| 285 matches found in 115 documents. Search time: 0.006 seconds. |
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Score: 11.00 |
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| | Author: Chen X Chern M Canlas PE Jiang C Ruan D Cao P Ronald PC | | Journal: J Biol Chem Year: 2010 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20118235 Accession (PMID): 20118235 | | Abstract: Despite the key role that pattern recognition receptors ( PRRs ) play in regulating immunity in plants and animals , the mechanism of activation of the associated non-arginine-aspartate ( non-RD ) kinases is unknown .
The rice PRR XA21 recognizes the pathogen-associated molecular pattern , Ax21 ( activator of XA21-mediated immunity ) .
Here we show that the XA21 juxtamembrane ( JM ) domain is required for kinase autophosphorylation .
Threonine 705 in the XA21 JM domain is essential for XA21 autophosphorylation in vitro and XA21-mediated innate immunity in vivo .
The replacement of Thr ( 705 ) by an alanine or glutamic acid abolishes XA21 autophosphorylation and eliminates interactions between XA21 and four XA21-binding proteins in yeast and rice .
Although threonine residues analogous to Thr ( 705 ) of XA21 are present in the JM domains of most RD and non-RD plant receptor-like kinases , this residue is not required for autophosphorylation of the Arabidopsis RD RLK BRI1 ( brassinosteroid insensitive 1 ) .
The threonine 705 of XA21 is conserved only in the JM domains of plant RLKs but not in those of fly , human , or mouse suggesting distinct regulatory mechanisms .
These results contribute to growing knowledge regarding the mechanism by which non-RD RLKs function in plant .
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Score: 10.00 |
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| | Author: Chen F Gao MJ Miao YS Yuan YX Wang MY Li Q Mao BZ Jiang LW He ZH | | Journal: Mol Plant Year: 2010 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20616165 Accession (PMID): 20616165 | | Abstract: The rice pattern recognition receptor ( PRR ) XA21 confers race-specific resistance in leaf infection by bacterial blight Xathomonas oryzae pv . oryzae ( Xoo ) , and was shown to be primarily localized to the endoplasmic reticulum ( ER ) when expressed with its native promoter or overexpressed in the protoplast However , whether the protein is still ER-localization in the intact cell when overexpressed remains to be identified .
Here , we showed that XA21 , its kinase-dead mutant XA21P ( K736EP ) , and the triple autophosphorylation mutant XA21P ( S686A/T688A/S699A ) GFP fusions were primarily localized to the plasma membrane ( PM ) when overexpressed in the intact transgenic rice cell , and also localized to the ER in the transgenic protoplast The transgenic plants constitutively expressing the wild-type XA21 or its GFP fusion displayed race-specific resistance to Xoo at the adult and seedling stages .
XA21 and XA21P ( K736EP ) could be internalized probably via the SCAMP-positive early endosomal compartment in the protoplast , suggesting that XA21 might be endocytosed to initiate resistance responses during pathogen infection .
We also established a root infection system and demonstrated that XA21 also mediated race-specific resistance responses to Xoo in the root .
Our current study provides an insight into the nature of the XA21-mediated resistance and a practical approach using the root cell system to further dissect the cellular signaling of the PRR during the rice-Xoo interaction .
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Score: 10.00 |
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| | Author: Tan S Wang D Ding J Tian D Zhang X Yang S | | Journal: Genetica Year: 2011 Type: In-Process | | Literature: oryza Field: abstract Doc ID: pub22451352 Accession (PMID): 22451352 | | Abstract: The XA21 protein has broad spectrum resistance against Xanthomonas oryzae pv . oryzae .
Although Xa21-mediated immunity is well characterized , little is known about the origin and evolutionary history of this gene in grasses .
Therefore , we analyzed all Xa21 gene homologs in eight whole-genome sequenced rice lines , as well as in four gramineous genomes , rice , Brachypodium , sorghum and maize ; using Arabidopsis Xa21 homologs as outgroups , 17 , 7 , 7 and 3 Xa21 homologs were detected in these four grasses , respectively .
Synteny and phylogenetic analysis showed that frequent gene translocation , duplication and/or loss , have occurred at Xa21 homologous loci , suggesting that they have undergone or are undergoing rapid generation of copy number variations .
