| 92 matches found in 40 documents. Search time: 0.004 seconds. |
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| Title: The C terminus of AvrXa10 can be replaced by the transcriptional activation domain of VP16 from the herpes simplex virus .
| | Author: Zhu W Yang B Wills N Johnson LB White FF .
| | Journal: Plant Cell Citation: V : 11 ( 9 ) P : 1665-74 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10488234 Accession (PMID): 10488234 | | Abstract: 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 domain from the herpes virus protein VP16 restored the ability of the bacteria expressing the hybrid protein to elicit a resistance reaction .
Elicitation was specific for Xa10 , and the reaction had the hallmarks of the response to AvrXa10 .
The results indicate that a domain with the properties of a transcriptional activator plays a critical role in AvrXa10 function .
The results also indicate that the protein has the potential to interact with the plant transcriptional program , although a role for the domain in the stability or conformation of the protein in the plant can not be excluded .
In a broader sense , the transcriptional activation domain of avrXa10 may represent a prokaryotic version of the acidic transcriptional activation domain , which heretofore has been found exclusively in eukaryotes . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: 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 .
[ Sen. 5, subscore: 1.00 ]: Elicitation was specific for Xa10 , and the reaction had the hallmarks of the response to AvrXa10 .
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| Title: Plant disease resistance genes encode members of an ancient and diverse protein family within the nucleotide-binding superfamily .
| | Author: Meyers BC Dickerman AW Michelmore RW Sivaramakrishnan S Sobral BW Young ND .
| | Journal: Plant J Citation: V : 20 ( 3 ) P : 317-32 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10571892 Accession (PMID): 10571892 | | Abstract: The nucleotide binding site ( NBS ) is a characteristic domain of many plant resistance gene products .
An increasing number of NBS-encoding sequences are being identified through gene cloning , PCR amplification with degenerate primers , and genome sequencing projects .
The NBS domain was analyzed from 14 known plant resistance genes and more than 400 homologs , representing 26 genera of monocotyledonous , dicotyle-donous and one coniferous species .
Two distinct groups of diverse sequences were identified , indicating divergence during evolution and an ancient origin for these sequences .
One group was comprised of sequences encoding an N-terminal domain with Toll/Interleukin-1 receptor homology ( TIR ) , including the known resistance genes , N , M , L6 , RPP1 and RPP5 .
Surprisingly , this group was entirely absent from monocot species in searches of both random genomic sequences and large collections of ESTs .
A second group contained monocot and dicot sequences , including the known resistance genes , RPS2 , RPM1 , I2 , Mi , Dm3 , Pi-B , Xa1 , RPP8 , RPS5 and Prf .
Amino acid signatures in the conserved motifs comprising the NBS domain clearly distinguished these two groups .
The Arabidopsis genome is estimated to contain approximately 200 genes that encode related NBS motifs ; TIR sequences were more abundant and outnumber non-TIR sequences threefold .
The Arabidopsis NBS sequences currently in the databases are located in approximately 21 genomic clusters and 14 isolated loci .
NBS-encoding sequences may be more prevalent in rice .
The wide distribution of these sequences in the plant kingdom and their prevalence in the Arabidopsis and rice genomes indicate that they are ancient , diverse and common in plants .
Sequence inferences suggest that these genes encode a novel class of nucleotide-binding proteins .
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[ Sen. 7, subscore: 1.00 ]: A second group contained monocot and dicot sequences , including the known resistance genes , RPS2 , RPM1 , I2 , Mi , Dm3 , Pi-B , Xa1 , RPP8 , RPS5 and Prf .
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| Title: Predicting durability of a disease resistance gene based on an assessment of the fitness loss and epidemiological consequences of avirulence gene mutation .
| | Author: Vera Cruz CM Bai J Ona I Leung H Nelson RJ Mew TW Leach JE .
| | Journal: Proc . Natl . Acad . Sci . USA Citation: V : 97 ( 25 ) P : 13500-5 Year: 2000 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11095723 Accession (PMID): 11095723 | | Abstract: 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 virulence on near-isogenic rice lines with single R genes ( Xa7 , Xa10 , and Xa4 ) at two field sites endemic for bacterial blight .
Disease severity was high in all 3 years on all lines except the line with Xa7 .
Of two Xoo lineages ( groups of strains inferred to be clonally related based on DNA fingerprinting ) detected , one , lineage C , dominated the pathogen population at both sites .
All Xoo strains were virulent to Xa4 , whereas only lineage C strains were virulent to Xa10 .
