Oryzae Pv. Oryzae (oryzae + pv._oryzae)

Distribution by Scientific Domains

Kinds of Oryzae Pv. Oryzae

  • xanthomonas oryzae pv. oryzae


  • Selected Abstracts


    Status of Streptomycin Resistance Development in Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola in China and their Resistance Characters

    JOURNAL OF PHYTOPATHOLOGY, Issue 9 2010
    Ying Xu
    Abstract Rice leaves with bacterial blight or bacterial leaf streak symptoms were collected in southern China in 2007 and 2008. Five hundred and thirty-four single-colony isolates of Xanthomonas oryzae pv. oryzae and 827 single-colony isolates of Xanthomonas oryzae pv. oryzicola were obtained and tested on plates for sensitivity to streptomycin. Four strains (0.75%) of X. oryzae pv. oryzae isolated from the same county of Province Yunnan were resistant to streptomycin, and the resistance factor (the ratio of the mean median effective concentration inhibiting growth of resistant isolates to that of sensitive isolates) was approximately 226. The resistant isolate also showed streptomycin resistance in vivo. In addition to resistant isolates, isolates of less sensitivity were also present in the population of X. oryzae pv. oryzae from Province Yunnan. However, no isolates with decreased streptomycin-sensitivity were obtained from the population of X. oryzae pv. oryzicola. Mutations in the rpsL (encoding S12 protein) and rrs genes (encoding 16S rRNA) and the presence of the strA gene accounting for streptomycin resistance in other phytopathogens or animal and human pathogenic bacteria were examined on sensitive and resistant strains of X. oryzae pv. oryzae by polymerase chain reaction amplification and sequencing. Neither the presence of the strA gene nor mutations in the rpsL or rrs were found, suggesting that different resistance mechanisms are involved in the resistant isolates of X. oryzae pv. oryzae. [source]


    Analysis of Pathotypic and Genotypic Diversity of Xanthomonas oryzae pv. oryzae in China

    JOURNAL OF PHYTOPATHOLOGY, Issue 4 2009
    Gang Li
    Abstract Virulence analysis and restriction fragment length polymorphism (RFLP) were used to evaluated the population structure of Xanthomonas oryzae pv. oryzae (Xoo) from the main rice-growing region in China. The pathotype of Xoo was determined for 103 strains by inoculating 13 near-isogenic rice lines using IR24 as the recurrent parent. Sixty-one pathotypes was shared by these strains, on the basis of the consensus of three clustering statistics, and four clusters for pathotype were formed. Cluster 2 consists of strains with high molecular polymorphorism and many pathotypes that are either virulent to a majority of the 13 major resistance (R) genes or avirulent only to Xa21, and is geographically dispersed. The resistance gene Xa21 has broader resistance than others to the strains tested. A probe from a member of the avrBs3/pthA type III effector family, 1376 bp SphI-digested fragment, was used to screen the genomes of 52 strains tested. Four common bands were found in the DNA fingerprint pattern of Xoo, suggesting basic patterns of evolutionary relationship for members of avrBs3/pthA family and/or the pathogen. Each distinct RFLP banding pattern of each strain was considered as a haplotype; 42 haplotypes were revealed by the probe and divided into four lineages by the same statistics method. It was observed that some isolates with different pathotypes shared the same haplotype and others with different haplotypes harboured identical pathotype. There was a weak correlation between virulent pathotypes and molecular haplotypes. [source]


    Transcription activator-like type III effector AvrXa27 depends on OsTFIIA,5 for the activation of Xa27 transcription in rice that triggers disease resistance to Xanthomonas oryzae pv. oryzae

    MOLECULAR PLANT PATHOLOGY, Issue 6 2009
    KEYU GU
    SUMMARY The transcription activator-like (TAL) type III effector AvrXa27 from Xanthomonas oryzae pv. oryzae (Xoo) strain PXO99A activates the transcription of the host resistance gene Xa27, which results in disease resistance to bacterial blight (BB) in rice. In this study, we show that AvrXa27-activated Xa27 transcription requires host general transcription factor OsTFIIA,5. The V39E substitution in OsTFIIA,5, encoded by the recessive resistance gene xa5 in rice, greatly attenuates this activation in xa5 and Xa27 double homozygotes on inoculation with Xa27 -incompatible strains. The xa5 gene also causes attenuation in the induction of Xa27 by AvrXa27 expressed in rice. The xa5 -mediated attenuation of Xa27 -mediated resistance to PXO99A is recessive. Intriguingly, xa5 -mediated resistance to xa5 -incompatible strains is also down-regulated in the xa5 and Xa27 double homozygotes. In addition, AvrXa27 expressed in planta shows weak virulence activity in the xa5 genetic background and causes enhanced susceptibility of the plants to BB inoculation. The results suggest that TAL effectors target host general transcription factors to directly manipulate the host transcriptional machinery for virulence and/or avirulence. The identification of xa5 -mediated attenuation of Xa27 -mediated resistance to Xoo provides a guideline for breeding resistance to BB when pyramiding xa5 with other resistance genes. [source]