Within the rice species , the high level of nucleotide diversity between Xa21-like orthologs showed a strong association with the presence/absence haplotypes , suggesting that the genetic structure of rice lines plays an important role in the variations between these Xa21-like orthologs .
Strongly positive selection was detected in the core region of the leucine-rich repeat domains of the Xa21 subclade among the rice lines , indicating that the rapid gene diversification of Xa21 homologs may be a strategy for a given species to adapt to the changing spectrum of species-specific pathogens .
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Score: 9.00 |
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| | Author: Liu GZ Pi LY Walker JC Ronald PC Song WY .
| | Journal: J Biol . Chem . Year: 2002 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11927577 Accession (PMID): 11927577 | | Abstract: The rice disease resistance gene , Xa21 , encodes a receptor kinase-like protein consisting of leucine-rich repeats in the putative extracellular domain and a serine/threonine kinase in the putative intracellular domain .
The putative XA21 kinase domain was expressed as maltose-binding and glutathione S-transferase fusion proteins in Escherichia coli .
The fusion proteins are capable of autophosphorylation .
Phosphoamino acid analysis of the glutathione S-transferase fusion protein indicates that only serine and threonine residues are phosphorylated .
The relative phosphorylation rate of the XA21 kinase against increasing enzyme concentrations follows a first-order rather than second-order kinetics , indicating an intramolecular phosphorylation mechanism .
Moreover , the active XA21 kinase can not phosphorylate a kinase-deficient mutant of XA21 kinase .
The enzymatic activity of the XA21 kinase in a buffer containing Mn ( 2+ ) is at least 15 times higher than that with Mg ( 2+ ) .
The K ( m ) and V ( max ) of XA21 kinase for ATP are 0 . 3 microm and 8 . 4 nmol/mg/min , respectively .
Tryptic phosphopeptide mapping reveals that multiple sites on the XA21 kinase are phosphorylated .
Finally , our data suggest that the region of XA21 kinase corresponding to the RD kinase activation domain is not phosphorylated , revealing a distinct mode of action compared with the tomato Pto serine/threonine kinase conferring disease resistance . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 9.00 |
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| | Author: Wang YS Pi LY Chen X Chakrabarty PK Jiang J De Leon AL Liu GZ Li L Benny U Oard J Ronald PC Song WY .
| | Journal: Year: 2006 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub17172358 Accession (PMID): 17172358 | | Abstract: XA21 is a receptor-like kinase protein in rice ( Oryza sativa ) that confers gene-for-gene resistance to specific races of the causal agent of bacterial blight disease , Xanthomonas oryzae pv oryzae .
We identified XA21 binding protein 3 ( XB3 ) , an E3 ubiquitin ligase , as a substrate for the XA21 Ser and Thr kinase .
The interaction between XB3 and the kinase domain of XA21 has been shown in yeast and in vitro , and the physical association between XB3 and XA21 in vivo has also been confirmed by coimmunoprecipitation assays .
XB3 contains an ankyrin repeat domain and a RING finger motif that is sufficient for its interaction with the kinase domain of XA21 and for its E3 ubiquitin ligase activity , respectively .
Transgenic plants with reduced expression of the Xb3 gene are compromised in resistance to the avirulent race of X oryzae pv oryzae .
Furthermore , reduced levels of Xb3 lead to decreased levels of the XA21 protein .
These results indicate that Xb3 is necessary for full accumulation of the XA21 protein and for Xa21-mediated resistance . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 9.00 |
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| | Author: Park CJ Peng Y Chen X Dardick C Ruan D Bart R Canlas PE Ronald PC | | Journal: PLoS Biol Year: 2008 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub18817453 Accession (PMID): 18817453 | | Abstract: Perception of extracellular signals by cell surface receptors is of central importance to eukaryotic development and immunity .
Kinases that are associated with the receptors or are part of the receptors themselves modulate signaling through phosphorylation events .
The rice ( Oryza sativa L ) XA21 receptor kinase is a key recognition and signaling determinant in the innate immune response .
