• Journal of Microbiology and Biotechnology
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• 제21권12호
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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.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.164-164
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• 2017

High throughput transcriptome investigations of immunity in plants highlight the complexity of gene networks leading to incompatible interaction. To identify genes crucial to resistance against Xanthomonas oryzae pv oryzae, functional genetic analysis of selected differentially expressed genes from our microarray data set was carried out. A total of 13 overexpression vector constructs were made using 35S CaMV promoter which drive constitutive expression in rice. Most of the genes are developmentally expressed especially during maximum tillering stage and are commonly highly expressed in the leaves. When screened against Xoo strain K2, the transgenic plants displayed shorter lesion length compared with wild type Dongjin which indicates partial resistance. The levels of ROS continuously magnified after inoculation which indicates robust cellular sensing necessary to initiate cell death. Elevated transcripts levels of several defense-related genes at the downstream of defense signal network also corroborate the phenotype reaction of the transgenic plants. Moreover, expression assays revealed regulation of these genes by cross-communicating signal-transductions pathways mediated by salicylic and jasmonic acid. These collective findings revealed the key immune signaling conduits critical to mount full defense against Xoo.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1995년도 Proceedings of special lectures on Molecular Biological Approaches to Plant Disease National Agricultural Science and Technology Institute Suwon, Korea
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• pp.1-19
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• 1995

The plasmid pJEL 101 contains a highly repetitive element from the genome of Xanthomonas oryae pv. oryzae that has properties of an insertional element. The insertional nature of the element, hereto referred to as IS203, was confirmed by molecular analyses of the element and three related elements that were isolated from X. oryzae. The related sequences were isolated on the basis of transposition to the transposon-trapping vector pL3SAC and hybridization with pJEL101. The trapped elements (IS203a, IS203b, and IS203c) were each composed of 1,055 base pairs with 25 base terminal inverted repeats. The elements caused a three base pair target site duplication at the site of insertion in the sacRB gene. The sequence of pJEL 101 has 96% base pair identity with IS203a and 99% identity with IS203a and IS203c but lacks three nucleotides of the consensus left terminal repeat. IS203b has the same DNA sequences as IS203c but is inserted ito the sacRB gene in the opposite orientation. The longest open reading frame of IS203a could code for a protein of 318 amino acids and molecular weight of 37, 151. A search of the Genbank database revealed that IS203 has 51% identity with 909 nucleotides of IS4551 from Escherichia coli. The predicted protein of ORF1 has 40% and 30% amino acid identity to the ORF1 of Tn4551 and the transposase of IS30, respectively.

• The Plant Pathology Journal
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• 제26권4호
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• pp.417-420
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• 2010

The expression of HR-like lesion inducing gene of Oryza sativa (OsHRL) was slightly increased by Xanthomonas oryzae pv. oryzae (Xoo) infection. Transgenic rice plants over-expressing OsHRL gene were challenged with Xoo and the development of disease symptoms were examined to investigate the effect of OsHRL gene expression on plant defense responses. The over-expression of OsHRL increased disease resistance against Xoo compared with wild type plants.

• The Plant Pathology Journal
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• 제38권5호
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• pp.490-502
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• 2022

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) disease in rice (Oryza sativa L.) and it is among the most destructive pathogen responsible for severe yield losses. Potential bacterial biocontrol agents (BCAs) with plant growth promotion (PGP) abilities can be applied to better manage the BLB disease and increase crop yield, compared to current conventional practices. Thus, this study aimed to isolate, screen, and identify potential BCAs with PGP abilities. Isolation of the BCAs was performed from internal plant tissues and rhizosphere soil of healthy and Xoo-infected rice. A total of 18 bacterial strains were successfully screened for in vitro antagonistic ability against Xoo, siderophore production and PGP potentials. Among the bacterial strains, 3 endophytes, Bacillus sp. strain USML8, Bacillus sp. strain USML9, and Bacillus sp. strain USMR1 which were isolated from diseased plants harbored the BCA traits and significantly reduced leaf blight severity of rice. Simultaneously, the endophytic BCAs also possessed plant growth promoting traits and were able to enhance rice growth. Application of the selected endophytes (BCAs-PGP) at the early growth stage of rice exhibited potential in suppressing BLB disease and promoting rice growth.

