• Korean Journal Plant Pathology
• /
• v.12 no.1
• /
• pp.11-20
• /
• 1996

한 쌍의 R16-1과 R23-2R primer를 이용한 PCR에 의해 증폭된 16S와 23S rDNA 사이의 rDNA spacer 부위의 다형성들이 Pseudomonas avenae, P. glumae, P. fuscovaginae, P. syringae pv. syrngae, Xanthomonas oryzae pv. oryzae, X. oryzae, Xanthomonas herbicola 등 벼 종자전염성 51개 균주의 구분을 위하여 적용되었다. 증폭산물은 820∼950bp의 크기였으며, 각각의 종에 특이적이었고 구분이 가능하였다. Pseudomonas species의 증폭산물은 P. avenae는 950bp, P. glumae는 850bp, P. fuscovaginae는 770pb 및 P. syringae pv. syringae는 1,240, 1,100 및 820bp로 특이적이었다. P. avenae와 P. glumae의 국내균주들은 다형성에 있어 종내 변이는 없었다. X. oryzae pv. oryzae의 860bp와 X. oryzae pv. oryzicola의 890, 440 및 370bp의 이차산물에서 Xanthomonas species의 종내에서 균주에 관련없이 단일화된 다형성을 보였다. CXO 211을 제외한 모든 국내 균주는 a형에 속한 반면 하나의 국내 균주를 포함하여 4개 균주는 b형이었다. E. herbicola의 spacer 부위 증폭은 여러 개의 band를 보였으며, 증폭상은 각각 동일하였고, strain간의 종내 변이는 없었다. 본 실험 결과에 의하여 16S와 23S rDNAdp R16-1과 R23-2R primer를 이용하여 PCR 증폭된 spacer 다형성의 구별은 종자전염성 세균의 신속한 구별에 이용될 수 있을것이다.

• Research in Plant Disease
• /
• v.14 no.3
• /
• pp.165-170
• /
• 2008

One hundred and three isolates of Xanthomonas oryzae pv. oryzae in Korea were evaluated for their virulence on four near-isogenic lines (NILs) containing a single resistance gene, and Korean differential varieties. The resistant gene backgrounds of Cheongcheongbyeo, Pungsanbyeo, Hangangchalbyeo, Milyang42 were not completely understood and they were not suited for the classification of X. oryzae pv. oryzae. Four NILs, IRBB101, IRBB103, IRBB105, and IRBB107 were difference for characterizing races of X. oryzae pv. oryzae because they have a single resistance gene. These NILs may be useful differential set in examining pathogenic races of X. oryzae pv. oryzae in Korea. Based on the virulence of 103 isolates to new differential varieties, they were classified into 3 races.

• The Plant Pathology Journal
• /
• v.20 no.3
• /
• pp.229-233
• /
• 2004

The bacterial leaf blight, which is caused by Xantho-monas oryzae pv. oryzae, is the most damaging and intractable disease of rice. To identify the genes involved in the virulence mechanism of transposon TnS complex, which possesses a linearized transposon and transposase, was successfully introduced into X. oryzae pv. oryzae by electroporation. The transposon mutants were selected and confirm the presence of transposition in X. oryzae pv. oryzae by the PCR amplification of transposon fragments and the Southern hybridization using these mutants. Furthermore, transposon insertion sites in the mutant bacterial chromosome were deter-mined by direct genomic DNA sequencing using transposon-specific primers with ABI 3100 Genetic Analyzer. Efficiency of transposition was influenced mostly by the competence status of X. oryzae pv. oryzae cells and the conditions of electroporation. These results indicated that the insertion mutagenesis strategy could be applied to define function of uncharacterized genes in X. oryzae pv. oryzae.

• Molecules and Cells
• /
• v.42 no.2
• /
• pp.166-174
• /
• 2019

Bacterial species in the genus Xanthomonas infect virtually all crop plants. Although many genes involved in Xanthomonas virulence have been identified through molecular and cellular studies, the elucidation of virulence-associated regulatory circuits is still far from complete. Functional gene networks have proven useful in generating hypotheses for genetic factors of biological processes in various species. Here, we present a genome-scale co-functional network of Xanthomonas oryze pv. oryzae (Xoo) genes, XooNet (www.inetbio.org/xoonet/), constructed by integrating heterogeneous types of genomics data derived from Xoo and other bacterial species. XooNet contains 106,000 functional links, which cover approximately 83% of the coding genome. XooNet is highly predictive for diverse biological processes in Xoo and can accurately reconstruct cellular pathways regulated by two-component signaling transduction systems (TCS). XooNet will be a useful in silico research platform for genetic dissection of virulence pathways in Xoo.

• Journal of Applied Biological Chemistry
• /
• v.51 no.3
• /
• pp.95-101
• /
• 2008

The gene encoding a putative esterase of Xanthomonas oryzae pv. oryzae was cloned using PCR technique. The gene was expressed with His6 tag in E. coli. One-step purification of the recombinant esterase with Ni-NTA resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 30 kDa, as expected, therefore the enzyme was a mononer. The enzyme was the most active toward p-nitrophenyl (p-NP) acetate and p-NP-butyrate to a lesser extent. However, the enzyme could not hydrolyze p-NP-myristate, palmitate, and stearate. Therefore, the enzyme is considered as an esterase, very different from lipase. The purified esterase had optimal pH at around 8.0 and was stable in a broad range of pH values. The optimal temperature ranged from 30 to $40^{\circ}C$, and the residual activity observed after heat treatment at $55^{\circ}C$ for 20 min was 72 % of the initial activity. The activity was inhibited by the presence of copper and cobalt ions.