A yeast two-hybrid screen using the intracellular portion of XA21 , including the juxtamembrane ( JM ) and kinase domain as bait , identified a protein phosphatase 2C ( PP2C ) , called XA21 binding protein 15 ( XB15 ) .
The interaction of XA21 and XB15 was confirmed in vitro and in vivo by glutathione-S-transferase ( GST ) pull-down and co-immunoprecipitation assays , respectively .
XB15 fusion proteins purified from Escherichia coli and from transgenic rice carry PP2C activity .
Autophosphorylated XA21 can be dephosphorylated by XB15 in a temporal and dosage-dependent manner .
A serine residue in the XA21 JM domain is required for XB15 binding .
Xb15 mutants display a severe cell death phenotype , induction of pathogenesis-related genes , and enhanced XA21-mediated resistance .
Overexpression of Xb15 in an XA21 rice line compromises resistance to the bacterial pathogen Xanthomonas oryzae pv . oryzae .
These results demonstrate that Xb15 encodes a PP2C that negatively regulates the XA21-mediated innate immune response .
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Score: 9.00 |
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| | Author: Wang GL Ruan DL Song WY Sideris S Chen L Pi LY Zhang S Zhang Z Fauquet C Gaut BS Whalen MC Ronald PC .
| | Journal: Plant Cell Year: 1998 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9596635 Accession (PMID): 9596635 | | Abstract: 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 transcript terminates shortly after the stop codon introduced by the retrotransposon Retrofit .
Comparison of nucleotide substitutions in the LRR coding regions of Xa21 and Xa21D provided evidence of adaptive selection .
Both functional and evolutionary evidence indicates that the Xa21D LRR domain controls race-specific pathogen recognition . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 8.00 |
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| | Author: Ronald PC Albano B Tabien R Abenes L Wu KS McCouch S Tanksley SD .
| | Journal: Mol . Gen . Genet . Year: 1992 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub1362973 Accession (PMID): 1362973 | | Abstract: 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 Xa21 introgressed region to an 8 . 3 cM interval on chromosome 11 .
Furthermore , we identified two polymerase chain reaction ( PCR ) products ( RAPD2148 and RAPD818 ) that detected polymorphisms between the NILs .
Genomic sequences hybridizing with RAPD818 , RAPD248 and RG103 were duplicated specifically in the Xa21 NIL .
All three markers cosegregated with the resistance locus , Xa21 , in a F2 population of 386 progeny .
Based on the frequency with which we recovered polymorphic Xa21-linked markers , we estimated the physical size of the introgressed region to be approximately 800 kb .
This estimation was supported by physical mapping ( using pulsed field gel electrophoresis ) of the sequences hybridizing with the three Xa21-linked DNA markers .
The results showed that the three Xa21-linked markers are physically close to each other , with one copy of the RAPD818 sequences located within 60 kb of RAPD248 and the other copy within 270 kb of RG103 .
None of the enzymes tested generated a DNA fragment that hybridized with all three of the markers indicating that the introgressed region containing the resistance locus Xa21 is probably larger than 270 kb . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 8.00 |
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| | Author: Wang GL Wu C Zeng L He C Baraoidan M de Assis Goes da Silva F Williams CE Ronald PC Leung H | | Journal: Theor . Appl . Genet . Year: 2004 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub14523518 Accession (PMID): 14523518 | | Abstract: 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 were identified that had changed from resistant to fully ( 6 ) or partially ( 17 ) susceptible to PR6 .
All fully susceptible mutants carried rearrangements at the Xa21 locus as detected by PCR and Southern hybridization .
For the partially susceptible mutants , no changes were detected at the Xa21 locus based on Southern and PCR analyses .
However , two of these mutants were confirmed via genetic analysis to have mutations at the Xa21 locus .
Partially susceptible mutants exhibited variation in level of susceptibility to different Xoo strains , suggesting that they may carry different mutations required for the Xa21-mediated resistance .
