scholarly journals Mutational Analysis of the Arabidopsis RPS2 Disease Resistance Gene and the Corresponding Pseudomonas syringae avrRpt2 Avirulence Gene

2001 ◽  
Vol 14 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Michael J. Axtell ◽  
Timothy W. McNellis ◽  
Mary Beth Mudgett ◽  
Caroline S. Hsu ◽  
Brian J. Staskawicz
Keyword(s):  
Disease Resistance ◽  
Resistance Gene ◽  
Pseudomonas Syringae ◽  
Resistance Genes ◽  
Mutational Analysis ◽  
Defense Responses ◽  
Avirulence Gene ◽  
Disease Resistance Gene ◽  
In Planta ◽  
Hypersensitive Cell Death

Plants have evolved a large number of disease resistance genes that encode proteins containing conserved structural motifs that function to recognize pathogen signals and to initiate defense responses. The Arabidopsis RPS2 gene encodes a protein representative of the nucleotide-binding site-leucine-rich repeat (NBS-LRR) class of plant resistance proteins. RPS2 specifically recognizes Pseudomonas syringae pv. tomato strains expressing the avrRpt2 gene and initiates defense responses to bacteria carrying avrRpt2, including a hypersensitive cell death response (HR). We present an in planta mutagenesis experiment that resulted in the isolation of a series of rps2 and avrRpt2 alleles that disrupt the RPS2-avrRpt2 gene-for-gene interaction. Seven novel avrRpt2 alleles incapable of eliciting an RPS2-dependent HR all encode proteins with lesions in the C-terminal portion of AvrRpt2 previously shown to be sufficient for RPS2 recognition. Ten novel rps2 alleles were characterized with mutations in the NBS and the LRR. Several of these alleles code for point mutations in motifs that are conserved among NBS-LRR resistance genes, including the third LRR, which suggests the importance of these motifs for resistance gene function.

scholarly journals Identification of Three Putative Signal Transduction Genes Involved in R Gene-Specified Disease Resistance in Arabidopsis

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 401-412 ◽  
Author(s):  
Randall F Warren ◽  
Peter M Merritt ◽  
Eric Holub ◽  
Roger W Innes
Keyword(s):  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Resistance Genes ◽  
Virulent Strain ◽  
Disease Resistance Genes ◽  
Avirulence Gene ◽  
Detectable Effect ◽  
Disease Resistance Gene ◽  
Protein Functions ◽  
Signal Transduction Genes

Abstract The RPS5 disease resistance gene of Arabidopsis mediates recognition of Pseudomonas syringae strains that possess the avirulence gene avrPphB. By screening for loss of RPS5-specified resistance, we identified five pbs (avrPphB susceptible) mutants that represent three different genes. Mutations in PBS1 completely blocked RPS5-mediated resistance, but had little to no effect on resistance specified by other disease resistance genes, suggesting that PBS1 facilitates recognition of the avrPphB protein. The pbs2 mutation dramatically reduced resistance mediated by the RPS5 and RPM1 resistance genes, but had no detectable effect on resistance mediated by RPS4 and had an intermediate effect on RPS2-mediated resistance. The pbs2 mutation also had varying effects on resistance mediated by seven different RPP (recognition of Peronospora parasitica) genes. These data indicate that the PBS2 protein functions in a pathway that is important only to a subset of disease-resistance genes. The pbs3 mutation partially suppressed all four P. syringae-resistance genes (RPS5, RPM1, RPS2, and RPS4), and it had weak-to-intermediate effects on the RPP genes. In addition, the pbs3 mutant allowed higher bacterial growth in response to a virulent strain of P. syringae, indicating that the PBS3 gene product functions in a pathway involved in restricting the spread of both virulent and avirulent pathogens. The pbs mutations are recessive and have been mapped to chromosomes I (pbs2) and V (pbs1 and pbs3).

Functional characterization of the Arabidopsis disease resistance gene RPS4

2005 ◽  
Author(s):  
◽  
Xue-Cheng Zhang
Keyword(s):  
Disease Resistance ◽  
Alternative Splicing ◽  
Protein Stability ◽  
Resistance Gene ◽  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Alternative Transcript ◽  
Disease Resistance Gene ◽  
Dependent Manner ◽  
Multiple Transcripts

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The Arabidopsis disease resistance gene RPS4 activates defense responses to the bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000 expressing avrRps4 in a gene-for-gene specific manner. Like other plant TIRNBS-LRR resistance genes, RPS4 produces multiple transcripts via alternative splicing. Alternative RPS4 transcripts are predominantly generated by intron retention. First, the biological significance of these alternative transcripts in disease resistance was analyzed. It was shown that alternative RPS4 transcripts are required for complete function and that RPS4-mediated resistance requires the combined presence of multiple transcripts encoding both full-length and truncated open reading frames. Interestingly, the dominant alternative transcript is the only alternative transcript whose abundance relative to the regular transcript undergoes dramatic and dynamic changes during the resistance response. Furthermore, RPS4 expression is induced by AvrRps4 and an unrelated effector, HopPsyA, in an EDS1-dependent manner. These data suggest that rapid gene induction and changes in transcript ratios might be under coordinated regulation that are important to fine-tune RPS4-mediated resistance. Our previous data showed that removal of one intron abolished RPS4 function. However, no significant changes of transcript ratios in intron-deficient transgenic rps4-1 plants were observed compared to rps4-1 expressing a wild type genomic transgene, suggesting that the artificial removal of one intron has no effect on the splicing frequency of other introns. In consistent with our previous data, analyses on secondary RNA structures suggest that alternative RPS4 transcripts function at protein level. Of the three expected truncated RPS4 proteins, only one was detected and stable in vivo, indicating that RPS4 protein stability or activity is regulated. In summary, RPS4 function is regulated at multiple levels including gene expression, alternative splicing and protein stability or activity.