    Characterization of four rice mutants with alterations in the defence response pathway

    MOLECULAR PLANT PATHOLOGY, Issue 1 2005
    M. A. CAMPBELL
    SUMMARY A fast-neutron mutagenized population of rice seedlings was screened with Magnaporthe grisea, the causal agent of rice blast disease, to identify mutants with alterations in the defence response. Three mutant lines, ebr1, ebr2 and ebr3 (enhanced blast resistance) were identified that display enhanced resistance to M. grisea. ebr1 and ebr3 also confer enhanced resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). ebr3 develops a lesion mimic (LM) phenotype upon inoculation with M. grisea, and the phenotype is also induced by a shift in environmental conditions. The fourth mutant line, ncr1 (necrosis in rice), has an LM phenotype under all conditions tested and lacks enhanced resistance to either M. grisea or Xoo. Complementation testing using the mutant lines ebr3 and ncr1 indicates that the ebr3 and ncr1 loci are nonallelic and recessive. ebr1 and ebr2 display no alterations in expression of the rice pathogenesis-related (PR) genes PBZ1 and PR1, compared to wild-type CO39. ebr3 has an elevated expression of PBZ1 and PR1 only in tissue displaying the LM phenotype. ncr1 strongly expresses PBZ1 in tissue displaying the LM phenotype, whereas PR1 expression in this tissue is similar to wild-type CO39. [source]


    Promoter elements of rice susceptibility genes are bound and activated by specific TAL effectors from the bacterial blight pathogen, Xanthomonas oryzae pv. oryzae

    NEW PHYTOLOGIST, Issue 4 2010
    Patrick R÷mer
    Summary ,Plant pathogenic bacteria of the genus Xanthomonas inject transcription activator-like effector (TALe) proteins that bind to and activate host promoters, thereby promoting disease or inducing plant defense. TALes bind to corresponding UPT (up-regulated by TALe) promoter boxes via tandemly arranged 34/35-amino acid repeats. Recent studies uncovered the TALe code in which two amino acid residues of each repeat define specific pairing to UPT boxes. ,Here we employed the TALe code to predict potential UPT boxes in TALe-induced host promoters and analyzed these via ,-glucuronidase (GUS) reporter and electrophoretic mobility shift assays (EMSA). ,We demonstrate that the Xa13, OsTFX1 and Os11N3 promoters from rice are induced directly by the Xanthomonas oryzae pv. oryzae TALes PthXo1, PthXo6 and AvrXa7, respectively. We identified and functionally validated a UPT box in the corresponding rice target promoter for each TALe and show that box mutations suppress TALe-mediated promoter activation. Finally, EMSA demonstrate that code-predicted UPT boxes interact specifically with corresponding TALes. ,Our findings show that variations in the UPT boxes of different rice accessions correlate with susceptibility or resistance of these accessions to the bacterial blight pathogen. [source]


    Functional analysis of rice NPR1 -like genes reveals that OsNPR1/NH1 is the rice orthologue conferring disease resistance with enhanced herbivore susceptibility,

    PLANT BIOTECHNOLOGY JOURNAL, Issue 2 2007
    Yuexing Yuan
    Summary The key regulator of salicylic acid (SA)-mediated resistance, NPR1, is functionally conserved in diverse plant species, including rice (Oryza sativa L.). Investigation in depth is needed to provide an understanding of NPR1 -mediated resistance and a practical strategy for the improvement of disease resistance in the model crop rice. The rice genome contains five NPR1 -like genes. In our study, three rice homologous genes, OsNPR1/NH1, OsNPR2/NH2 and OsNPR3, were found to be induced by rice bacterial blight Xanthomonas oryzae pv. oryzae and rice blast Magnaporthe grisea, and the defence molecules benzothiadiazole, methyl jasmonate and ethylene. We confirmed that OsNPR1 is the rice orthologue by complementing the Arabidopsis npr1 mutant. Over-expression of OsNPR1 conferred disease resistance to bacterial blight, but also enhanced herbivore susceptibility in transgenic plants. The OsNPR1-green fluorescent protein (GFP) fusion protein was localized in the cytoplasm and moved into the nucleus after redox change. Mutations in its conserved cysteine residues led to the constitutive localization of OsNPR1(2CA)-GFP in the nucleus and also abolished herbivore hypersensitivity in transgenic rice. Different subcellular localizations of OsNPR1 antagonistically regulated SA- and jasmonic acid (JA)-responsive genes, but not SA and JA levels, indicating that OsNPR1 might mediate antagonistic cross-talk between the SA- and JA-dependent pathways in rice. This study demonstrates that rice has evolved an SA-mediated systemic acquired resistance similar to that in Arabidopsis, and also provides a practical approach for the improvement of disease resistance without the penalty of decreased herbivore resistance in rice. [source]