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

• Journal of Microbiology and Biotechnology
• /
• v.23 no.1
• /
• pp.22-28
• /
• 2013

Xo2276 is a putative transcription activator-like effector (TALE) in Xanthomonas oryzae pv. oryzae (Xoo). Xo2276 was expressed with a TAP-tag at the C-terminus in Xoo cells to enable quantitative analysis of protein expression and secretion. Nearly all TAP-tagged Xo2276 existed in an insoluble form; addition of rice leaf extracts from a Xoosusceptible rice cultivar, Milyang23, significantly stimulated secretion of TAP-tagged Xo2276 into the medium. In a T3SS-defective Xoo mutant strain, secretion of TAPtagged Xo2276 was blocked. Xo2276 is a Xoo ortholog of Xanthomonas campestris pv. vesicatoria (Xcv) AvrBs3 and contains a conserved DNA-binding domain (DBD), which includes 19.5 tandem repeats of 34 amino acids. Xo2276- DBD was expressed in E. coli and purified. Direct in vitro recognition of Xo2276-DBD on a putative target DNA sequence was confirmed using an electrophoretic mobility shift assay. This is the first study measuring the homologous expression and secretion of Xo2276 in vitro using rice leaf extract and its direct in vitro binding to the specific target DNA sequence.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.727-730
• /
• 2001

Various recombinant deletion mutants were constructed from cycloinulo - oligosaccharide fructanotransferase(CFTase) gene of Xanthomonas oryzae #5 . The mutants were expressed in Escherichia coli DH5${\alpha}$. We were able to obtain three recombinant proteins were purified, and examine their CFTase and hydrolyzing activity. N-terminal deletion mutant had both CFTase activity and hydrolyzing activity. however, in C-terminal and N,C-terminal deletion mutant disappeared CFTase activity, but hydrolyzing activity remained. From there results, it seems that the C-terminal region(amino acid $1173{\sim}1333$) is important for cyclization.

• The Plant Pathology Journal
• /
• v.28 no.4
• /
• pp.364-372
• /
• 2012

Xanthomonas oryzae pv. oryzae causing bacterial leaf blight disease in rice produces and secretes Hpa1 protein that belongs to harpin protein family. Previously it was reported that Hpa1 induced defense responses when it was produced in tobacco. In this study, we expressed hpa1 gene in rice and Arabidopsis to examine the effects of Hpa1 expression on disease resistance to both fungal and bacterial pathogens. Expression of hpa1 gene in rice enhanced disease resistance to both X. oryzae pv. oryzae and Magnaporthe grisea. Interestingly, individual transgenic rice plants could be divided into four groups, depending on responses to both pathogens. hpa1 expression in Arabidopsis also enhanced disease resistance to both Botrytis cineria and Xanthomonas campestris pv. campestris. To examine genes that are up-regulated in the transgenic rice plants after inoculation with X. oryzae pv. oryzae, known defense-related genes were assessed, and also microarray analysis with the Rice 5 K DNA chip was performed. Interestingly, expression of OsACS1 gene, which was found as the gene that showed the highest induction, was induced earlier and stronger than that in the wild type plant. These results indicate that hpa1 expression in the diverse plant species, including monocot and dicot, can enhance disease resistance to both fungal and bacterial plant pathogens.

• Research in Plant Disease
• /
• v.16 no.3
• /
• pp.224-231
• /
• 2010

Xanthomonas oryzae pv. oryzae, causal agent of bacterial leaf blight (BLB) of rice, had been collected and identified using Biolog and fatty acid analysis. Epidemics of BLB had been occurred all the times at several rice cultivating areas in Korea in 1999-2004. Most X. oryzae pv. oryzae isolated in 1999 and 2002 belonged to Korean race K1, but more than 50% of the pathogen isolated in 2003 belonged to Korean race K3. Especially, most pathogens isolated in Jeonnam and Joenbuk provinces belonged to Korean race K3. Inoculation test of near isogenic lines (NIL) of rice carrying single resistance genes against BLB showed that many isolates belonging to Korean race 1 reacted differently to diverse resistant monogenic lines of rice. Southern blot analysis also showed that the bacterial pathogens belonged to the same race had different numbers of avirulence genes. This results suggested that each Korean race type may respond to many resistance genes of rice. All the K3 races isolated in Jeonnam and Joenbuk provinces were able to cause disease on Xa3 monogenic lines of rice. Since most rice cultivars cultivated in Jeonnam and Jeonbuk were carrying Xa3 resistance genes, the bacterial pathogens isolated in Jeonnam and Jeonbuk were likely to develop to adapt to Xa3 resistance gene. Together with avirulence gene patterns of the bacterial isolates and the results of disease reaction of monogenic lines of rice to them, Korean X. oryzae pv. oryzae was classified into 19 pathotypes. This newly classified pathotypes should help the breeding of new resistance rice cultivars in Korea.