated and evaluated for their bacteriolytic activity against different pathogenic X. oryzae strains. Of these, a phage designated ${\varphi}XOF4$ killed all the pathogenic X. oryzae strains and showed the broadest host range. Transmission electron microscopy of ${\varphi}XOF4$ revealed it to be a tailed phage with an icosahedral head. The virus was assigned to the family Siphoviridae, order Caudovirales. Seedlings raised from the seeds treated with $1{\times}10^8pfu/ml$ of ${\varphi}XOF4$ phage displayed reduced incidence of BLB disease and complete bacterial growth inhibition. The findings indicate the potential of the ${\varphi}XOF4$ phage as a potential biological control agent against BLB disease in rice.

• 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.