| identification of a family of avirulence genes from xanthomonas oryzae pv. oryzae. | races of xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight of rice, interact with cultivars of rice in a gene-for-gene specific manner. multiple dna fragments of various sizes from all strains of x. o. pv. oryzae hybridized with avrbs3, an avirulence gene from xanthomonas campestris pv. vesicatoria, in southern blots; this suggests the presence of several homologs and possibly a gene family. a genomic library of a race 2 strain of x. o. pv. oryzae, which is avirulent on rice cu ... | 1992 | 1335800 |
| assessment of genetic diversity and population structure of xanthomonas oryzae pv. oryzae with a repetitive dna element. | a repetitive dna element cloned from xanthomonas oryzae pv. oryzae was used to assess the population structure and genetic diversity of 98 strains of x. oryzae pv. oryzae collected between 1972 and 1988 from the philippine islands. genomic dna from x. oryzae pv. oryzae was digested with ecori and analyzed for restriction fragment length polymorphisms (rflps) with repetitive dna element as a probe. twenty-seven rflp types were identified; there was no overlap of rflp types among the six races fro ... | 1992 | 1353345 |
| genetic and physical analysis of the rice bacterial blight disease resistance locus, xa21. | nearly isogenic lines (nils) of rice (oryza sativa) differing at a locus conferring resistance to the pathogen xanthomonas oryzae pv. oryzae were surveyed with 123 dna markers and 985 random primers using restriction fragment length plymorphism (rflp) and random amplified polymorphic dna (rapd) analysis. one chromosome 11 marker (rg103) detected polymorphism between the nils that cosegregated with xa21. all other chromosome 11 dna markers tested were monomorphic between the nils, localizing the ... | 1992 | 1362973 |
| a homolog of an escherichia coli phosphate-binding protein gene from xanthomonas oryzae pv. oryzae. | a xanthomonas oryzae pv. oryzae gene with sequence similarity to an escherichia coli phosphate-binding protein gene (phos) produces a periplasmic protein of apparent m(r) 35,000 when expressed in e. coli. amino terminal sequencing revealed that a signal peptide is removed during transport to the periplasm in e. coli. | 1995 | 7579584 |
| rice cationic peroxidase accumulates in xylem vessels during incompatible interactions with xanthomonas oryzae pv oryzae. | a cationic peroxidase, po-c1 (molecular mass 42 kd, isoelectric point 8.6), which is induced in incompatible interactions between the vascular pathogen xanthomonas oryzae pv oryzae and rice (oryza sativa l.), was purified. amino acid sequences from chemically cleaved fragments of po-c1 exhibited a high percentage of identity with deduced sequences of peroxidases from rice, barley, and wheat. polyclonal antibodies were raised to an 11-amino acid oligopeptide (poc1a) that was derived from a domain ... | 1995 | 7770527 |
| avrxa10 protein is in the cytoplasm of xanthomonas oryzae pv. oryzae. | avrxa10 from xanthomonas oryzae pv. oryzae was tagged with a unique hydrophilic octapeptide (flag) to permit antibody-mediated identification and purification of the gene product. x. o. pv. oryzae that produced tagged avrxa10 elicited a hypersensitive response (hr) on rice cultivars containing the resistance gene xa-10, but not on cultivars lacking xa-10. the tagged avrxa10 protein purified from escherichia coli or x. o. pv. oryzae did not elicit a hypersensitive response in rice with the xa-10 ... | 1994 | 7873783 |
| characterization of two novel filamentous phages of xanthomonas. | two filamentous phages of xanthomonas campestris pv. vesicatoria and xanthomonas oryzae pv. oryzae were isolated and designated phi xv and phi xo, respectively. they were similar to other filamentous phages of xanthomonas in (i) shape, (ii) restrictive host specificity, (iii) high stability, (iv) an ssdna genome, (v) a dsdna as the replicative form (rf), (vi) propagation without lysis of host cells and (vii) ability to integrate into the host chromosome. these phages showed sequence homology to ... | 1994 | 8077961 |
| identification of the xorii methyltransferase gene and a vsr homolog from xanthomonas oryzae pv. oryzae. | the gene encoding the xorii methyltransferase (m.xorii) was cloned from xanthomonas oryzae pv. oryzae and characterized in escherichia coli. the m.xorii activity was localized to a 3.1 kb bamhi-bstxi fragment, which contained two open reading frames (orfs) of 1272 nucleotides (424 amino acids) and 408 nucleotides (136 amino acids). ten polypeptide domains conserved in other m5 cytosine methyltransferases (mtases) were identified in the deduced amino acid sequence of the 1272 orf. e. coli mrr+ st ... | 1994 | 8078464 |
| isolation and expression in escherichia coli of a xanthomonas oryzae reca-like gene. | the reca gene from the bacterium xanthomonas oryzae pv. oryzae (xoo), a rice pathogen, was cloned based on its ability to complement dna repair defects of escherichia coli reca- mutants. the xoo reca was localized to a 1.3-kb sau3ai-xhoi fragment and, when cloned into pbr322, specifies increased methylmethanesulfonate and mitomycin c resistance to e. coli reca mutants and allows lambda red- gam- to plaque on an e. coli reca- host. an e. coli reca- strain harboring a plasmid containing the xoo re ... | 1993 | 8406033 |
| restoration of pathogenicity of avirulent xanthomonas oryzae pv. oryzae and x. campestris pathovars by reciprocal complementation with the hrpxo and hrpxc genes and identification of hrpx function by sequence analyses. | the molecular basis of pathogenesis by xanthomonas oryzae pv. oryzae has been partly elucidated by the identification of a gene, hrpxo, required for bacterial blight on rice. a mutation in hrpxo results in the loss of pathogenicity on rice and the loss of hypersensitivity on nonhosts such as datura stramonium and radishes. pathogenicity and its ability to cause the hypersensitive reaction is restored by complementing the mutant with the heterologous hrpxc gene derived from x. campestris pv. camp ... | 1993 | 8458844 |
| a receptor kinase-like protein encoded by the rice disease resistance gene, xa21. | the rice xa21 gene, which confers resistance to xanthomonas oryzae pv. oryzae race 6, was isolated by positional cloning. fifty transgenic rice plants carrying the cloned xa21 gene display high levels of resistance to the pathogen. the sequence of the predicted protein, which carries both a leucine-rich repeat motif and a serine-threonine kinase-like domain, suggests a role in cell surface recognition of a pathogen ligand and subsequent activation of an intracellular defense response. characteri ... | 1995 | 8525370 |
| rapid inhibition of protein histidine phosphorylation by uv-irradiation in xanthomonas oryzae pv. oryzae. | exposure of xanthomonas oryzae pv. oryzae cells to 254 nm uv radiation resulted in an alteration of protein phosphorylation. labelling of the phosphohistidine-containing proteins with molecular masses of 81 and 32 kda, named p81 and p32, was rapidly reduced following uv irradiation in the early exponential cells, but the decrease was not detected in mid-exponential cells. mitomycin c, a dna replication inhibitor, and rifampicin, a drug generally used to inhibit rna synthesis and dna replication, ... | 1995 | 8586267 |
| heterologous growth phase- and temperature-dependent expression and h2o2 toxicity protection of a superoxide-inducible monofunctional catalase gene from xanthomonas oryzae pv. oryzae. | catalase is an important protective enzyme against h2o2 toxicity. here, we report the characterization of a xanthomonas oryzae pv. oryzae catalase gene (katx). the gene was localized and its nucleotide sequence was determined. the gene codes for a 77-kda polypeptide. the deduced katx amino acid sequence shares regions of high identity with other monofunctional catalases in a range of organisms from bacteria to eukaryotes. the transcriptional regulation of katx was atypical of bacterial monofunct ... | 1996 | 8655557 |