Only a few strains of lineage C were virulent to Xa7 .
Adaptation to virulence on Xa7 occurred through at least four different pathways and was associated with a reduction in aggressiveness .
Loss of avirulence and reduced aggressiveness were associated with mutations at the 3 terminus of the avrXa7 allele .
Strains most aggressive to Xa7 were not detected after the second year , suggesting they were less persistent than less aggressive strains .
These experiments support the prediction that Xa7 would be a durable R gene because of a fitness penalty in Xoo associated with adaptation to Xa7 . | Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: We evaluated the cost in pathogenic fitness ( aggressiveness and persistence ) associated with adaptation of Xoo to virulence on near-isogenic rice lines with single R genes ( Xa7 , Xa10 , and Xa4 ) at two field sites endemic for bacterial blight .
[ Sen. 6, subscore: 1.00 ]: All Xoo strains were virulent to Xa4 , whereas only lineage C strains were virulent to Xa10 .
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| Title: [ Construction of a deep coverage rice BAC library and identification of clones associated with disease-resistant genes ] | | Author: Wang WM Jiang GH Wang SQ Zhu LH Zhai WX .
| | Journal: Yi Chuan Xue Bao Citation: V : 28 ( 2 ) P : 120-8 Year: Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11233255 Accession (PMID): 11233255 | | Abstract: A BAC library for IRBB56 , an accession pyramiding Xa4 , xa5 and xa13 three bacterial blight resistance genes , was constructed .
The library contains 55 , 296 clones with an average insert size of 132 kb .
Based on a haploid genome size of 450 Mb , the coverage of the library was about 14 genome equivalents that make it one of the most comprehensive BAC libraries available in rice and provide 99 . 99% possibility to isolate any interested rice genes or sequences in the library .
To determine the representation of organelle DNA homologues in the library , the library was screened with three different chloroplast genes and four mitochondrial genes , respectively .
Results from this screening showed that less than 1% of clones in the library contain organelle genomic DNA homologues .
Then , DNA markers on three different chromosomes linked to Xa4 , xa5 , and xa13 , and a PCR fragment of rice UROD gene , were used to screen the library resulting in a range of 11-106 hits that will promote the isolation of these genes .
The deep coverage and the large insert size of the library will facilitate physical mapping , isolation , and cloning of rice genes . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: A BAC library for IRBB56 , an accession pyramiding Xa4 , xa5 and xa13 three bacterial blight resistance genes , was constructed .
[ Sen. 6, subscore: 1.00 ]: Then , DNA markers on three different chromosomes linked to Xa4 , xa5 , and xa13 , and a PCR fragment of rice UROD gene , were used to screen the library resulting in a range of 11-106 hits that will promote the isolation of these genes .
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| Title: Marker assisted selection of bacterial blight resistance genes in rice .
| | Author: Davierwala AP Reddy AP Lagu MD Ranjekar PK Gupta VS .
| | Journal: Biochem . Genet . Citation: V : 39 ( 7-8 ) P : 261-78 Year: 2001 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11590832 Accession (PMID): 11590832 | | Abstract: 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 genes .
Eight lines were found to contain the xa5 gene while two lines contained Xa21 gene and none of the lines contained the xa13 gene with the exception of its near-isogenic line .
Using the polymorphic markers obtained in the initial survey , marker-assisted selection was performed in the F3 population of a cross between IR-64 and IET-14444 to detect lines containing multiple resistance genes .
Of the 59 progeny lines analyzed , eight lines contained both the resistance genes , xa5 and Xa4 . | Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: 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 genes .
[ Sen. 4, subscore: 1.00 ]: Eight lines were found to contain the xa5 gene while two lines contained Xa21 gene and none of the lines contained the xa13 gene with the exception of its near-isogenic line .
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| Title: Are the dominant and recessive plant disease resistance genes similar?
A case study of rice R genes and Xanthomonas oryzae pv . oryzae races .
| | Author: Li ZK Sanchez A Angeles E Singh S Domingo J Huang N Khush GS .
| | Journal: Genetics Citation: V : 159 ( 2 ) P : 757-65 Year: 2001 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11606550 Accession (PMID): 11606550 | | Abstract: 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 avirulent Xoo races .
The quantitative component of the R genes was their residual effects against corresponding virulent races and their epistatic effects , which together could lead to high-level resistance in a race-specific manner .
Our results revealed important differences between the different types of R genes .
Two R genes , Xa4 and Xa21 , showed complete dominance against the avirulent Xoo races and had large residual effects against virulent ones .
