| 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 .
| | Journal: Plant Cell 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 . | |
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| Title: Plant disease resistance genes encode members of an ancient and diverse protein family within the nucleotide-binding superfamily .
| | Journal: Plant J 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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| Title: Predicting durability of a disease resistance gene based on an assessment of the fitness loss and epidemiological consequences of avirulence gene mutation .
| | Journal: Proc . Natl . Acad . Sci . USA 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 . | |
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| Title: [ Construction of a deep coverage rice BAC library and identification of clones associated with disease-resistant genes ] | | Journal: Yi Chuan Xue Bao 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 . | |
Score: 2.00 |
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| Title: Marker assisted selection of bacterial blight resistance genes in rice .
| | Journal: Biochem . Genet . 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 . | |