| [a pcr marker-based selection for resistance to bacterial blight in rice]. | molecular marker-based selection in plant breeding requires not only suitable molecular markers closely linked to the known genes, but a simple, economic and reliable analyzing technique. we report here a useful pcr marker for genetic diagnostics in breeding for resistance to rice bacterial blight. xa21 is a newly found gene of rice which confers resistance to bacterial blight caused by xanthomonas oryzae pv. oryzae. we produced two f2 populations between one resistant line irbb21 containing xa2 ... | 1996 | 8695180 |
| cloning and characterization of the rpfc gene of xanthomonas oryzae pv. oryzae: involvement in exopolysaccharide production and virulence to rice. | rpfc is one of a cluster of genes which coordinately regulate the synthesis of extracellular enzymes and exopolysaccharide and pathogenicity in xanthomonas campestris pv. campestris, the black rot pathogen of brassicas. an rpfc homolog which could functionally complement an rpfc mutant of x. campestris pv. campestris was identified in xanthomonas oryzae pv. oryzae and the gene was characterized. mutation of this gene in x. oryzae pv. oryzae had no effect on extracellular enzymes, but exopolysacc ... | 1996 | 8810082 |
| rifampicin: an inhibitor of xp12-specific protein phosphorylation in xanthomonas oryzae pv. oryzae. | phosphorylation of the three xp12-specific phosphoproteins was drastically reduced by rifampicin, an antibiotic that specifically inhibits the host-cell rna polymerase. however, this inhibitory effect could not be found in spontaneous mutants of xanthomonas oryzae pv. oryzae whose rna polymerase are resistant to the drug. the inhibitory effect of rifampicin treatment also resulted suppression of the xp12 multiplication cycle. this implies the physiological significance of this effect and support ... | 1996 | 8837466 |
| the cloned gene, xa21, confers resistance to multiple xanthomonas oryzae pv. oryzae isolates in transgenic plants. | the cloned rice gene, xa21, confers resistance to multiple pathogen isolates of xanthomonas oryzae pv. oryzae in transgenic plants. the resistance phenotype was stably transmitted to t1 progeny and inherited as a single locus. the t1 progeny were tested for resistance to 32 x. oryzae pv. oryzae isolates from eight countries. both the engineered line and the donor line showed resistance to 29 isolates and susceptibility to three isolates. the identical resistance spectrum of both lines indicates ... | 1996 | 8969533 |
| the molecular basis of disease resistance in rice. | the rice gene xa21 conferring resistance to xanthomonas oryzae pv. oryzae (xoo), was isolated using a map-based cloning strategy. compared with previously cloned genes, the structure of xa21 represents a novel class of plant disease r genes encoding a putative receptor kinase (rk). this article proposes a model for the mode of action of xa21 and summarizes our current knowledge of the modular basis of resistance in rice to bacterial leaf blight and blast. | 1997 | 9291971 |
| differential induction of a peroxidase gene family during infection of rice by xanthomonas oryzae pv. oryzae. | induction of peroxidase has been correlated with resistant interactions between rice and xanthomonas oryzae pv. oryzae. to assist in analysis of the role of rice peroxidases in plant defense against the bacterial pathogen, three peroxidase genes, pox22.3, pox8.1, and pox5.1, were identified from a rice cdna library that was constructed from leaves of plants undergoing a resistant reaction. these genes were highly similar in nucleic acid and amino acid sequences and belonged to a gene family. the ... | 1997 | 9304860 |
| the bacterial pigment xanthomonadin offers protection against photodamage. | xanthomonas oryzae pv. oryzae is a bacterial pathogen that causes leaf blight, a serious disease of rice. most members of the genus xanthomonas produce yellow, membrane bound, brominated aryl polyene pigments called xanthomonadins whose functional role is unclear. we find that pigment-deficient mutants of x. oryzae pv. oryzae exhibit hypersensitivity to photobiological damage. a clone containing the xanthomonadin biosynthetic gene cluster alleviates the hypersensitivity of the pigment-deficient ... | 1997 | 9350981 |
| expression of xa1, a bacterial blight-resistance gene in rice, is induced by bacterial inoculation. | the xa1 gene in rice confers resistance to japanese race 1 of xanthomonas oryzae pv. oryzae, the causal pathogen of bacterial blight (bb). we isolated the xa1 gene by a map-based cloning strategy. the deduced amino acid sequence of the xa1 gene product contains nucleotide binding sites (nbs) and a new type of leucine-rich repeats (lrr); thus, xa1 is a member of the nbs-lrr class of plant disease-resistance genes, but quite different from xa21, another bb-resistance gene isolated from rice. inter ... | 1998 | 9465073 |
| characterization and expression analysis of a xanthomonas oryzae pv. oryzae reca. | nucleotide sequence of xanthomonas oryzae pv. oryzae (xoo) dna from psm-a1 was determined and sequence analysis revealed an orf with high homology to reca proteins. expression analysis using an anti-reca antibody demonstrates that mms treatment induces reca in xanthomonas strains but not in an escherichia coli harbouring cloned xoo reca. this indicates the existence of a reca regulatory mechanism in xanthomonas that is not function in e. coli. in xoo, reca was highly induced by treatments with c ... | 1998 | 9465392 |
| distribution of xanthomonas oryzae pv. oryzae dna modification systems in asia. | the presence or absence of two dna modification systems, xori and xorii, in 195 strains of xanthomonas oryzae pv. oryzae collected from different major rice-growing countries of asia was assessed. all four possible phenotypes (xori+ xorii+, xori+ xorii-, xori- xorii+ and xori- xorii-) were detected in the population at a ratio of approximately 1:2:2:2. the xori+ xorii+ and xori- xorii+ phenotypes were observed predominantly in strains from southeast asia (philippines, malaysia, and indonesia), w ... | 1998 | 9572933 |
| xa21d encodes a receptor-like molecule with a leucine-rich repeat domain that determines race-specific recognition and is subject to adaptive evolution. | the rice xa21 gene confers resistance to xanthomonas oryzae pv oryzae in a race-specific manner. analysis of the inheritance patterns and resistance spectra of transgenic plants carrying six xa21 gene family members indicated that one member, designated xa21d, displayed a resistance spectrum identical to that observed for xa21 but conferred only partial resistance. xa21d encodes a receptor-like protein carrying leucine-rich repeat (lrr) motifs in the presumed extracellular domain. the xa21d tran ... | 1998 | 9596635 |
| avrxa10 contains an acidic transcriptional activation domain in the functionally conserved c terminus. | the avrxa10 gene of xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight of rice, is a member of the avrbs3 avirulence gene family and directs the elicitation of resistance in a gene-for-gene manner on rice lines carrying the resistance gene xa10. the carboxyl (c) terminus of avrxa10 has a previously undescribed domain that is structurally similar to the acidic activation domain of many eukaryotic transcription factors in addition to three nuclear localization signal (nls) sequenc ... | 1998 | 9675896 |