They acted independently and cumulatively , suggesting they are involved in different pathways of the rice defensive system .
The third R gene , xa5 , showed partial dominance or additivity to the avirulent Xoo races and had relatively small but significant residual effects against the virulent races .
In contrast , xa13 was completely recessive , had no residual effects against the virulent races , and showed more pronounced race specificity .
There was a strong interaction leading to increased resistance between xa13 and xa5 and between either of them and Xa4 or Xa21 , suggesting their regulatory roles in the rice defensive pathway ( s ) .
Our results indicated that high-level and durable resistance to Xoo should be more efficiently achieved by pyramiding different types of R genes . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: 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 .
[ Sen. 9, subscore: 1.00 ]: In contrast , xa13 was completely recessive , had no residual effects against the virulent races , and showed more pronounced race specificity .
[ Sen. 10, subscore: 1.00 ]: There was a strong interaction leading to increased resistance between xa13 and xa5 and between either of them and Xa4 or Xa21 , suggesting their regulatory roles in the rice defensive pathway ( s ) .
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| Title: [ Activities of superoxide dismutase in Xanthomonas oryzae pv . oryzae and its induction ] | | Author: Song F Ge X Zheng Z Hu X | | Journal: Wei Sheng Wu Xue Bao Citation: V : 40 ( 3 ) P : 301-5 Year: 2000 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12548996 Accession (PMID): 12548996 | | Abstract: 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 periplasm were over 70% and 20%-30% of the total , respectively .
Treatment of the bacterial culture for 1 h with exogenous O2 at concentration of 50-800 mumol/L induced SOD activities of both the strains .
The treatment with 200 mumol/L resulted in the highest SOD activities .
The effect of exogenous O2 on SOD induction was more significant in 12 h-culture than in 24 h-culture , and more notable for the virulent strain PXO99A .
The treatment with exogenous O2 resulted in significantly decreased survival rate off both the strains .
The decreases of survival rate were greater in 24 h-culture than in 12 h-culture , and more significantly for the virulent strain than for the avirulent one . | Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: The virulent strain PXO99A showed higher SOD activities than the avirulent strain PXO99A ( pBUavr Xa10 . F1 ) .
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| Title: High-resolution mapping of the leaf rust disease resistance gene Lr1 in wheat and characterization of BAC clones from the Lr1 locus .
| | Author: Ling HQ Zhu Y Keller B | | Journal: Theor . Appl . Genet . Citation: V : 106 ( 5 ) P : 875-82 Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12647062 Accession (PMID): 12647062 | | Abstract: Leaf rust is the most common disease in wheat production .
There are more than 45 specific resistance genes described and used in wheat breeding to control epidemics of leaf rust , but none of them has been cloned .
The leaf rust disease resistance gene 1 ( Lr1 ) is a good model gene for isolation by map-based cloning because it is a single , dominant gene which is located in the distal region of chromosome 5DL of wheat .
As the first step towards the isolation of this gene we constructed a high-resolution genetic map in the region of the Lr1 locus by saturation mapping of two large segregating F ( 2 ) populations ( Thatcher Lr1 x Thatcher , Thatcher Lr1 x Frisal ) .
The resistance gene Lr1 was delimited in a 0 . 16-cM region between the RFLP markers ABC718 and PSR567 ( 0 . 12 cM from ABC718 and 0 . 04 cM from PSR567 ) .
A genomic BAC library of Aegilops tauschii ( D genome ) was screened using the RFLP markers ABC718 and PSR567 .
Five positive BAC clones were identified by ABC718 and four clones by PSR567 .
Two NBS-LRR type of resistance gene analogs , which encode proteins highly homologous to the bacterial blight disease resistance protein Xa1 of rice , were identified on BAC clones isolated with PSR567 .
Polymorphic BAC end probes were isolated from both ends of a 105-kb large BAC clone identified by ABC718 .
The end probes were mapped at the same locus as ABC718 , and no recombination event was found within 105 kb around ABC718 in our analysis of more than 4 , 000 gametes .
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[ Sen. 8, subscore: 1.00 ]: Two NBS-LRR type of resistance gene analogs , which encode proteins highly homologous to the bacterial blight disease resistance protein Xa1 of rice , were identified on BAC clones isolated with PSR567 .