The mutants identified in this study provide useful materials for dissecting the Xa21-mediated resistance pathway in rice . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 8.00 |
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| | Author: Zhai W Chen C Zhu X Chen X Zhang D Li X Zhu L | | Journal: Theor . Appl . Genet . Year: 2004 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub15088086 Accession (PMID): 15088086 | | Abstract: The genetic loci and phenotypic effects of the transgene Xa21 , a bacterial blight ( BB ) resistance gene cloned from rice , were investigated in transgenic rice produced through an Agrobacterium-mediated transformation system .
The flanking sequences of integrated T-DNAs were isolated from Xa21 transgenic rice lines using thermal asymmetric interlaced PCR .
Based on the analysis of 24 T-DNA Xa21 flanking sequences , T-DNA loci in rice could be classified into three types : the typical T-DNA integration with the definite left and right borders , the T-DNA integration linked with the adjacent vector backbone sequences and the T-DNA integration involved in a complicated recombination in the flanking sequences .
The T-DNA integration in rice was similar to that in dicotyledonous genomes but was significantly different from the integration produced through direct DNA transformation approaches .
All three types of integrated transgene Xa21 could be stably inherited and expressed the BB resistance through derived generations in their respective transgenic lines .
The flanking sequences of the typical T-DNA integration consisted of actual rice genomic DNA and could be used as probes to locate the transgene on the rice genetic map .
A total of 15 different rice T-DNA flanking sequences were identified .
They displayed restriction fragment length polymorphisms ( RFLPs ) between two rice varieties , ZYQ8 and JX17 , and were mapped on rice chromosomes 1 , 3 , 4 , 5 , 7 , 9 , 10 , 11 and 12 , respectively , by using a double haploid population derived from a cross between ZYQ8 and JX17 .
The blast search and homology comparison of the rice T-DNA flanking sequences with the rice chromosome-anchored sequence database confirmed the RFLP mapping results .
On the basis of genetic mapping of the T-DNA Xa21 loci , the BB resistance effects of the transgene Xa21 at different chromosome locations were investigated using homozygous transgenic lines with only one copy of the transgene .
Among the transgenic lines , no obvious position effects of the transgene Xa21 were observed .
In addition , the BB resistance levels of the Xa21 transgenic plants with different transgene copy numbers and on different genetic backgrounds were also investigated .
It was observed that genetic background ( or genome ) effects were more obvious than dosage effects and position effects on the BB resistance level of the transgenic plants . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 8.00 |
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| | Author: Park CJ Han SW Chen X Ronald PC | | Journal: Cell Microbiol Year: 2010 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20590657 Accession (PMID): 20590657 | | Abstract: In the early 1970s , the Xa21 gene from the wild rice species Oryza longistaminata drew attention of rice breeders because of its broad-spectrum resistance to diverse strains of a serious bacterial disease of rice in Asia and Africa , called bacterial blight disease , caused by the Gram-negative bacterium , Xanthomonas oryzae pv . oryzae ( Xoo ) .
In 1995 , we isolated the gene controlling this resistance and in 2009 demonstrated that XA21 recognizes a highly conserved peptide , called Ax21 ( activator of XA21-mediated immunity ) .
Tyrosine sulfation of Ax21 is required for recognition by rice XA21 .
A decade of genetic , molecular and biochemical studies have uncovered key components of the XA21-mediated signalling cascade .
Ax21 recognition by XA21 at the cell surface induces phosphorylation-mediated events , which are predicted to alter subcellular localization and/or DNA-binding activity of a WRKY family of transcription factors .
Because XA21 is representative of the large number of predicted pattern recognition receptors ( PRRs ) in rice ( n = 328 ) , Arabidopsis ( n = 35 ) and other plant species , further characterization of XA21-mediated signalling pathways will contribute to elucidation of these important defence responses .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 7.00 |
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| | Author: Century KS Lagman RA Adkisson M Morlan J Tobias R Schwartz K Smith A Love J Ronald PC Whalen MC .
| | Journal: Plant J Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10571882 Accession (PMID): 10571882 | | Abstract: 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 juvenile leaf 2 stage through later stages , with 100% resistance at the adult leaf 9/10 stage .
We found that Xa21 expression is independent of plant developmental stage , infection with Xoo , or wounding .