| construction and physiological analysis of a xanthomonas oryzae pv. oryzae reca mutant. | a xoo reca insertion inactivation mutant was constructed. the mutant, lacking reca, showed increased sensitivity towards mutagen killing. this phenotype could be complemented by a cloned, functional reca. unlike other bacteria, both the reca mutant and the parental strain had similar level of resistance to h2o2 killing and peroxide-induced mutagenesis. | 1998 | 9868770 |
| a "defeated" rice resistance gene acts as a qtl against a virulent strain of xanthomonas oryzae pv. oryzae. | the genetic components responsible for qualitative and quantitative resistance of rice plants to three strains (cr4, cxo8, and cr6) of xanthomonas oryzae pv. oryzae (xoo) were investigated using a set of 315 recombinant inbred lines (rils) from the cross lemont (japonica) x teqing (indica) and a complete linkage map with 182 well distributed rflp markers. we mapped a major gene (xa4) and ten quantitative trait loci (qtls) which were largely responsible for segregation of the resistance phenotype ... | 1999 | 10071210 |
| a transposon insertion in the gumg homologue of xanthomonas oryzae pv. oryzae causes loss of extracellular polysaccharide production and virulence. | xanthomonas oryzae pv. oryzae causes a serious disease of rice called bacterial leaf blight. it produces copious amounts of extracellular polysaccharide (eps). an eps- and virulence-deficient mutant of x. oryzae pv. oryzae was isolated by tn5 mutagenesis. the mutant allele in this strain was cloned by transposon tagging in the escherichia coli vector pbluescript and the dna sequences flanking the transposon insertion site were determined. computer-based similarity searches in the dna database us ... | 1999 | 10481086 |
| the c terminus of avrxa10 can be replaced by the transcriptional activation domain of vp16 from the herpes simplex virus. | the avirulence gene avrxa10 of xanthomonas oryzae pv oryzae directs the elicitation of resistance in a gene-for-gene manner in rice lines carrying the resistance gene xa10. we have localized a transcriptional activator domain in the c terminus of avrxa10 by using amino acid replacement mutagenesis. one mutant, with replacements at three hydrophobic amino acid residues in the c-terminal domain, was defective for transcriptional activation in yeast and avirulence activity in rice. the activation d ... | 1999 | 10488234 |
| short communication: developmental control of xa21-mediated disease resistance in rice. | the rice resistance gene xa21 confers resistance against the bacterial pathogen xanthomonas oryzae pv. oryzae (xoo). the molecular genetic mechanism controlling the integration of the xa21-mediated disease resistance response with the developmental program in rice is under study in this model system. reproducible means of infecting plants at certain developmental stages were designed based on the timing of full expansion of the leaf. xa21-resistance progressively increases from the susceptible j ... | 1999 | 10571882 |
| identification of two novel hrp-associated genes in the hrp gene cluster of xanthomonas oryzae pv. oryzae. | we have cloned a hrp gene cluster from xanthomonas oryzae pv. oryzae. bacteria with mutations in the hrp region have reduced growth in rice leaves and lose the ability to elicit a hypersensitive response (hr) on the appropriate resistant cultivars of rice and the nonhost plant tomato. a 12,165-bp portion of nucleotide sequence from the presumed left end and extending through the hrpb operon was determined. the region was most similar to hrp genes from xanthomonas campestris pv. vesicatoria and r ... | 2000 | 10714988 |
| mutants of xanthomonas oryzae pv. oryzae deficient in general secretory pathway are virulence deficient and unable to secrete xylanase. | xanthomonas oryzae pv. oryzae (xoo) causes bacterial leaf blight, a serious disease of rice. a virulence- and xylanase-deficient mutant of xoo was isolated following ethyl methane sulfonate (ems) mutagenesis. a cosmid clone that restored virulence and xylanase secretion was obtained from a genomic library by functional complementation. transposon mutagenesis and marker exchange studies revealed genes on the cloned dna that were required for xylanase production and virulence. sequence analysis wi ... | 2000 | 10755302 |
| the virulence factor avrxa7 of xanthomonas oryzae pv. oryzae is a type iii secretion pathway-dependent nuclear-localized double-stranded dna-binding protein. | avrxa7 is a member of the avrbs3 avirulence gene family, which encodes proteins targeted to plant cells by a type iii secretion apparatus. avrxa7, the product of avrxa7, is also a virulence factor in strain pxo86 of xanthomonas oryzae pv. oryzae. avirulence and virulence specificities are associated with the central repeat domain, which, in avrxa7, consists of 25.5 direct repeat units. mutations in three c-terminal nuclear localization signal motifs eliminated avirulence and virulence activities ... | 2000 | 10931960 |
| stationary-phase variation due to transposition of novel insertion elements in xanthomonas oryzae pv. oryzae. | xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. spontaneous mutants which are deficient for virulence and extracellular polysaccharide (eps) production accumulate in large numbers in stationary-phase cultures of this bacterium, a phenomenon which we have called stationary-phase variation. a clone (psd1) carrying the eps biosynthetic gene (gum) cluster of x. oryzae pv. oryzae restored eps production and virulence to several spv (for stationary-phase variatio ... | 2000 | 10940020 |
| [introduction of wide spectrum rice bacterial blight resistance gene xa21 into two-line genic male sterile rice variety pei'ai 64s]. | agrobacterium-mediated transformation of two-line genic male sterile indica rice variety pei'ai 64s was conducted using a cloned gene, xa21, as the foreign gene and mature embryo calli as the recipients. a total of 46 transgenic plants had been obtained. the pcr analysis and southern blotting showed the integration of xa21 gene into the genome the transgenic plants. results of inoculation with philippine race 6 of xanthomonas oryzae pv. oryzae indicated that most of transgenic plants obtained hi ... | 2000 | 10976312 |
| isolation and characterization of disease resistance gene homologues from rice cultivar ir64. | we initiated a search for disease resistance (r) gene homologues in rice cultivar ir64, one of the most agronomically important rice varieties in the world, with the assumption that some of these homologues would correspond to previously identified disease resistance loci. a family of rice r gene homologues was identified using the arabidopsis nbs-lrr disease resistance gene rps2 as a hybridization probe. because member genes of this rice r gene family exhibit features characteristic of the nbs- ... | 2000 | 11024284 |
| transgenic expression of cecropin b, an antibacterial peptide from bombyx mori, confers enhanced resistance to bacterial leaf blight in rice. | the short persistence of cecropin b peptide in plants, due to post-translational degradation, is a serious impediment in its effective utilization for developing bacterial resistance transgenic plants. two dna constructs encoding the full-length precursor of cecropin b peptide and the mature sequence of cecropin b peptide preceded by a signal peptide derived from rice chitinase gene were transformed in rice. the differences in the transcriptional levels in independent transgenic lines showed mod ... | 2000 | 11056212 |
| predicting durability of a disease resistance gene based on an assessment of the fitness loss and epidemiological consequences of avirulence gene mutation. | durability of plant disease resistance (r) genes may be predicted if the cost of pathogen adaptation to overcome resistance is understood. adaptation of the bacterial blight pathogen, xanthomonas oryzae pv. oryzae (xoo), to virulence in rice is the result of the loss of pathogen avirulence gene function, but little is known about its effect on aggressiveness under field conditions. we evaluated the cost in pathogenic fitness (aggressiveness and persistence) associated with adaptation of xoo to v ... | 2000 | 11095723 |