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| Title: Genome-wide analysis of defense-responsive genes in bacterial blight resistance of rice mediated by the recessive R gene xa13 .
| | Author: Chu Z Ouyang Y Zhang J Yang H Wang S | | Journal: Mol . Genet . Genomics Citation: V : 271 ( 1 ) P : 111-20 Year: 2004 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub14730444 Accession (PMID): 14730444 | | Abstract: Defense responses triggered by dominant and recessive disease resistance ( R ) genes are presumed to be regulated by different molecular mechanisms .
In order to characterize the genes activated in defense responses against bacterial blight mediated by the recessive R gene xa13 , two pathogen-induced subtraction cDNA libraries were constructed using the resistant rice line IRBB13--which carries xa13--and its susceptible , near-isogenic , parental line IR24 .
Clustering analysis of expressed sequence tags ( ESTs ) identified 702 unique expressed sequences as being involved in the defense responses triggered by xa13 ; 16% of these are new rice ESTs .
These sequences define 702 genes , putatively encoding a wide range of products , including defense-responsive genes commonly involved in different host-pathogen interactions , genes that have not previously been reported to be associated with pathogen-induced defense responses , and genes ( 38% ) with no homology to previously described functional genes .
In addition , R-like genes putatively encoding nucleotide-binding site/leucine rich repeat ( NBS-LRR ) and LRR receptor kinase proteins were observed to be induced in the disease resistance activated by xa13 .
A total of 568 defense-responsive ESTs were mapped to 588 loci on the rice molecular linkage map through bioinformatic analysis .
About 48% of the mapped ESTs co-localized with quantitative trait loci ( QTLs ) for resistance to various rice diseases , including bacterial blight , rice blast , sheath blight and yellow mottle virus .
Furthermore , some defense-responsive sequences were conserved at similar locations on different chromosomes .
These results reveal the complexity of xa13-mediated resistance .
The information obtained in this study provides a large source of candidate genes for understanding the molecular bases of defense responses activated by recessive R genes and of quantitative disease resistance . | Matching Sentences:
[ Sen. 2, subscore: 2.00 ]: In order to characterize the genes activated in defense responses against bacterial blight mediated by the recessive R gene xa13 , two pathogen-induced subtraction cDNA libraries were constructed using the resistant rice line IRBB13--which carries xa13--and its susceptible , near-isogenic , parental line IR24 .
[ Sen. 3, subscore: 1.00 ]: Clustering analysis of expressed sequence tags ( ESTs ) identified 702 unique expressed sequences as being involved in the defense responses triggered by xa13 ; 16% of these are new rice ESTs .
[ Sen. 5, subscore: 1.00 ]: In addition , R-like genes putatively encoding nucleotide-binding site/leucine rich repeat ( NBS-LRR ) and LRR receptor kinase proteins were observed to be induced in the disease resistance activated by xa13 .
[ Sen. 9, subscore: 1.00 ]: These results reveal the complexity of xa13-mediated resistance .
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| Title: RaxH/RaxR : a two-component regulatory system in Xanthomonas oryzae pv . oryzae required for AvrXa21 activity .
| | Author: Burdman S Shen Y Lee SW Xue Q Ronald P | | Journal: Mol .
Plant Microbe Interact .
Citation: V : 17 ( 6 ) P : 602-12 Year: 2004 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub15195943 Accession (PMID): 15195943 | | Abstract: 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 identified .
Here , we report on the identification of two additional rax genes , raxR and raxH , which encode a response regulator and a histidine protein kinase of two-component regulatory systems , respectively .
Null mutants of PR6 strain PXO99 that are impaired in either raxR , raxH , or both cause lesions significantly longer and grow to significantly higher levels than does the wild-type strain in Xa21-rice leaves .
Both raxR and raxH mutants are complemented to wild-type levels of AvrXa21 activity by introduction of expression vectors carrying raxR and raxH , respectively .
These null mutants do not affect AvrXa7 and AvrXa10 activities , as observed in inoculation experiments with Xa7 and Xa10-rice lines .
Western blot and raxR/gfp promoter-reporter analyses confirmed RaxR expression in X oryzae pv . oryzae .
The results of promoter-reporter studies also suggest that the previously identified raxSTAB operon is a target for RaxH/RaxR regulation .
Characterization of the RaxH/RaxR system provides new opportunities for understanding the specificity of the X oryzae pv . oryzae-Xa21 interaction and may contribute to the identification of AvrXa21 . | Matching Sentences:
[ Sen. 7, subscore: 1.00 ]: These null mutants do not affect AvrXa7 and AvrXa10 activities , as observed in inoculation experiments with Xa7 and Xa10-rice lines .
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