scholarly journals The barley leaf rust resistance gene Rph3 encodes a putative executor protein

2021 ◽  
Author(s):  
Hoan Dinh ◽  
Davinder Singh ◽  
Diana Cruz ◽  
Goetz Hensel ◽  
Martin Mascher ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Plant Disease Resistance ◽  
Wild Barley ◽  
Control Plant ◽  
Plant Diseases ◽  
Puccinia Hordei ◽  
Functional Markers ◽  
Leaf Rust Resistance Gene ◽  
Transcription Activator

Abstract Host resistance is considered the most effective means to control plant diseases; however, individually deployed resistance genes are often rapidly overcome by pathogen adaptation. Combining multiple effective resistance genes is the optimal approach to durable resistance, but the lack of functional markers for resistance genes has hampered implementation. Leaf rust, caused by Puccinia hordei, is an economically significant disease of barley, but only a few major Resistance genes to P. hordei (Rph) have been cloned. In this study, gene Rph3 was isolated by positional cloning and confirmed by mutational analysis and transgenic complementation. The Rph3 gene, which originated from wild barley and was first introgressed into cultivated Egyptian germplasm, encodes a unique transmembrane resistance protein that differs from all known plant disease resistance proteins at the amino acid sequence level. Genetic profiles of diverse accessions indicated limited genetic diversity in Rph3 in domesticated germplasm, and higher diversity in wild barley from the Eastern Mediterranean region. Expression profiling using P. hordei isolates with contrasting pathogenicity for the Rph3 host locus showed that the Rph3 gene was expressed only in interactions with Rph3-avirulent isolates, a phenomenon also observed for transcription activator-like effector-dependent genes known as executors conferring resistance to Xanthomonas spp. Like the known transmembrane executors such as Bs3 and Xa7 heterologous expression of Rph3 in N. benthamiana induced a cell death response. Given that Rph3 shares several features with executor genes, it seems likely that P. hordei contains effectors similar to the transcription activator-like effectors that target host executor genes. The isolation of Rph3 highlights convergent evolutionary processes in diverse plant-pathogen interaction systems, where similar defence mechanisms evolved independently in monocots and dicots and provide evidence for executor genes in the Triticeae tribe.

scholarly journals Chromosomal Location and Genetic Relationship of Leaf Rust Resistance Genes Rph9 and Rph12 in Barley

1998 ◽  
Vol 88 (1) ◽  
pp. 76-80 ◽  
Author(s):  
I. G. Borovkova ◽  
Y. Jin ◽  
B. J. Steffenson
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Chromosomal Location ◽  
Leaf Rust Resistance ◽  
Chromosome 7 ◽  
Puccinia Hordei ◽  
Leaf Rust Resistance Gene ◽  
Rust Resistance Genes ◽  
Leaf Rust Resistance Genes

Barley lines Hor 2596 and Triumph are the sources of leaf rust resistance genes Rph9 and Rph12, respectively. An allelism test was performed with F2 progeny of the cross Triumph/Hor 2596 inoculated with Puccinia hordei. No recombinants were found in a population of 3,858 progeny, indicating Rph9 and Rph12 are alleles. Molecular and morphological markers were used to identify the chromosomal location of these genes in the crosses Bowman/Hor 2596 and Triumph/I91-533-va. A linkage was detected between Rph9 and the flanking sequence-tagged site (STS) markers ABC155 and ABG3 on chromosome 7(5H) at a distance of 20.6 and 20.1 centimorgans (cM), respectively, and to the microsatellite marker dehydrin-9 (HVDHN9) at a distance of 10.2 cM in the Bowman/ Hor 2596 cross. Analysis of isozymes in bulks of the same population showed that Rph9 may be closely linked to the Est9 locus on chromosome 7(5H). The Rph12 locus was linked to the morphological trait locus va (controlling variegated leaf color) on chromosome 7(5H) at a distance of 22.6 cM in the Triumph/I91-533-va cross. Rph12 also was linked with STS marker ABC155 (24.4 cM) and RAPD marker OPA19 (1.5) (17.8 cM). These data indicate that Hor 2596 and Triumph carry a leaf rust resistance gene at the same locus on the long arm of chromosome 7(5H) of barley.