| xanthomonas oryzae pv. oryzae avirulence genes contribute differently and specifically to pathogen aggressiveness. | genomic copies of three xanthomonas oryzae pv. oryzae avirulence (avr) genes, avrxa7, avrxal0, and avrxa5, and four homologous genes, ab3.5, ab3.6, ab4.3, and ab4.5, were mutagenized individually or in combination to study the roles of avr genes in one component of pathogen fitness, i.e., aggressiveness or the amount of disease x. oryzae pv. oryzae causes in susceptible rice lines. these x. oryzae pv. oryzae genes are members of the highly related xanthomonas avrbs3 gene family. compared to the ... | 2000 | 11106024 |
| pigment and virulence deficiencies associated with mutations in the aroe gene of xanthomonas oryzae pv. oryzae. | xanthomonadins are yellow, membrane-bound pigments produced by members of the genus xanthomonas. we identified an ethyl methanesulfonate-induced xanthomonas oryzae pv. oryzae mutant (bxo65) that is deficient for xanthomonadin production and virulence on rice, as well as auxotrophic for aromatic amino acids (pig(-) vir(-) aro(-)). reversion analysis indicated that these multiple phenotypes are due to a single mutation. a genomic library of the wild-type strain was used to isolate a 7.0-kb clone t ... | 2001 | 11133452 |
| isolation of a xanthomonas oryzae pv. oryzae flagellar operon region and molecular characterization of flhf. | an 8.1-kb dna fragment from xanthomonas oryzae pv. oryzae that contains six open reading frames (orf) was cloned. the orf encodes proteins similar to flagellar proteins flhb, flha, flhf, and flia, plus two proteins of unknown function, orf234 and orf319, from bacillus subtilis and other organisms. these orf have a similar genomic organization to those of their homologs in other bacteria. theflhf gene product, flhf, has a gtp-binding motif conserved in its homologs. unlike its homologs, however, ... | 2001 | 11204784 |
| molecular characterization of the cdna encoding an acidic isoform of pr-1 protein in rice. | rice cdna encoding an acidic type of pathogenesis-related protein-1 (pr-1a) was cloned and characterized. the deduced pr-1a protein consisted of 168 amino acid residues, including 24 hydrophobic signal sequences at the n-terminus. the predicted molecular mass of the pr-1a was 15,728 da with a theoretical pi of 4.5, an indication of an acidic protein. the pr-la showed high homology to an acidic pr-1 of zea mays (74%) and a previously identified basic type pr-1 of rice (64%). both rice pr-1 and pr ... | 2001 | 11266113 |
| xanthomonas oryzae pv. oryzae reca is transcribed and regulated from multiple promoters. | transcription regulation of xanthomonas oryzae pv. oryzae reca was characterized. primer extension experiments showed that reca is transcribed from three promoters designated p1, p2 and p3. the sequences of -10 and -35 regions of these promoters have moderate homology to the proposed consensus sequence for a xanthomonas promoter. putative sos boxes were identified in the vicinity of p1 and p2 promoters. deletion analysis and in vivo monitoring of promoter activity of these promoters revealed tha ... | 2001 | 11287143 |
| transgenic rice plants expressing the ferredoxin-like protein (ap1) from sweet pepper show enhanced resistance to xanthomonas oryzae pv. oryzae. | we used particle bombardment to cotransform mature seed-derived rice callus (oryza sativa l., ssp. japonica, cv. eyi 105) with plasmids containing the linked marker genes gusa and hpt, and the ap1 gene encoding an amphipathic protein previously shown to delay the hypersensitive response induced in non-host plants by the pathogen pseudomonas syringae pv. syringae (pss). thirty-two independent lines of transgenic rice plants were regenerated, and 27 of these lines carried all three transgenes as s ... | 2001 | 11297801 |
| chromosome landing at the bacterial blight resistance gene xa4 locus using a deep coverage rice bac library. | xa4 is a dominantly inherited rice gene that confers resistance to philippine race 1 of the bacterial blight pathogen xanthomonas oryzae pv. oryzae in rice. in order to isolate the gene by positional cloning, a bacterial artificial chromosome (bac) library was constructed from genomic dna isolated from an xa4-harboring accession, irbb56. the library contains 55,296 clones with an average insert size of 132 kb, providing 14 rice genome equivalents. three dna markers closely linked to xa4 were use ... | 2001 | 11370857 |
| dissection of defence response pathways in rice. | the cloning of major resistance genes has led to a better understanding of the molecular biology of the steps for induction of resistance, yet much remains to be discovered about the downstream genes that collectively confer resistance, i.e. the defence response (dr) genes. we are dissecting the pathways contributing to resistance in rice by identifying a collection of mutants with deletions or other structural rearrangements in dr genes. the collection of rice mutants has been screened for many ... | 2001 | 11387980 |
| construction and characterization of a xanthomonas oryzae pv. oryzae bacterial artificial chromosome library. | xanthomonas oryzae pv. oryzae is an important plant pathogen which causes bacterial blight of rice. to facilitate genome studies of this bacterium, we have constructed a bacterial artificial chromosome (bac) library of strain maff 311018. it consisted of 750 clones representing 16 genome equivalents, and had an insert size ranging from 20 to 220 kb with an average size of 107 kb. this library is the first to be constructed from a x. oryzae pv. oryzae strain. the usefulness of this library was de ... | 2001 | 11410350 |
| evidence for a disease-resistance pathway in rice similar to the npr1-mediated signaling pathway in arabidopsis. | the arabidopsis npr1/nim1 gene is a key regulator of systemic acquired resistance (sar). over-expression of npr1 leads to enhanced resistance in arabidopsis. to investigate the role of npr1 in monocots, we over-expressed the arabidopsis npr1 in rice and challenged the transgenic plants with xanthomonas oryzae pv. oryzae (xoo), the rice bacterial blight pathogen. the transgenic plants displayed enhanced resistance to xoo. rna blot hybridization indicates that enhanced resistance requires expressi ... | 2001 | 11489188 |
| some tryptophan pathways in the phytopathogen xanthomonas oryzae pv. oryzae. | xanthomonas oryzae pv. oryzae, the causal organism of bacterial blight of rice which produces leaf blight as well as kresek (wilt) symptoms in plants were tested for indole, auxin production in culture supplemented with l-tryptophan. on the basis of indoleacetic acid (iaa) production the isolates were grouped into iaa-positive and iaa-negative. out of 17 isolates, 11 were iaa-positive while 6 were iaa-negative. the isolates metabolized tryptophan through two different routes and the isolates var ... | 2000 | 11501419 |
| exopolysaccharides of xanthomonas pathovar strains that infect rice and wheat crops. | in order to understand the mode of action of the taxonomically related pathogens xanthomonas campestris pv. translucens, xanthomonas oryzae pv. oryzae, and xanthomonas oryzae pv. oryzicola, which attack wheat and rice crops, we examined the compositional differences of their exopolysaccharides (epss). maximum production of polysaccharide in shake cultures of these pathogens was observed between 24 and 72 h. x. campestris pv. translucens, the leaf streak pathogen of wheat, produced a higher amoun ... | 2001 | 11525629 |