    Pyramiding of Xa7 and Xa21 for the improvement of disease resistance to bacterial blight in hybrid rice

    PLANT BREEDING, Issue 6 2006
    J. Zhang
    Abstract ,Minghui 63' is a restorer line widely used in hybrid rice production in China for the last two decades. This line and its derived hybrids, including ,Shanyou 63', are susceptible to bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo). To improve the bacterial blight resistance of hybrid rice, two resistance genes Xa21 and Xa7, have been introgressed into ,Minghui 63' by marker-assisted selection and conventional backcrossing, respectively. The single resistance gene-introgressed lines, Minghui 63 (Xa21) and Minghui 63 (Xa7) had higher levels of resistance to bacterial blight than their derived hybrids, Shanyou 63 (Xa21) or Shanyou 63 (Xa7). Both Xa21 and Xa7 showed incomplete dominance in the heterozygous background of rice hybrids by infection with GX325 and KS-1-21. The improved restorer lines, with the homozygous genotypes, Xa21Xa21 or Xa7Xa7, were more resistant than their hybrids with the heterozygous genotypes Xa21xa21 or Xa7xa7. To further enhance the bacterial blight resistance of ,Minghui 63' and its hybrids, Xa21 and Xa7 were pyramided into the same background using molecular marker-aided selection. The restorer lines developed with the resistance genes Xa21 and Xa7, and their derived hybrids were evaluated for resistance after inoculation with 10 isolates of pathogens from China, Japan and the Philippines, and showed a higher level of resistance to BB than the restorer lines and derived hybrids having only one of the resistance genes. The pyramided double resistance lines and their derived hybrids have the same high level of resistance to BB. These results clearly indicate that pyramiding of dominant genes is a useful approach for improving BB resistance in hybrid rice. [source]


    Proteomic analysis of rice plasma membrane reveals proteins involved in early defense response to bacterial blight

    PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 9 2007
    Fang Chen
    Abstract Plant plasma membrane (PM) proteins play important roles in signal transduction during defense response to an attacking pathogen. By using an improved method of PM protein preparation and PM-bound green fluorescent protein fusion protein as a visible marker, we conducted PM proteomic analysis of the rice suspension cells expressing the disease resistance gene Xa21, to identify PM components involved in the early defense response to bacterial blight (Xanthomonas oryzae pv. oryzae). A total of 20 regulated protein spots were observed on 2-D gels of PM fractions at 12 and 24,h after pathogen inoculation, of which some were differentially regulated between the incompatible and compatible interactions mediated by Xa21, with good correlation between biological repeats. Eleven protein spots with predicted functions in plant defense were identified by MS/MS, including nine putative PM-associated proteins H+ -ATPase, protein phosphatase, hypersensitive-induced response protein (OsHIR1), prohibitin (OsPHB2), zinc finger and C2 domain protein, universal stress protein (USP), and heat shock protein. OsHIR1 was modified by the microbal challenge, leading to two differentially accumulated protein spots. Transcript analysis showed that most of the genes were also regulated at transcriptional levels. Our study would provide a starting point for functionality of PM proteins in the rice defense. [source]


    Crystallization and preliminary X-ray crystallographic analysis of DNA gyrase GyrB subunit from Xanthomonas oryzae pv. oryzae

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2010
    Ha Yun Jung
    DNA gyrase is a type II topoisomerase that is essential for chromosome segregation and cell division owing to its ability to modify the topological forms of bacterial DNA. In this study, the N-terminal fragment of the GyrB subunit of DNA gyrase from Xanthomonas oryzae pv. oryzae was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.10,┼ resolution using a synchrotron-radiation source. The crystal belonged to space group I41, with unit-cell parameters a = b = 110.27, c = 70.75,┼. The asymmetric unit contained one molecule, with a VM of 2.57,┼3,Da,1 and a solvent content of 50.2%. [source]