scholarly journals Identification and Molecular Characterization of Leaf Rust Resistance Gene Lr14a in Durum Wheat

Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 469-473 ◽  
Author(s):  
S. A. Herrera-Foessel ◽  
R. P. Singh ◽  
J. Huerta-Espino ◽  
H. M. William ◽  
V. Garcia ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Leaf Rust ◽  
Resistance Gene ◽  
Ssr Markers ◽  
Common Wheat ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Rust Resistance Gene ◽  
Leaf Rust Resistance Gene

Leaf rust, caused by Puccinia triticina, is an important disease of durum wheat (Triticum turgidum subsp. durum) and only a few designated resistance genes are known to occur in this crop. A dominant leaf rust resistance gene in the Chilean durum cv. Llareta INIA was mapped to chromosome arm 7BL through bulked segregant analysis using the amplified fragment length polymorphism (AFLP) technique, and by mapping three polymorphic markers in the common wheat (T. aestivum) International Triticeae Mapping Initiative population. Several simple sequence repeat (SSR) markers, including Xgwm344-7B and Xgwm146-7B, were associated with the leaf rust resistance gene. Resistance response and chromosomal position indicated that this gene is likely to be Lr14a. The SSR markers Xgwm344-7B and Xgwm146-7B and one AFLP marker also differentiated common wheat cv. Thatcher from the near-isogenic line with Lr14a, as well as durum ‘Altar C84’ from durum wheat with Lr14a. This is the first report of the presence of Lr14a in durum wheat, although the gene originally was transferred from emmer wheat ‘Yaroslav’ to common wheat. Lr14a is also present in CIMMYT-derived durum ‘Somateria’ and effective against Mexican and other P. triticina races of durum origin. Lr14a should be deployed in combination with other effective leaf rust resistance genes to prolong its effectiveness in durum wheat.

scholarly journals Identification and mapping of a leaf rust resistance gene in barley line Q21861

Genome ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 236-241 ◽  
Author(s):  
I. G. Borovkova ◽  
B. J. Steffenson ◽  
Y. Jin ◽  
A. Kilian ◽  
A. Kleinhofs ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Molecular Mapping ◽  
Bulked Segregant Analysis ◽  
Dominant Gene ◽  
Puccinia Hordei ◽  
Doubled Haploid Population ◽  
Leaf Rust Resistance Gene ◽  
Resistance Locus ◽  
Sequence Tagged Sites ◽  
Barley Line

Barley line Q21861 possesses an incompletely dominant gene (RphQ) for resistance to leaf rust caused by Puccinia hordei. To investigate the allelic and linkage relations between RphQ and other known Rph genes, F2 populations from crosses between Q21861 and donors of Rph1 to Rph14 (except for Rph8) were evaluated for leaf rust reaction at the seedling stage. Results indicate that RphQ is either allelic with or closely linked to the Rph2 locus. A doubled haploid population derived from a cross between Q21861 and SM89010 (a leaf rust susceptible line) was used for molecular mapping of the resistance locus. Bulked segregant analysis was used to identify markers linked to RphQ, using random amplified polymorphic DNAs (RAPDs), restriction fragment length polymorphisms (RFLPs), and sequence tagged sites (STSs). Of 600 decamer primers screened, amplified fragments generated by 9 primers were found to be linked to the RphQ locus; however, only 4 of them were within 10 cM of the target. The RphQ locus was mapped to the centromeric region of chromosome 7, with a linkage distance of 3.5 cM from the RFLP marker CDO749. Rrn2, an RFLP clone from the ribosomal RNA intergenic spacer region, was found to be very closely linked with RphQ, based on bulked segregant analysis. An STS marker, ITS1, derived from Rrn2, was also closely linked (1.6 cM) to RphQ.Key words: Hordeum vulgare, Puccinia hordei, allelism testing, linkage, molecular markers.

scholarly journals Development of a genetic linkage map for Sharon goatgrass (Aegilops sharonensis) and mapping of a leaf rust resistance gene

Genome ◽  
2013 ◽  
Vol 56 (7) ◽  
pp. 367-376 ◽  
Author(s):  
P.D. Olivera ◽  
A. Kilian ◽  
P. Wenzl ◽  
B.J. Steffenson
Keyword(s):  
Linkage Map ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Chromosomal Location ◽  
Dominant Gene ◽  
Leaf Rust Resistance Gene ◽  
Linkage Groups ◽  
Aegilops Sharonensis