Expression of the Xa21 gene transcript is not correlated with expression of Xa21 disease resistance indicating that the developmental regulation of Xa21-resistance is either controlled post-transcriptionally or by other factors . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 7.00 |
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| | Author: Xu WH Wang YS Liu GZ Chen X Tinjuangjun P Pi LY Song WY .
| | Journal: Plant J Year: 2006 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16460508 Accession (PMID): 16460508 | | Abstract: The rice gene Xa21 confers resistance against Xanthomonas oryzae pv . oryzae ( Xoo ) .
Xa21 encodes a receptor-like kinase ( XA21 ) .
We demonstrate that XA21 autophosphorylates residues Ser686 , Thr688 and Ser689 in vitro .
Substitution of these residues with alanines did not affect the autophosphorylation function of this kinase , but specifically destabilized the resistance protein in vitro and in vivo .
Plants carrying these same substitutions in XA21 were compromised in their resistance to the normally avirulent Xoo Philippine race 6 .
Additionally , we show that wild-type XA21 and the kinase-dead mutant with the invariable Lys736 residue mutated to glutamic acid were also proteolytically degraded in protein extracts .
Finally , we show a correlation between the in vitro degradation and in vivo instability of the proteins .
We propose that autophosphorylation of Ser686 , Thr688 and Ser689 functions to stabilize XA21 against the developmentally controlled proteolytic activity . | | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 7.00 |
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| | Author: Park CJ Lee SW Chern M Sharma R Canlas PE Song MY Jeon JS Ronald PC | | Journal: Plant Sci Year: 2010 Type: In-Data-Review | | Literature: oryza Field: abstract Doc ID: pub21076626 Accession (PMID): 21076626 | | Abstract: Recognition of pathogen-associated molecular patterns ( PAMPs ) by pattern recognition receptors ( PRRs ) activates the innate immune response .
The rice PRR , XA21 , confers robust resistance at adult stages to most strains of the bacterial pathogen Xanthomonas oryzae pv . oryzae ( Xoo ) .
Seedlings are still easily infected by Xoo , causing severe yield losses .
Here we report that Xa21 is induced by Xoo infection and that ectopic expression of Xa21 confers resistance at three leaf stage ( three-week-old ) , overcoming the developmental limitation of XA21-mediated resistance .
Ectopic expression of Xa21 also up-regulates a larger set of defense-related genes as compared to Xa21 driven by the native promoter .
These results indicate that altered regulation of Xa21 expression is useful for developing enhanced resistance to Xoo at multiple developmental stages .
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Score: 6.00 |
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| | Author: Huang TY Li SG Wang YP Li HY .
| | Journal: Sheng Wu Gong Cheng Xue Bao Year: 2003 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub15966313 Accession (PMID): 15966313 | | Abstract: Shuhui527 is a promising restorer line bred by Rice Research Institute of Sichuan Agricultural University in recent years .
However , this line is susceptible to Bacterial Blight ( BB ) , which limits its use .
The IRBB60 , from the International Rice Research Institute ( IRRI ) , contains dominant genes Xa21 and Xa4 conferring resistance to BB .
The objective of this study is to improve the BB resistance of Shuhui527 by introgressing Xa21 and Xa4 , the two broad-spectrum BB resistance genes , into Shuhui527 with IRBB60 as the donor , pTA248 and MP12 , linking tightly with Xa21 and Xa4 respectively as DNA markers .
BC1 F1 progenies of ( Shuhui527 x IRBB60 ) , containing Xa21 and Xa4 identified using PCR screening and with agronomic traits including plant type , grain type and days to heading etc similar to those of Shuhui527 , were subsequently backcrossed to Shuhui527 and self-pollinated to generate BC2 F1 and BC1 F2 . The BC3 F1 and BC3 F2 were subsequently developed using the same approach .
Among the 20 BC3 F2 plants , homozygous Xa21 and Xa4 , 10 plants were the most similar to Shuhui527 in the agronomic traits , and were screened using 120 pairs SSR and 100 pairs RAPD markers .
Based on the results of the background screening and the performance of the agronomic traits , 5 plants were identified as improved-Shuhui527 and designated as 527R-5 , 527R-6 , 527R-8 , 527R-9 and 527R-10 .