    Cloning, expression, crystallization and preliminary X-ray crystallographic analysis of leucine aminopeptidase (LAP) from the pepA gene of Xanthomonas oryzae pv. oryzae

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2009
    Kim-Hung Huynh
    Xanthomonas oryzae pv. oryzae (Xoo) causes the serious disease bacterial blight in rice. The pepA (Xoo0834) gene from Xoo is one of around 100 genes that have been selected for the design of antibacterial drugs. The pepA gene encodes leucine aminopeptidase (LAP), an exopeptidase that catalyzes the hydrolysis of leucine residues from the N-terminus of a protein or peptide. This enzyme was expressed in Escherichia coli, purified and crystallized, and preliminary X-ray structural studies have been carried out. The LAP crystal diffracted to 2.6,┼ resolution and belonged to the cubic space group P213. The unit-cell volume of the crystal was compatible with the presence of two monomers in the asymmetric unit. [source]


    Crystallization and X-ray diffraction data collection of topoisomerase IV ParE subunit from Xanthomonas oryzae pv. oryzae

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 6 2009
    Hye Jeong Shin
    Topoisomerase IV is involved in topological changes in the bacterial genome using the free energy from ATP hydrolysis. Its functions are the decatenation of daughter chromosomes following replication by DNA relaxation and double-strand DNA breakage. In this study, the N-terminal fragment of the topoisomerase IV ParE subunit from Xanthomonas oryzae pv. oryzae was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.15,┼ resolution using a synchrotron-radiation source. The crystal belonged to space group P42212, with unit-cell parameters a = b = 105.30, c = 133.76,┼. The asymmetric unit contains one molecule, with a corresponding VM of 4.21,┼3,Da,1 and a solvent content of 69.6%. [source]


    Cloning, expression, crystallization and preliminary X-ray crystallographic analysis of ,-ketoacyl-ACP synthase III (FabH) from Xanthomonas oryzae pv. oryzae

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2009
    Kim-Hung Huynh
    The bacterial ,-ketoacyl-ACP synthase III (KASIII) encoded by the gene fabH (Xoo4209) from Xanthomonas oryzae pv. oryzae, a plant pathogen, is an important enzyme in the elongation steps of fatty-acid biosynthesis. It is expected to be one of the enzymes responsible for bacterial blight (BB), a serious disease that results in huge production losses of rice. As it represents an important target for the development of new antibacterial drugs against BB, determination of the crystal structure of the KAS III enzyme is essential in order to understand its reaction mechanism. In order to analyze the structure and function of KAS III, the fabH (Xoo4209) gene was cloned and the enzyme was expressed and purified. The KASIII crystal diffracted to 2.05,┼ resolution and belonged to the orthorhombic space group P21212, with unit-cell parameters a = 69.8, b = 79.5, c = 62.3,┼. The unit-cell volume of the crystal is compatible with the presence of a single monomer in the asymmetric unit, with a corresponding Matthews coefficient VM of 2.27,┼3,Da,1 and a solvent content of 45.8%. [source]


    Cloning, expression, crystallization and preliminary X-ray crystallographic analysis of glutamyl-tRNA synthetase (Xoo1504) from Xanthomonas oryzae pv. oryzae

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2009
    Thanh Thi Ngoc Doan
    The gltX gene from Xanthomonas oryzae pv. oryzae (Xoo1504) encodes glutamyl-tRNA synthetase (GluRS), one of the most important enzymes involved in bacterial blight (BB), which causes huge production losses of rice worldwide. GluRS is a class I-type aminoacyl-tRNA synthetase (aaRS) that is primarily responsible for the glutamylation of tRNAGlu. It plays an essential role in protein synthesis, as well as the regulation of cells, in all organisms. As it represents an important target for the development of new antibacterial drugs against BB, determination of the three-dimensional structure of GluRS is essential in order to understand its catalytic mechanism. In order to analyze its structure and function, the gltX gene was cloned and the GluRS enzyme was expressed, purified and then crystallized. A GluRS crystal belonging to the monoclinic space group C2 diffracted to 2.8,┼ resolution and had unit-cell parameters a = 186.8, b = 108.4, c = 166.1,┼, , = 96.3░. The unit-cell volume of the crystal allowed the presence of six to eight monomers in the asymmetric unit, with a corresponding Matthews coefficient (VM) range of 2.70,2.02,┼3,Da,1 and a solvent-content range of 54.5,39.3%. [source]