Aegilops sharonensis (Sharon goatgrass), a diploid wheat relative, is known to be a rich source of disease resistance genes for wheat improvement. To facilitate the transfer of these genes into wheat, information on their chromosomal location is important. A genetic linkage map of Ae. sharonensis was constructed based on 179 F2 plants derived from a cross between accessions resistant (1644) and susceptible (1193) to wheat leaf rust. The linkage map was based on 389 markers (377 Diversity Arrays Technology (DArT) and 12 simple sequence repeat (SSR) loci) and was comprised of 10 linkage groups, ranging from 2.3 to 124.6 cM. The total genetic length of the map was 818.0 cM, with an average interval distance between markers of 3.63 cM. Based on the chromosomal location of 115 markers previously mapped in wheat, the four linkage groups of A, B, C, and E were assigned to Ae. sharonensis (Ssh) and homoeologous wheat chromosomes 6, 1, 3, and 2. The single dominant gene (designated LrAeSh1644) conferring resistance to leaf rust race THBJ in accession 1644 was positioned on linkage group A (chromosome 6Ssh) and was flanked by DArT markers wpt-9881 (at 1.9 cM distal from the gene) and wpt-6925 (4.5 cM proximal). This study clearly demonstrates the utility of DArT for genotyping uncharacterized species and tagging resistance genes where pertinent genomic information is lacking.

scholarly journals Validating molecular markers for barley leaf rust resistance genes Rph20 and Rph24

2020 ◽  
Author(s):  
PM Dracatos ◽  
RF Park ◽  
D Singh
Keyword(s):  
Molecular Markers ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Leaf Rust Resistance ◽  
Puccinia Hordei ◽  
Adult Plant ◽  
Barley Leaf Rust ◽  
Efficient Gene ◽  
Barley Leaf ◽  
Barley Germplasm

Improving resistance to barley leaf rust (caused by Puccinia hordei) is an important breeding objective in most barley growing regions worldwide. The development and subsequent utilisation of high-throughput PCR-based co-dominant molecular markers remains an effective approach to select genotypes with multiple effective resistance genes, permitting efficient gene deployment and stewardship. The genes Rph20 and Rph24 confer widely effective adult plant resistance (APR) to leaf rust, are common in European and Australian barley germplasm (often in combination), and act interactively to confer high levels of resistance (Dracatos et al. 2015; Zeims et al. 2017; Singh et al. 2018). Here we report on the development and validation of co-dominant insertion-deletion (indel) based PCR markers that are highly predictive for the Rph20 and Rph24 resistances.

scholarly journals Validating molecular markers for barley leaf rust resistance genes Rph20 and Rph24

Plant Disease ◽  
2020 ◽  
Author(s):  
P. M. Dracatos ◽  
Robert F Park ◽  
Davinder Singh
Keyword(s):  
Molecular Markers ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Leaf Rust Resistance ◽  
Puccinia Hordei ◽  
Adult Plant ◽  
Barley Leaf Rust ◽  
Efficient Gene ◽  
Barley Leaf ◽  
Barley Germplasm

Improving resistance to barley leaf rust (caused by Puccinia hordei) is an important breeding objective in most barley growing regions worldwide. The development and subsequent utilization of high-throughput polymerase chain reaction (PCR) based co-dominant molecular markers remains an effective approach to select genotypes with multiple effective resistance genes, permitting efficient gene deployment and stewardship. The genes Rph20 and Rph24, which confer widely effective adult plant resistance (APR) to leaf rust, are common in European and Australian barley germplasm (often in combination), and act interactively to confer high levels of resistance. Here we report on the development and validation of co-dominant insertion-deletion (indel) based PCR markers that are highly predictive for the resistance alleles Rph20.ai and Rph24.an (both referred to as Rph20 and Rph24).