| identification of a h+/glucose and galactose symporter gene glt from xanthomonas oryzae pv. oryzae. | we identified a glucose and galactose transporter gene from the plant-pathogenic bacterium xanthomonas oryzae pv. oryzae. sequence analysis indicated that the gene, named glt, encoded a polypeptide of 592 amino acid residues and the product was significantly homologous with members of the na+/glucose cotransporter (sglt) family from mammalian and bacterial origin, especially with vsglt from vibrio parahaemolyticus (50% identity). glt functioned as a glucose and galactose transporter in an escher ... | 2001 | 11529561 |
| detection of xanthomonas oryzae pv. oryzae in artificially inoculated and naturally infected rice seeds and plants by molecular techniques. | a polymerase chain reaction (pcr) technique was developed for detecting the presence of xanthomonas oryzae pv. oryzae, the bacterial leaf blight (blb) pathogen in rice seed and for studying the transmission of this bacterium from seed to plant. primers txt and txt4r from an insertion sequence (is1113) of the pathogen were used to amplify a 964-bp dna fragment. a combined biological and enzymatic amplification (bio-pcr) technique was used to detect the pathogen in naturally infected seed. the lev ... | 2001 | 11549016 |
| marker assisted selection of bacterial blight resistance genes in rice. | bacterial leaf blight caused by xanthomonas oryzae pv. oryzae is one of the most important diseases affecting rice production in asia. we were interested in surveying rice genotypes that are popularly used in the indian breeding program for conferring resistance to bacterial blight, using 11 stms and 6 sts markers. the basis of selection of these dna markers was their close linkage to xa5, xa13, and xa21 genes and their positions on the rice genetic map relative to bacterial blight resistance ge ... | 2001 | 11590832 |
| are the dominant and recessive plant disease resistance genes similar? a case study of rice r genes and xanthomonas oryzae pv. oryzae races. | the resistance of rice to its bacterial blight pathogen xanthomonas oryzae pv. oryzae (xoo) has both qualitative and quantitative components that were investigated using three near-isogenic line sets for four resistance (r) genes (xa4, xa5, xa13, and xa21) and 12 xoo races. our results indicate that these two resistance components of rice plants were associated with the properties of the r genes. the qualitative component of the r genes was reflected by their large effects against corresponding ... | 2001 | 11606550 |
| characterization of xanthomonas oryzae pv. oryzae recx, a gene that is required for high-level expression of reca. | analysis of the nucleotide sequence downstream from the xanthomonas oryzae pv. oryzae reca gene reveals two orfs designated orfx and recx. the former has the potential to code for a 5.6 kda protein of unknown function while the latter encodes for a putative 14.6 kda protein with homology to recx from various bacteria. northern blot analysis and rt-pcr results show that reca-orfx-recx are co-regulated and arranged in an operon. a recx mutant was constructed. the mutant has no obvious growth defec ... | 2001 | 11728720 |
| disassociation of sigma subunit from rna polymerase of xanthomonas oryzae pv. oryzae by phage xp10 infection. | the sigma subunit of xanthomonas oryzae pv. oryzae is disassociated from host rna polymerase after phage xp10 infection. to clarify the possible mechanism for this observation, sigma subunit was purified and an antiserum against sigma subunit was prepared. immunoprecipitation of rna polymerase by the anti-core rna polymerase antiserum, followed by immunoblotting with anti-sigma subunit antibody, revealed that sigma subunit was lost from rna polymerase within 10 minutes after xp10 infection. loss ... | 1998 | 9595658 |
| novel genomic locus with atypical g+c content that is required for extracellular polysaccharide production and virulence in xanthomonas oryzae pv. oryzae. | three exopolysaccharide (eps)- and virulence-deficient mutants of xanthomonas oryzae pv. oryzae, the causal agent of bacterial leaf blight of rice, were isolated by tn5 mutagenesis. these insertions are not located within the gum gene cluster. a 40-kb cosmid clone that restored eps production and virulence to all three mutants was isolated, and the three transposon insertions were localized to contiguous 4.3- and 3.5-kb ecori fragments that are included in this clone. sequence data indicate that ... | 2001 | 11763133 |
| vascular defense responses in rice: peroxidase accumulation in xylem parenchyma cells and xylem wall thickening. | the rice bacterial blight pathogen xanthomonas oryzae pv. oryzae is a vascular pathogen that elicits a defensive response through interaction with metabolically active rice cells. in leaves of 12-day-old rice seedlings, the exposed pit membrane separating the xylem lumen from the associated parenchyma cells allows contact with bacterial cells. during resistant responses, the xylem secondary walls thicken within 48 h and the pit diameter decreases, effectively reducing the area of pit membrane ex ... | 2001 | 11768536 |
| two novel type iii-secreted proteins of xanthomonas campestris pv. vesicatoria are encoded within the hrp pathogenicity island. | the hrp type iii protein secretion system (ttss) is essential for pathogenicity of gram-negative plant pathogen xanthomonas campestris pv. vesicatoria. cdna-amplified fragment length polymorphism and reverse transcription-pcr analyses identified new genes, regulated by key hrp regulator hrpg, in the regions flanking the hrp gene cluster. sequence analysis revealed genes encoding hpag, a predicted leucine-rich repeat-containing protein, the lysozyme-like hpah protein, and xopa and xopd, which are ... | 2002 | 11844763 |
| a 3.1-kb genomic fragment of bacillus subtilis encodes the protein inhibiting growth of xanthomonas oryzae pv. oryzae. | to clone genes of bacillus subtilis encoding peptides that inhibit the growth of xanthomonas orzae pv. oryzae (xoo). | 2001 | 11851812 |
| effect of phenol on protein and amino acid content of xanthomonas oryzae pv. oryzae. | leaf blight disease of rice (oryza sativa) is caused by the bacterium xanthomonas oryzae pv. oryzae. phenol (1 to 4 mm) induced changes in protein profiles of x. o. pv. oryzae and a stress protein with a molecular mass of 69,000 appeared. hplc analysis indicated occurrence of amino acids such as asparagine, alanine, methionine and cystine in phenol treated cells. proton nmr analysis also revealed variation on the presence of amino acids in the cells treated with phenol. | 2001 | 11883515 |
| effect of phenol on lipid and fatty acid profile of xanthomonas oryzae pv. oryzae. | effect of phenol on total lipid and fatty acid composition of xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight of rice (oryzae sativa) was studied. lipid level was low in phenol treated cells. number of fatty acids detected from phenol treated cells was more than those found in untreated cells as revealed by gas chromatography. pentadecanoic acid (c15:0), linolenic acid (c18:3) and behenic acid (c22:0) were present only in the treated cells. palmitic acid which is usually foun ... | 2001 | 11883516 |
| [identification of a resistance gene to bacterial blight (xanthomonas oryzae pv. oryzae) in a somaclonal mutant hx-3 of indica rice]. | using the mature embryo of a susceptible rice variety minghui 63 as the explant, we have obtained a somaclonal mutant hx-3 through selection in vitro, which has showed resistance to bacterial blight. in 8 successive years, the resistance of r1 to r9 generations of hx-3 was identified by zj173, a typical bacterial blight strain in yangtsu river valley, and the results showed that the resistance of hx-3 was stable and heritable. genetic analysis also indicated that the resistance of hx-3 to bacter ... | 2002 | 11901997 |
