scholarly journals Phylogeny and Genomic Organization of the TIR and Non-TIR NBS-LRR Resistance Gene Family in Medicago truncatul

2002 ◽  
Vol 15 (6) ◽  
pp. 529-539 ◽  
Author(s):  
Hongyan Zhu ◽  
Steven B. Cannon ◽  
Nevin D. Young ◽  
Douglas R. Cook

Sequences homologous to the nucleotide binding site (NBS) domain of NBS-leucine-rich repeat (LRR) resistance genes were retrieved from the model legume M. truncatula through several methods. Phylogenetic analysis classified these sequences into TIR (toll and interleukin-1 receptor) and non-TIR NBS subfamilies and further subclassified them into several well-defined clades within each subfamily. Comparison of M. truncatula NBS sequences with those from several closely related legumes, including members of the tribes Trifoleae, Viceae, and Phaseoleae, reveals that most clades contain sequences from multiple legume species. Moreover, sequences from species within the closely related Trifoleae and Viceae tribes (e.g., Medicago and Pisum spp.) tended to be cophyletic and distinct from sequences of Phaseoleae species (e.g., soybean and bean). These results suggest that the origin of major clades within the NBS-LRR family predate radiation of these Papilionoid legumes, while continued diversification of these sequences mirrors speciation within this legume subfamily. Detailed genetic and physical mapping of both TIR and non-TIR NBS sequences in M. truncatula reveals that most NBS sequences are organized into clusters, and few, if any, clusters contain both TIR and non-TIR sequences. Examples were found, however, of physical clusters that contain sequences from distinct phylogenetic clades within the TIR or non-TIR subfamilies. Comparative mapping reveals several blocks of resistance gene loci that are syntenic between M. truncatula and soybean and between M. truncatula and pea.

Genome ◽  
1997 ◽  
Vol 40 (5) ◽  
pp. 659-665 ◽  
Author(s):  
Evans S. Lagudah ◽  
Odile Moullet ◽  
Rudi Appels

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.


Genome ◽  
1998 ◽  
Vol 41 (6) ◽  
pp. 782-788 ◽  
Author(s):  
W Spielmeyer ◽  
M Robertson ◽  
N Collins ◽  
D Leister ◽  
P Schulze-Lefert ◽  
...  

In this study, resistance gene analogs (RGAs) which were isolated from monocot crop species (wheat, barley, maize and rice) and contained conserved sequence motifs found within the nucleotide binding site - leucine rich repeat (NBS-LRR) class of resistance genes, were used to assess their distribution in the wheat genome. The RGAs showed 30-70% amino acid identity to a previously isolated monocot NBS-LRR sequence from the Cre3 locus for cereal cyst nematode (CCN) resistance in wheat. We used the RGAs as probes to identify and map loci in wheat using recombinant inbred lines of an international Triticeae mapping family. RGA loci mapped across all seven homoeologous chromosome groups of wheat. This study demonstrated that the RGA mapping approach provides potential entry points toward identifying resistance gene candidates in wheat.Key words: wheat, disease resistance genes, nucleotide binding site, leucine rich repeat, resistance gene analogs.


Genome ◽  
2006 ◽  
Vol 49 (1) ◽  
pp. 54-63 ◽  
Author(s):  
M L Irigoyen ◽  
E Ferrer ◽  
Y Loarce

Sequences analogous to plant resistance genes of the NBS–LRR class were cloned from the genomic DNA of 11 Avena species with different genomes and levels of ploidy. Three pairs of degenerate primers were used, based on conserved DNA sequence motifs belonging to the NBS domain, and 33 sequences were identified. These were subdivided into 7 classes depending on nucleotide sequence identity. Despite the high level of degeneracy, the primers behaved in a highly selective way; the majority of sequences from the different species obtained with every primer combin ation showed strong identity and were considered homologous. For most species, only one sequence of each class was identified in each genome, suggesting that duplicated sequences are fairly divergent. The strong identity among specific NBS sequences precludes any conclusions being made on the evolution of these species. The genomic organization of the RGA sequences was explored using those of A. strigosa as probes in Southern blots involving digested DNA from 15 Avena species. The hybridization patterns showed wide diversity both among sequences within a species and among species for each sequence. However, the dendrogram generated using the RFLPs showed relationships among species to be in good agreement with those previously established using other molecular markers.Key words: resistance gene analog (RGA), disease resistance genes, diversity, Avena, oats.