A walk on the wild side: mining wild wheat and barley collections for rust resistance genes

2007 ◽  
Vol 58 (6) ◽  
pp. 532 ◽  
Author(s):  
Brian J. Steffenson ◽  
Pablo Olivera ◽  
Joy K. Roy ◽  
Yue Jin ◽  
Kevin P. Smith ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Stripe Rust ◽  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Wild Barley ◽  
Stem Rust Resistance ◽  
Dart Markers ◽  
Wide Range ◽  
Rust Resistance Genes

Leaf rust, stem rust, and stripe rust are among the most important diseases of wheat and barley worldwide and are best controlled using genetic resistance. To increase the diversity of rust resistance in wheat and barley, a project was initiated to identify and characterise rust resistance genes from the wild species of Aegilops sharonensis (Sharon goatgrass) and Hordeum vulgare ssp. spontaneum (wild barley), respectively. One hundred and two accessions of Sharon goatgrass from Israel and 318 Wild Barley Diversity Collection (WBDC) accessions from the Fertile Crescent, Central Asia, North Africa, and the Caucasus region were evaluated for resistance to leaf rust, stem rust, and/or stripe rust. Sharon goatgrass exhibited a wide range of infection types (ITs) in response to leaf rust, stem rust, and stripe rust. The percentage of resistant accessions in Sharon goatgrass was 58.8–78.4% for leaf rust, 11.8–69.6% for stem rust, and 46.1% for stripe rust, depending on the race used and the plant growth stage. Genetic studies with Sharon goatgrass revealed oligogenic resistance to leaf rust and stem rust. Wild barley also exhibited a wide range of ITs to leaf rust and stem rust; however, the overall frequency of resistance was lower than for Sharon goatgrass. The percentage of resistant accessions in wild barley was 25.8% for leaf rust and 5.7–20.1% for stem rust, depending on the race used. Resistance to the new virulent stem rust race TTKS (i.e. Ug99), present in eastern Africa, was found in both Sharon goatgrass (70% of accessions) and wild barley (25% of 20 accessions tested). Association mapping for stem rust resistance was applied in the WBDC using Diversity Arrays Technology (DArT) markers. Using the highly conservative P value threshold of 0.001, 14 and 15 significant marker associations were detected when the number of subpopulations (K value) was set for 10 and 8, respectively. These significant associations were in 9 and 8 unique chromosome bins, respectively. Two significant marker associations were detected for resistance to the wheat stem rust race MCCF in the same bin as the rpg4/Rpg5 complex on chromosome 7(5H). The presence of a major stem rust resistance gene in this bin on chromosome 7(5H) was validated in a bi-parental mapping population (WBDC accession Damon × cv. Harrington) constructed with DArT markers. The results from this study indicate that Sharon goatgrass and wild barley are rich sources of rust resistance genes for cultivated wheat and barley improvement, respectively, and that association mapping may be useful for positioning disease resistance genes in wild barley.

scholarly journals Occurrence and Pathogenicity of Puccinia hordei on Barley in South Africa

Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 713-717 ◽  
Author(s):  
B. D. van Niekerk ◽  
Z. A. Pretorius ◽  
W. H. P. Boshoff
Keyword(s):  
South Africa ◽  
Hordeum Vulgare ◽  
Leaf Rust ◽  
South African ◽  
Temperature Sensitivity ◽  
Resistance Genes ◽  
Puccinia Hordei ◽  
Breeding Lines ◽  
Pathogenic Variability ◽  
Important Disease

Although leaf rust, caused by Puccinia hordei, is considered an important disease of barley (Hordeum vulgare) and regularly reaches epidemic proportions, pathogenic variability has never been studied in South Africa. From 1994 to 1997, only one pathotype (SAPh 3231) was identified with virulence to resistance genes Rph1, Rph4, Rph5, Rph10, and Rph11. During 1998, a second pathotype (SAPh 7321) was identified, differing from pathotype SAPh 3231 only in virulence to Rph12. Pathotype SAPh 7321 increased rapidly in the area where it was first detected, resulting in localized epidemic outbreaks in 1999. The reactions of various South African cultivars and breeding lines toward these pathotypes were determined, and the presence of Rph12 was postulated for B93/4, Krona, Optic, Prisma, and SSG 532. Rph genes showed varying degrees of temperature sensitivity, with none of the known genes displaying major changes in their phenotypes except Rph8, which was less effective at higher temperatures. Eight accessions of two wild Hordeum spp. occurring abundantly in the barley growing regions were found to be either weak or nonhosts for P. hordei.

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