| the xanthomonas oryzae pv. lozengeoryzae raxp and raxq genes encode an atp sulphurylase and adenosine-5'-phosphosulphate kinase that are required for avrxa21 avirulence activity. | xanthomonas oryzae pv. oryzae (xoo) philippine race 6 (pr6) is unable to cause bacterial blight disease on rice lines containing the rice resistance gene xa21 but is virulent on non-xa21 rice lines, indicating that pr6 carries avirulence (avrxa21) determinants required for recognition by xa21. here we show that two xoo genes, raxp and raxq, are required for avrxa21 activity. raxp and raxq, which reside in a genomic cluster of sulphur assimilation genes, encode an atp sulphurylase and aps (adenos ... | 2002 | 11967067 |
| rpff mutants of xanthomonas oryzae pv. oryzae are deficient for virulence and growth under low iron conditions. | xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. in the related bacterium xanthomonas campestris pv. campestris, the rpff gene is involved in production of a diffusible extracellular factor (dsf) that positively regulates synthesis of virulence-associated functions like extracellular polysaccharide (eps) and extracellular enzymes. transposon insertions in the rpff homolog of x. oryzae pv. oryzae are deficient for virulence and production of a dsf but are pro ... | 2002 | 12036277 |
| genetic locus encoding functions involved in biosynthesis and outer membrane localization of xanthomonadin in xanthomonas oryzae pv. oryzae. | xanthomonadins are membrane-bound, brominated, aryl-polyene pigments specific to the genus xanthomonas. we have characterized a genetic locus (pig) from xanthomonas oryzae pv. oryzae which contains four open reading frames (orfs) that are essential for xanthomonadin production. three of these orfs are homologous to acyl carrier proteins, dehydratases, and acyl transferases, suggesting a type ii polyketide synthase pathway for xanthomonadin biosynthesis. the fourth orf has no homologue in the dat ... | 2002 | 12057948 |
| changes in the plasma membrane distribution of rice phospholipase d during resistant interactions with xanthomonas oryzae pv oryzae. | phospholipase d (pld; ec 3.1.4.4), which hydrolyzes phospholipids to generate phosphatidic acid, was examined in rice leaves undergoing susceptible or resistant interactions with xanthomonas oryzae pv oryzae. rna analysis of leaves undergoing resistant interactions revealed different expression patterns for pld over 5 days relative to control plants or those undergoing susceptible interactions. by using an activity assay and immunoblot analysis, we identified three forms of pld (1, 2, and 3). pl ... | 1996 | 12239412 |
| fine genetic mapping and physical delimitation of the lesion mimic gene spl11 to a 160-kb dna segment of the rice genome. | the rice lesion mimic mutant spl11 was previously found to confer broad-spectrum disease resistance to both magnaporthe grisea and xanthomonas oryzae pv. oryzae. to better understand the molecular basis underlying cell death and disease resistance in rice, a map-based cloning strategy has been employed to isolate spl11. five spl11-linked rapd markers were developed and four of them were mapped to rice chromosome 12. a high-resolution genetic map was developed using a segregating population consi ... | 2002 | 12395200 |
| a high-molecular-weight outer membrane protein of xanthomonas oryzae pv. oryzae exhibits similarity to non-fimbrial adhesins of animal pathogenic bacteria and is required for optimum virulence. | transposon insertions in a novel 3.798 kb open reading frame (orf) of the rice pathogen, xanthomonas oryzae pv. oryzae (xoo) cause virulence deficiency and altered colony/lawn morphology. this orf encodes a protein, xada, of 1,265 amino acids that exhibits significant similarity to non-fimbrial adhesins of animal pathogenic bacteria such as yersinia yada and moraxella uspa1. an interesting feature is that the yada similarity region is repeated six times within the xada sequence and encompasses a ... | 2002 | 12410822 |
| molecular determinants of disease and resistance in interactions of xanthomonas oryzae pv. oryzae and rice. | xanthomonas oryzae pv. oryzae is the causal agent of rice bacterial blight disease. numerous genes critical for virulence have been identified. this article reviews current knowledge on the molecular mechanisms of x. oryzae pv. oryzae virulence. | 2002 | 12443901 |
| [activities of superoxide dismutase in xanthomonas oryzae pv. oryzae and its induction]. | the activities of superoxide dismutase(sod) in xanthomonas oryzae pv. oryzae were determined to demonstrate the correlation of sod activities with the bacterial virulence. in liquid culture, sod activities of the tested strains reached the maxima at the end of lag phase and then declined. the virulent strain pxo99a showed higher sod activities than the avirulent strain pxo99a (pbuavr xa10.f1). analysis on the subcellular location indicated that sod activities detected from the cytoplasm and peri ... | 2000 | 12548996 |
| [purification and partial characterization of antagonistic proteins from bacillus subtilis b034]. | bacillus subtilis b034, an antagonistic bacteria isolated from the phyllosphere of rice, strongly inhibits the growth of xanthomonas oryzae pv. oryzae which causes the rice bacterial blight. crude extract was obtained by precipitation of the cell-free culture of b034 with 70% saturated (nh4)2so4. the suspension of the precipitate strongly inhibits xanthomonas oryzae pv. o-ryzae, and it is thermostable, resistant to trypsin, partial sensitive to proteinase k, pronase e and chloroform. its active ... | 1999 | 12555573 |
| pyramiding transgenes for multiple resistance in rice against bacterial blight, yellow stem borer and sheath blight. | here we describe the development of transgene-pyramided stable elite rice lines resistant to disease and insect pests by conventional crossing of two transgenic parental lines transformed independently with different genes. the xa21 gene (resistance to bacterial blight), the bt fusion gene (for insect resistance) and the chitinase gene (for tolerance of sheath blight) were combined in a single rice line by reciprocal crossing of two transgenic homozygous ir72 lines. f4 plant lines carrying all t ... | 2002 | 12582865 |
| identification of a 47-kb dna fragment containing xa4, a locus for bacterial blight resistance in rice. | bacterial blight caused by xanthomonas oryzae pv oryzae is a devastating disease in rice worldwide. the resistance gene xa4 has been widely used in breeding programs and played an important role in protecting rice from this disease. using 642 highly susceptible individuals and a random sample of 255 individuals from an f(2) population developed from a cross between irbb4 and ir24, the xa4 gene was genetically mapped to a region less than 1 cm. a contig map was constructed for the xa4 region cons ... | 2003 | 12595998 |
| brassinosteroid functions in a broad range of disease resistance in tobacco and rice. | brassinolide (bl), considered to be the most important brassinosteroid (br) and playing pivotal roles in the hormonal regulation of plant growth and development, was found to induce disease resistance in plants. to study the potentialities of bl activity on stress responding systems, we analyzed its ability to induce disease resistance in tobacco and rice plants. wild-type tobacco treated with bl exhibited enhanced resistance to the viral pathogen tobacco mosaic virus (tmv), the bacterial pathog ... | 2003 | 12609030 |
| high resolution genetic mapping and candidate gene identification at the xa5 locus for bacterial blight resistance in rice ( oryza sativa l.). | the xa5 resistance gene from rice provides recessive, race-specific resistance to bacterial blight of rice caused by the pathogen xanthomonas oryzae pv oryzae. a high-resolution genetic map of the chromosomal region surrounding xa5 was developed by placing 44 dna markers on the distal end of rice chromosome 5. the basis for mapping was a pcr-based screening of 1,016 f(2) individuals derived from a cross between a near-isogenic line (nil) and its corresponding recurrent parent to identify recombi ... | 2003 | 12677405 |