2020 ◽  
Vol 16 ◽  
pp. 117693432091105
Author(s):  
Huawei Wei ◽  
Jia Liu ◽  
Qinwei Guo ◽  
Luzhao Pan ◽  
Songlin Chai ◽  
...  

NBS-LRR (nucleotide-binding site and leucine-rich repeat) is one of the largest resistance gene families in plants. The completion of the genome sequencing of wild tomato Solanum pimpinellifolium provided an opportunity to conduct a comprehensive analysis of the NBS-LRR gene superfamily at the genome-wide level. In this study, gene identification, chromosome mapping, and phylogenetic analysis of the NBS-LRR gene family were analyzed using the bioinformatics methods. The results revealed 245 NBS-LRRs in total, similar to that in the cultivated tomato. These genes are unevenly distributed on 12 chromosomes, and ~59.6% of them form gene clusters, most of which are tandem duplications. Phylogenetic analysis divided the NBS-LRRs into 2 subfamilies (CNL-coiled-coil NBS-LRR and TNL-TIR NBS-LRR), and the expansion of the CNL subfamily was more extensive than the TNL subfamily. Novel conserved structures were identified through conserved motif analysis between the CNL and TNL subfamilies. Compared with the NBS-LRR sequences from the model plant Arabidopsis thaliana, wide genetic variation occurred after the divergence of S. pimpinellifolium and A thaliana. Species-specific expansion was also found in the CNL subfamily in S. pimpinellifolium. The results of this study provide the basis for the deeper analysis of NBS-LRR resistance genes and contribute to mapping and isolation of candidate resistance genes in S. pimpinellifolium.


2011 ◽  
Vol 91 (6) ◽  
pp. 961-970 ◽  
Author(s):  
K. Cao ◽  
L. R. Wang ◽  
G. R. Zhu ◽  
CH. Fang ◽  
CH. W. Chen

Cao, K., Wang, L. R., Zhu, G. R., Fang, W. CH. and Chen, CH. W. 2011. Isolation, characterisation and phylogenetic analysis of resistance gene analogues in a wild species of peach ( Prunus kansuensis ). Can. J. Plant Sci. 91: 961–970. Conserved motifs, such as nucleotide binding site (NBS) and leucine-rich repeat (LRR) domains, have been found in resistance (R) genes cloned from plant species. These allow the study of plant defence mechanisms and isolating candidate genes in several species including peaches. Seventy-five resistance gene analogues (RGA) were identified using two different degenerative primer pairs in the Honggengansutao (Prunus kansuensis), a wild species of peach resistant to drought and nematodes. Through aligning their amino-acid sequences, P-loop and GLPL motifs were found in 48 RGAs with open-reading frames (ORF). These RGAs and 17 RGAs from Arabidopsis thaliana, Capsicum annuum and Solanum lycopersicum were grouped into two classes by phylogenetic analysis: toll and interleukin-1 receptor (TIR)- and non-TIR-NBS. Most Honggengansutao RGAs were TIR-NBS. A semiquantitative RT-PCR analysis revealed transcript-level variations of 22 RGAs in the young leaves, flowers, fruits and roots of the Honggengansutao, demonstrating their probable role in resistance against diseases attacking the organs. This is the first large-scale analysis of NBS-LRR RGAs in P. kansuensis, this technique has the potential for involvement in rootstock breeding. It will foster further R gene isolation and exploitation.


2004 ◽  
Vol 17 (2) ◽  
pp. 224-232 ◽  
Author(s):  
Donna Frost ◽  
Heather Way ◽  
Paul Howles ◽  
Joanne Luck ◽  
John Manners ◽  
...  