The improved- Shuhui527 lines expressed high resistance to Xanthomonas oryzae pv . oryzae ( Xoo ) stains C I - C VII , P1 and P6 .
The evaluation of the polymorphisms and selection accuracies of pTA248 and MP12 demonstrated that the polymorphisms of the two markers were obvious and co-dominant and the accuracies were more than 97% and 83% respectively , indicating the two markers are good for Xa21 and Xa4 in Molecular Marker-assisted Selection .
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Score: 6.00 |
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| | Author: Akimoto K Katakami H Kim HJ Ogawa E Sano CM Wada Y Sano H | | Journal: Ann Bot ( Lond ) Year: 2007 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub17576658 Accession (PMID): 17576658 | | Abstract: BACKGROUND AND AIMS : Epigenetics is defined as mechanisms that regulate gene expression without base sequence alteration .
One molecular basis is considered to be DNA cytosine methylation , which reversibly modifies DNA or chromatin structures .
Although its correlation with epigenetic inheritance over generations has been circumstantially shown , evidence at the gene level has been limited .
The present study aims to find genes whose methylation status directly correlates with inheritance of phenotypic changes .
METHODS : DNA methylation in vivo was artificially reduced by treating rice ( Oryza sativa ssp . japonica ) seeds with 5-azadeoxycytidine , and the progeny were cultivated in the field for > 10 years .
Genomic regions with changed methylation status were screened by the methylation-sensitive amplified polymorphysm ( MSAP ) method , and cytosine methylation was directly scanned by the bisulfite mapping method .
Pathogen infection with Xanthomonas oryzae pv . oryzae , race PR2 was performed by the scissors-dip method on mature leaf blades .
KEY RESULTS : The majority of seedlings were lethal , but some survived to maturity .
One line designated as Line-2 showed a clear marker phenotype of dwarfism , which was stably inherited by the progeny over nine generations .
MSAP screening identified six fragments , among which two were further characterized by DNA blot hybridization and direct methylation mapping .
One clone encoding a retrotransposon gag-pol polyprotein showed a complete erasure of 5-methylcytosines in Line-2 , but neither translocation nor expression of this region was detectable .
The other clone encoded an Xa21-like protein , Xa21G .
In wild-type plants , all cytosines were methylated within the promoter region , whereas in Line-2 , corresponding methylation was completely erased throughout generations .
Expression of Xa21G was not detectable in wild type but was constitutive in Line-2 .
When infected with X oryzae pv . oryzae , against which Xa21 confers resistance in a gene-for-gene manner , the progeny of Line-2 were apparently resistant while the wild type was highly susceptible without Xa21G expression .
CONCLUSIONS : These results indicated that demethylation was selective in Line-2 , and that promoter demethylation abolished the constitutive silencing of Xa21G due to hypermethylation , resulting in acquisition of disease resistance .
Both hypomethylation and resistant trait were stably inherited .
This is a clear example of epigenetic inheritance , and supports the idea of Lamarckian inheritance which suggested acquired traits to be heritable .
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Score: 6.00 |
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| | Author: Wang SL Li LY Shang JJ Wang J Liu GZ | | Journal: Wei Sheng Wu Xue Bao Year: 2007 Type: In-Process | | Literature: oryza Field: abstract Doc ID: pub18271255 Accession (PMID): 18271255 | | Abstract: Rice bacterial blight and blast are the most crucial rice disease .
Xa21 confers resistance to bacterial blight , while Pi-d2 confers resistance to rice blast Both Xa21 and Pi-d2 encode receptor kinase-like proteins .
Biochemical properties of XA21 kinase expressed in bacterial were characterized in our previous report .
In this study , both XA21 and PI-D2 kinase domain were PCR amplified and cloned into yeast expression vector pEGH via recombinational cloning strategy , kinase proteins expressed in eukaryotic yeast system was purified and autophosphorylation assay was carried out .
The results indicated that XA21 and PI-D2 protein can be detected by SDS-PAGE and showed expected molecular weight .
Autophosphorylation assay indicated that yeast expressed XA21 and PI-D2 were active when incubated with P32 labelled ATP .