| three types of defense-responsive genes are involved in resistance to bacterial blight and fungal blast diseases in rice. | bacterial blight and fungal blast diseases of rice, caused by xanthomonas oryzae pv. oryzae and pyricularia grisea sacc., respectively, are two of the most devastating diseases in rice worldwide. to study the defense responses to infection with each of these pathogens, expression profiling of 12 defense-responsive genes was performed using near-isogenic rice lines that are resistant or susceptible to bacterial blight and fungal blast, respectively, and rice cultivars that are resistant or suscep ... | 2003 | 12684879 |
| compositional difference of the exopolysaccharides produced by the virulent and virulence-deficient strains of xanthomonas oryzae pv. oryzae. | xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, is known to produce phytotoxic polysaccharides. the extracellular polysaccharide (eps) was isolated from virulent (bxo1) and virulence-deficient gum g mutant (bxo1002) strains of x. oryzae pv. oryzae and characterized using fourier transform infrared (ft-ir) and nuclear magnetic resonance (nmr). data from the ft-ir suggested that the aldehyde (r-cho) group and c=o of acid anhydride are present in bxo1 but absent in bxo1002. th ... | 2003 | 12732972 |
| genetic and physical mapping of a new gene for bacterial blight resistance in rice. | the inheritance of resistance for bacterial blight, caused by xanthomonas oryzae pv. oryzae ( xoo), was studied in minghui 63, an elite restorer line for a number of widely used rice hybrids in china. a new dominant gene against a chinese xoo strain jl691 in both the seedling and adult stages was identified in minghui 63 and designated as xa26( t). using a total of 477 highly susceptible individuals from an f(2) population, the xa26( t) locus was mapped to a region of about 1.68 cm. this locus c ... | 2003 | 12750790 |
| high-quality mutant libraries of xanthomonas oryzae pv. oryzae and x. campestris pv. campestris generated by an efficient transposon mutagenesis system. | a novel transposon mutagenesis system for the phytopathogenic bacteria xanthomonas oryzae pv. oryzae (xoo) and x. campestris pv. campestris (xcc) was developed using a tn5-based transposome. a highly efficient transformation up to 10(6) transformants per microg transposon dna was obtained. southern blot and thermal asymmetric interlaced polymerase chain reaction analyses of tn5 insertion sites suggested a random mode of transposition. the transposition was stable in the transformants for 20 subc ... | 2003 | 13129620 |
| isolation and characterization of rice mutants compromised in xa21-mediated resistance to x. oryzae pv. oryzae. | the rice gene, xa21, confers resistance to diverse races of xanthomonas oryzae pv. oryzae (xoo) and encodes a receptor-like kinase with leucine-rich repeats in the extra-cellular domain. to identify genes essential for the function of the xa21 gene, 4,500 irbb21 ( xa21 isogenic line in ir24 background) mutants, induced by diepoxybutane and fast neutrons, were screened against philippine race six (pr6) xoo for a change from resistance to susceptibility. from two greenhouse screens, 23 mutants wer ... | 2004 | 14523518 |
| dna markers and marker-assisted breeding for durable resistance to bacterial blight disease in rice. | bacterial leaf blight caused by the bacterial pathogen xanthomonas oryzae pv oryzae (xoo) limits rice yield in all major rice-growing regions of the world, especially in irrigated lowland and rainfed conditions where predisposition factors favor disease development to epidemic proportions. since bacterial pathogens are difficult to manage, development of host plant resistance is the most effective means of disease management. as many as 24 major genes conferring resistance to various races of th ... | 2002 | 14538061 |
| phya, a secreted protein of xanthomonas oryzae pv. oryzae, is required for optimum virulence and growth on phytic acid as a sole phosphate source. | xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. we have identified a novel virulence deficient mutant (bxo1691) of x. oryzae pv. oryzae that has a tn5 insertion in an open reading frame (phya; putative phytase a) encoding a 373-amino acid (aa) protein containing a 28-aa predicted signal peptide. extracellular protein profiles revealed that a 38-kda band is absent in phya mutants as compared with phya+ strains. a blast search with phya and its deduced polype ... | 2003 | 14601665 |
| xa26, a gene conferring resistance to xanthomonas oryzae pv. oryzae in rice, encodes an lrr receptor kinase-like protein. | rice bacterial blight, caused by xanthomonas oryzae pv. oryzae (xoo), is one of the most serious rice diseases worldwide. a rice gene, xa26, conferring resistance against xoo at both seedling and adult stages was isolated by map-based cloning strategies from the rice cultivar minghui 63. xa26 belongs to a multigene family consisting of four members. it encodes a leucine-rich repeat (lrr) receptor kinase-like protein and is constitutively expressed. sequence analysis revealed that irbb3 and zhach ... | 2004 | 14756760 |
| overexpression of (at)npr1 in rice leads to a bth- and environment-induced lesion-mimic/cell death phenotype. | systemic acquired resistance (sar) is an inducible defense response that protects plants against a broad spectrum of pathogens. a central regulator of sar in arabidopsis is npr1 (nonexpresser of pathogenesis-related genes). in rice, overexpression of arabidopsis npr1 enhances plant resistance to the bacterial pathogen xanthomonas oryzae pv. oryzae. this report demonstrates that overexpression of (at)npr1 in rice also triggers a lesion-mimic/cell death (lmd) phenotype. the lmd phenotype is enviro ... | 2004 | 14964528 |
| evidence for hrpxo-dependent expression of type ii secretory proteins in xanthomonas oryzae pv. oryzae. | xanthomonas oryzae pv. oryzae is a causal agent of bacterial leaf blight of rice. recently, an efficient hrp-inducing medium, xom2, was established for this bacterium. in this medium, more than 10 proteins were secreted from the wild-type strain of x. oryzae pv. oryzae. many of these proteins disappeared or decreased in amount in culture on xom2 when incubated with the strain that has a mutation in the hrp regulatory gene. interestingly, the secretory protein profile of a mutant lacking a type i ... | 2004 | 14973015 |
| molecular characterization of a pathogenesis-related protein 8 gene encoding a class iii chitinase in rice. | a cdna encoding a class iii chitinase (oschib1) was isolated from a cdna library constructed from rice leaves infected with the blast fungus magnaporthe grisea. the cdna contains an open reading frame of 861 nucleotides encoding 286 amino acid residues with a pi of 5.06. the deduced amino acid sequence of oschibl has a high level of similarity with class iiib chitinases of gladiolus gandavensis (46%) and tulipa bakeri (49%). a high level of oschibl mrna was detected after inoculation with m. gri ... | 2004 | 15055541 |
| effect of phenol on ultra structure and plasmid dna of xanthomonas oryzae pv. oryzae. | most phenolic substances of plant origin are toxic to microorganisms and they confer some degree of protection to plants against phytopathogens. xanthomonas oryzae pv. oryzae, bacterial blight pathogen of rice (oryza sativa) was treated with phenol (monohydroxy benzene) and its effects on the morphology and cytological changes of the bacterium were studied. total lysis of cells occurred with 5 mm conc of phenol while at 2 mm conc, the cell walls became rough and cell contents started shrinking. ... | 2003 | 15267140 |