Tobacco was transformed with three different alleles (L2, L6, and L10) of the flax rust resistance gene L, a member of the toll interleukin-1 receptor, nucleotide-binding site, leucine-rich repeat (TIR-NBS-LRR) class of plant disease resistance genes. L6 transgenics had a stunted phenotype, expressed several defense response genes constitutively, and had increased resistance to the fungus Cercospora nicotianae and the oomycete Phytophthora parasitica pv. nicotianae. L2 and L10 transgenics, with one exception for L10, did not express these phenotypes, indicating that the activation of tobacco defense responses is L6 allele-specific. The phenotype of the exceptional L10 transgenic plant was associated with the presence of a truncated L10 gene resulting from an aberrant T-DNA integration. The truncated gene consisted of the promoter, the complete TIR region, and 39 codons of the NBS domain fused in-frame to a tobacco retrotransposon-like sequence. A similar truncated L10 gene, constructed in vitro, was transiently expressed in tobacco leaves and gave rise to a strong localized necrotic reaction. Together, these results suggest that defense signaling properties of resistance genes can be expressed in an allele-specific and pathogen-independent manner when transferred between plant genera.


2015 ◽  
Vol 105 (8) ◽  
pp. 1104-1113 ◽  
Author(s):  
Angela Feechan ◽  
Marianna Kocsis ◽  
Summaira Riaz ◽  
Wei Zhang ◽  
David M. Gadoury ◽  
...  

The Toll/interleukin-1 receptor nucleotide-binding site leucine-rich repeat gene, “resistance to Uncinula necator 1” (RUN1), from Vitis rotundifolia was recently identified and confirmed to confer resistance to the grapevine powdery mildew fungus Erysiphe necator (syn. U. necator) in transgenic V. vinifera cultivars. However, sporulating powdery mildew colonies and cleistothecia of the heterothallic pathogen have been found on introgression lines containing the RUN1 locus growing in New York (NY). Two E. necator isolates collected from RUN1 vines were designated NY1-131 and NY1-137 and were used in this study to inform a strategy for durable RUN1 deployment. In order to achieve this, fitness parameters of NY1-131 and NY1-137 were quantified relative to powdery mildew isolates collected from V. rotundifolia and V. vinifera on vines containing alleles of the powdery mildew resistance genes RUN1, RUN2, or REN2. The results clearly demonstrate the race specificity of RUN1, RUN2, and REN2 resistance alleles, all of which exhibit programmed cell death (PCD)-mediated resistance. The NY1 isolates investigated were found to have an intermediate virulence on RUN1 vines, although this may be allele specific, while the Musc4 isolate collected from V. rotundifolia was virulent on all RUN1 vines. Another powdery mildew resistance locus, RUN2, was previously mapped in different V. rotundifolia genotypes, and two alleles (RUN2.1 and RUN2.2) were identified. The RUN2.1 allele was found to provide PCD-mediated resistance to both an NY1 isolate and Musc4. Importantly, REN2 vines were resistant to the NY1 isolates and RUN1REN2 vines combining both genes displayed additional resistance. Based on these results, RUN1-mediated resistance in grapevine may be enhanced by pyramiding with RUN2.1 or REN2; however, naturally occurring isolates in North America display some virulence on vines with these resistance genes. The characterization of additional resistance sources is needed to identify resistance gene combinations that will further enhance durability. For the resistance gene combinations currently available, we recommend using complementary management strategies, including fungicide application, to reduce populations of virulent isolates.


Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 735-743 ◽  
Author(s):  
A Joyeux ◽  
M G Fortin ◽  
R Mayerhofer ◽  
A G Good

Genetic mapping of plants traditionally involves the analysis of large segregating populations. However, not all individuals in a population contribute equal amounts of genetic information. It is thus possible to achieve rough mapping using a subset of the most informative individuals in the population. We have designed a minimal Brassica napus mapping population of 23 doubled-haploid plants and have tested this method using this population in the mapping of disease resistance gene homologues in B. napus. Several groups have identified such homologues in soybean and potato by amplifying sequences corresponding to conserved nucleotide-binding sites from known resistance genes. However, the sequence conservation in the leucine-rich repeat domain that is present in most of the disease resistance genes isolated has not been exploited via the polymerase chain reaction (PCR). We present the genetic mapping of Brassica napus DNA sequences amplified with primers corresponding to both the nucleotide-binding site and the leucine rich-repeat domain of the Arabidopsis thaliana RPS2 gene. We also describe a method for the quick mapping of resistance gene homologues using the polymerase chain reaction.Key words: Brassica napus, disease resistance genes, minimal mapping population, RFLP markers.


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