Organization, Expression and Evolution of a Disease Resistance Gene Cluster in Soybean

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1961-1977
Author(s):  
Michelle A Graham ◽  
Laura Fredrick Marek ◽  
Randy C Shoemaker
Keyword(s):  
Disease Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Developmental Stages ◽  
Gene Evolution ◽  
Pcr Amplification ◽  
Disease Resistance Genes ◽  
Disease Resistance Gene ◽  
R Genes ◽  
Specific Primers

Abstract PCR amplification was previously used to identify a cluster of resistance gene analogues (RGAs) on soybean linkage group J. Resistance to powdery mildew (Rmd-c), Phytophthora stem and root rot (Rps2), and an ineffective nodulation gene (Rj2) map within this cluster. BAC fingerprinting and RGA-specific primers were used to develop a contig of BAC clones spanning this region in cultivar “Williams 82” [rps2, Rmd (adult onset), rj2]. Two cDNAs with homology to the TIR/NBD/LRR family of R-genes have also been mapped to opposite ends of a BAC in the contig Gm_Isb001_091F11 (BAC 91F11). Sequence analyses of BAC 91F11 identified 16 different resistance-like gene (RLG) sequences with homology to the TIR/NBD/LRR family of disease resistance genes. Four of these RLGs represent two potentially novel classes of disease resistance genes: TIR/NBD domains fused inframe to a putative defense-related protein (NtPRp27-like) and TIR domains fused inframe to soybean calmodulin Ca2+-binding domains. RT-PCR analyses using gene-specific primers allowed us to monitor the expression of individual genes in different tissues and developmental stages. Three genes appeared to be constitutively expressed, while three were differentially expressed. Analyses of the R-genes within this BAC suggest that R-gene evolution in soybean is a complex and dynamic process.

Map-based cloning of a gene sequence encoding a nucleotide-binding domain and a leucine-rich region at the Cre3 nematode resistance locus of wheat

Genome ◽  
1997 ◽  
Vol 40 (5) ◽  
pp. 659-665 ◽  
Author(s):  
Evans S. Lagudah ◽  
Odile Moullet ◽  
Rudi Appels
Keyword(s):  
Disease Resistance ◽  
Gene Family ◽  
Binding Site ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Gene Sequence ◽  
Nucleotide Binding ◽  
Disease Resistance Gene ◽  
Leucine Rich Repeat ◽  
Rich Region

The Cre3 gene confers a high level of resistance to the root endoparasitic nematode Heterodera avenae in wheat. A DNA marker cosegregating with H. avenae resistance was used as an entry point for map-based cloning of a disease resistance gene family at the Cre3 locus. Two related gene sequences have been analysed at the Cre3 locus. One, identified as a cDNA clone, encodes a polypeptide with a nucleotide binding site (NBS) and a leucine-rich region; this member of the disease resistance gene family is expressed in roots. A second Cre3 gene sequence, cloned as genomic DNA, appears to be a pseudogene, with a frame shift caused by a deletion event. These two genes, related to members of the cytoplasmic NBS – leucine rich repeat class of plant disease resistance genes were physically mapped to the distal 0.06 fragment of the long arm of wheat chromosome 2D and cosegregated with nematode resistance.Key words: cereal cyst nematode, disease resistance genes, nucleotide-binding site, leucine-rich repeat.

scholarly journals The Isolation and Mapping of Disease Resistance Gene Analogs in Maize

1998 ◽  
Vol 11 (10) ◽  
pp. 968-978 ◽  
Author(s):  
N. C. Collins ◽  
C. A. Webb ◽  
S. Seah ◽  
J. G. Ellis ◽  
S. H. Hulbert ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Plant Disease Resistance ◽  
Amino Acid Identity ◽  
Disease Resistance Gene ◽  
Resistance Gene Analogs ◽  
Resistance Proteins ◽  
Genomic Regions ◽  
Leucine Rich Repeats

Many of the plant disease resistance genes that have been isolated encode proteins with a putative nucleotide binding site and leucine-rich repeats (NBS-LRR resistance genes). Oligonucleotide primers based on conserved motifs in and around the NBS of known NBS-LRR resistance proteins were used to amplify sequences from maize genomic DNA by polymerase chain reaction (PCR). Eleven classes of non-cross-hybridizing sequences were obtained that had predicted products with high levels of amino acid identity to NBS-LRR resistance proteins. These maize resistance gene analogs (RGAs) and one RGA clone obtained previously from wheat were used as probes to map 20 restriction fragment length polymorphism (RFLP) loci in maize. Some RFLPs were shown to map to genomic regions containing virus and fungus resistance genes. Perfect co-segregation was observed between RGA loci and the rust resistance loci rp1 and rp3. The RGA probe associated with rp1 also detected deletion events in several rp1 mutants. These data strongly suggest that some of the RGA clones may hybridize to resistance genes.

scholarly journals Small RNAs and Gene Network in a Durable Disease Resistance Gene—Mediated Defense Responses in Rice

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0137360 ◽  
Author(s):  
Hanming Hong ◽  
Yanyan Liu ◽  
Haitao Zhang ◽  
Jinghua Xiao ◽  
Xianghua Li ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Resistance Gene ◽  
Small Rnas ◽  
Gene Network ◽  
Defense Responses ◽  
Disease Resistance Gene ◽  
Durable Disease Resistance
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