| high-resolution genetic mapping of xa27(t), a new bacterial blight resistance gene in rice, oryza sativa l. | bacterial blight of rice, caused by xanthomonas oryzae pv. oryzae ( xoo) (ishyama) dye, is one of the serious diseases prevalent throughout asia. in a previous study, a resistance ( r) locus was transferred from the tetraploid wild rice oryza minuta to the cultivated rice species, oryza sativa l. here, we report the fine genetic mapping of the r locus, tentatively designated as xa27(t). we performed disease evaluation with an xa27(t) near-isogenic line, irbb27, testing 35 xoo strains collected f ... | 2004 | 15118822 |
| raxh/raxr: a two-component regulatory system in xanthomonas oryzae pv. oryzae required for avrxa21 activity. | xanthomonas oryzae pv. oryzae is the causal agent of bacterial leaf blight, one of the most serious diseases in rice. x. oryzae pv. oryzae philippine race 6 (pr6) strains are unable to establish infection in rice lines expressing the resistance gene xa21. although the pathogen-associated molecule that triggers the xa21-mediated defense response (avrxa21) is unknown, six rax (required for avrxa21 activity) genes encoding proteins involved in sulfur metabolism and type i secretion were recently id ... | 2004 | 15195943 |
| bacterial genes involved in type i secretion and sulfation are required to elicit the rice xa21-mediated innate immune response. | innate immunity to microorganisms relies on the specific sensing of pathogen-associated molecules by host recognition receptors. whereas studies in animals have largely focused on the recognition of extracellular pathogen-associated molecules by the tlr (toll-like receptor) superfamily, few studies have been carried out in plants, and it is not understood how these molecules are secreted or modified. the rice xa21 gene encodes a receptor-like kinase that provides immunity against strains of the ... | 2004 | 15195942 |
| diverse members of the avrbs3/ptha family of type iii effectors are major virulence determinants in bacterial blight disease of rice. | avrxa7 is a member of the avbs3/ptha gene family and the only known type iii secretion system effector gene from xanthomonas oryzae pv. oryzae with a major contribution to bacterial growth and lesion formation in bacterial blight disease of rice. we examined the general requirement for effectors of the avrbs3/ptha family in bacterial blight of rice by identifying effectors from diverse strains of the pathogen. inactivation of single effector genes in representative strains from japan, korea, and ... | 2004 | 15553245 |
| the rice bacterial blight resistance gene xa5 encodes a novel form of disease resistance. | the rice xa5 gene for disease resistance to xanthomonas oryzae pv. oryzae has been positionally cloned and encodes the gamma subunit of transcription factor iia (tfiiagamma). tfiiagamma is a general eukaryotic transcription factor with no previously known role in disease resistance. xa5 is unusual in that it is recessive and does not conform to one of the typical resistance gene structural classes. sequencing of tfiiagamma in resistant and susceptible isolines revealed two nucleotide substitutio ... | 2004 | 15597740 |
| [physiological and genetic analysis of lesion resembling disease mutants (lrd) of oryza sativa l]. | ten indica rice and eight japonica rice mutants with lesion resembling disease (lrd27-44) were obtained by gamma-ray mutagenesis of the whole genomes. these mutants exhibited diverse lesion mimic phenotypes under different growth environments, could be accordingly classified two types, sensitive and insensitive to environments. basing on difference in development of lesion mimics, they can be divided into three categories: whole life lesion mimics (wllm), vegetative initiation lesion mimics (vil ... | 2004 | 15599031 |
| enhanced expression of a gene encoding a nucleoside diphosphate kinase 1 (osndpk1) in rice plants upon infection with bacterial pathogens. | a cdna library was constructed using mrna extracted from rice leaves infected with xanthomonas oryzae pv. oryzae (xoo), a bacterial leaf blight pathogen, to isolate rice genes induced by xoo infection. subtractive hybridization and differential screening of the cdna library led to the isolation of many induced genes including a nucleotide diphosphate kinase 1 (osndpk1) and a pathogenesis-related protein 1 (ospr1) cdna. nucleoside diphosphate kinases (ndpks) are key metabolic enzymes that maintai ... | 2004 | 15650338 |
| characterization of a novel plant growth-promoting bacteria strain delftia tsuruhatensis hr4 both as a diazotroph and a potential biocontrol agent against various plant pathogens. | a novel, plant growth-promoting bacterium delftia tsuruhatensis, strain hr4, was isolated from the rhizoplane of rice (oryza sativa l., cv. yueguang) in north china. in vitro antagonistic assay showed this strain could suppress the growth of various plant pathogens effectively, especially the three main rice pathogens (xanthomonas oryzae pv. oryzae, rhizoctonia solani and pyricularia oryzae cavara). treated with strain hr4 culture, rice blast, rice bacterial blight and rice sheath blight for cv. ... | 2005 | 15709367 |
| avoidance of host recognition by alterations in the repetitive and c-terminal regions of avrxa7, a type iii effector of xanthomonas oryzae pv. oryzae. | avrxa7 is a member of the avrbs3/ptha gene family. the gene is a critical type iii effector in several strains of xanthomonas oryzae pv. oryzae (virulence activity), and in the presence of the xa7 host gene for resistance, controls the elicitation of resistance in rice (avirulence activity). the ability of strains containing avrxa7 to adapt to the presence of xa7 in the host population is dependent, in part, on the genetic plasticity of avrxa7. the potential for the conversion of avrxa7 to a vir ... | 2005 | 15720083 |
| cloning and characterization of a novel avirulence gene (arp3) from xanthomonas oryzae pv. oryzae. | a novel avirulence gene was cloned from xanthomonas oryzae pv. oryzae strain px0339, which is the standard representative of the philippines race 9a. the full-length gene spans 2118 bp and encodes a protein of 705 amino acids. blast search in ncbi indicated that the gene belongs to avrbs3 gene family, and designated arp3 (avrbs3-related protein 3, arp3). the central region of the arp3 contains only 5.5 copies of 102bp repeats, the smallest copy number of repeats found in avrbs3 gene family by no ... | 2004 | 15346765 |
| variation suggestive of horizontal gene transfer at a lipopolysaccharide (lps) biosynthetic locus in xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen of rice. | in animal pathogenic bacteria, horizontal gene transfer events (hgt) have been frequently observed in genomic regions that encode functions involved in biosynthesis of the outer membrane located lipopolysaccharide (lps). as a result, different strains of the same pathogen can have substantially different lps biosynthetic gene clusters. since lps is highly antigenic, the variation at lps loci is attributed to be of advantage in evading the host immune system. although lps has been suggested as a ... | 2004 | 15473911 |
| [mapping of a new resistance gene to bacterial blight in rice line introgressed from oryza officinalis]. | rice line 'b5', which was derived from the wild rice oryza officinalis wall ex watt through introgression, has been proved to be high resistant to brown planthopper, whitebacked planthopper and bacterial blight (xanthomonas oryzae pv. oryzae). in this study, the resistance to bacterial blight of 187 recombinant inbred lines (rils) from a cross between ' b5' and 'minghui63' were evaluated and rflp markers linked to the resistance gene were identified by bulked segregant analysis. analysis of the ... | 2004 | 15473325 |