The experiment provided basic materials for biochemical prosperity analysis , protein-protein interaction and substrate screening research .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 6.00 |
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| | Author: Zhao J Fu J Li X Xu C Wang S | | Journal: Theor Appl Genet Year: 2009 Type: Publisher | | Literature: oryza Field: abstract Doc ID: pub19390838 Accession (PMID): 19390838 | | Abstract: Development-controlled resistance and resistance specificity frequently restrict the application of a disease resistance ( R ) gene in crop breeding programs .
Xa3/Xa26 and Xa21 , encoding leucine-rich repeat ( LRR ) -kinase type plasma membrane proteins , mediate race-specific resistance to Xanthomonas oryzae pv . oryzae ( Xoo ) , which causes bacterial blight , one of the most devastating rice diseases .
Plants carrying Xa3/Xa26 and plants carrying Xa21 have different resistance spectra and the functions of the two R genes are regulated by developmental stage .
Four chimeric genes encoding proteins consisting of different parts of XA3/XA26 and XA21 were constructed by domain swapping and transformed into a susceptible rice variety .
The resistance spectra and development-regulated resistance of the transgenic plants carrying Xa3/Xa26 , Xa21 , or chimeric gene to different Xoo strains were analyzed in the same genetic background .
The results suggest that the gradually increased expression of Xa3/Xa26 and Xa21 plays an important role in the progressively enhanced Xoo resistance during rice development .
In addition , the LRR domains of XA3/XA26 and XA21 are important determinants of race-specific recognition during rice-Xoo interaction , but juxtamembrane regions of the two R proteins also appear to contribute to resistance specificity .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 6.00 |
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| | Author: Park CJ Bart R Chern M Canlas PE Bai W Ronald PC | | Journal: PLoS One Year: 2010 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub20174657 Accession (PMID): 20174657 | | Abstract: Recognition of pathogen-associated molecular patterns by pattern recognition receptors ( PRRs ) activates the innate immune response .
Although PRR-mediated signaling events are critical to the survival of plants and animals , secretion and localization of PRRs have not yet been clearly elucidated .
Here we report the in vivo interaction of the endoplasmic reticulum ( ER ) chaperone BiP3 with the rice XA21 PRR , which confers resistance to the Gram negative bacterium , Xanthomonas oryzae pv . oryzae ( Xoo ) .
We show that XA21 is glycosylated and is primarily localized to the ER and also to the plasma membrane ( PM ) .
In BiP3-overexpressing rice plants , XA21-mediated immunity is compromised , XA21 stability is significantly decreased , and XA21 proteolytic cleavage is inhibited .
BiP3 overexpression does not affect the general rice defense response , cell death or brassinolide-induced responses .
These results indicate that BiP3 regulates XA21 protein stability and processing and that this regulation is critical for resistance to Xoo .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
Score: 5.00 |
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| | Author: Xia ZH Li XB Chen CY Fan HK Jiang GH Zhu LH Zhai WX .
| | Journal: Sheng Wu Gong Cheng Xue Bao Year: 2006 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub16607944 Accession (PMID): 16607944 | | Abstract: The dominant gene Xa21 with broad-spectrum and high resistance to Xanthomonas oryzae pv . oryzae ( Xoo ) was transferred into C418 , an important restorer line of japonica hybrid rice in China using double right-border ( DRB ) T-DNA binary vector through Agrobacterium-mediated transformation .
17 transgenic lines were Xa21-positive with high resistance to the race P6 of Xoo through PCR analysis and resistance identification , among the total 27 independent primary transformants ( T0 ) obtained .
The subsequent analysis of the T1 progenies of these 17 T0 lines through PCR-assisted selection and resistance investigation showed that four Xa21 transgenic T0 lines could produce selectable marker-free ( SMF ) progenies .
The frequency of primary transformants producing SMF progenies was 15% .
In addition , PCR analysis also revealed these SMF progenies did not contain vector backbone sequence , and they were named as SMF and vector backbone sequence-free ( SMF-VBSF ) Xa21 transgenic plants .
The further molecular and phenotypic analysis of the T2 and T3 progenies testified the homozygous SMF-VBSF Xa21 transgenic plants were obtained with high resistance to Xoo .
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