• 한국국제농업개발학회지
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• 제23권5호
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• pp.503-506
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• 2011

우리나라 재래종벼 6품종의 벼 흰잎마름병 저항성 유전자를 동정하고자 저항성 유전자 Xa1를 갖는 IR-BB 101과의 교배 조합을 양성하고 일본균주 IA(T7174)를 접종한 결과 청군벼의 벼 흰잎마름병 저항성 유전자는 Xa1 이었고, 육성재래, 아국도, 흑피 및 이천7일찰은 Xa1 및 다른 우성유전자 1개를 보유하였으며, 긴까락샤레는 Xa1 및 다른 우성유전자 2개를 갖고 있었고 이 중 2개는 저항성 발현에 보족적으로 작용하는 것으로 추정되었다.

• Biodesign
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• 제7권2호
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• pp.35-37
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• 2019

Xanthomonas oryzae pv. oryzae (Xoo) is a plant pathogen, which causes a bacterial blight of rice. The bacterial blight is one of the most devastating diseases of rice in most of the rice growing countries and there is no effective pesticide against bacterial blight. The β-ketoacyl-acyl carrier protein synthase III (FabH) plays a key role in fatty acid synthesis (FAS) and is a promising drug target for the development of antibacterial agents. Xoo0878 gene, a fabH gene, from Xoo was cloned and its gene product Xoo0878 was expressed, purified and crystallized. Xoo0878 crystal diffracted to 2.1Å resolution and belonged to the triclinic space group P1, with unit-cell parameters a = 57.3Å, b = 64.7Å, c = 104.2Å and α = 81.6°, β = 84.7°, γ = 74.4°. There are four monomers in the asymmetric unit, with a corresponding crystal volume per protein weight of 2.65 ų Da^-1 and a solvent content of 53.6%. Xoo0878 structure will be useful to develop new antibacterial agents against Xoo.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.740-747
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• 2014

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

• The Plant Pathology Journal
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• 제32권6호
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• pp.575-579
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• 2016

Burkholderia glumae (bacterial grain rot), Xanthomonas oryzae pv. oryzae (bacterial leaf blight), and Acidovorax avenae subsp. avenae (bacterial brown stripe) are major seedborne pathogens of rice. Based on the 16S and 23S rDNA sequences for A. avenae subsp. avenae and B. glumae, and transposase A gene sequence for X. oryzae pv. oryzae, three sets of primers had been designed to produce 402 bp for B. glumae, 490 bp for X. oryzae, and 290 bp for A. avenae subsp. avenae with the $63^{\circ}C$ as an optimum annealing temperature. Samples collected from naturally infected fields were detected with two bacteria, B. glumae and A. avenae subsp. avenae but X. oryzae pv. oryzae was not detected. This assay can be used to identify pathogens directly from infected seeds, and will be an effective tool for the identification of the three pathogens in rice plants.

• 한국식물병리학회지
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• 제2권2호
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• pp.102-106
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• 1986

1980년부터 1984년까지 호남지역에서 분리한 719균주를 새로운 판별방법에 의해 균형을 분류한 결과 $K_1$형이 466균주($64.8\%$), $K_2$형이 116균주($16.1\%$), $K_3$형이 130균주($18.1\%$), $K_4$형이 7균주($1.0\%$)였으나, $K_5$형은 전혀 분리되지 않았다. $K_1,\;K_2$형과 $K_3$형은 대부분의 지역에서 분포되었으며 $K_4$형은 남서해안지역인 해남, 광양, 강진, 완도, 익산, 부안에서 분리되었다. 이병성 품종인 밀양23호, 낙동벼 등에서는 모든 균형이 분리되었으나 대부분이 $K_1$형이었고, $K_3$형이나 $K_4$형은 저항성 품종인 풍산벼, 백양벼, 삼강벼, 밀양 30호 등에서 분리비율이 높았다.