Allelic variation for the rust resistance gene Lr34/Yr18 in Canadian wheat cultivars

McCallum, Brent D.; Humphreys, D. G.; Somers, Daryl J.; Dakouri, Abdulsalam; Cloutier, Sylvie

doi:10.1007/s10681-011-0519-6

Cited by 39 publications

(31 citation statements)

References 28 publications

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“…Alleles of resistant (Lr34res-D) and susceptible (Lr34sus-D) cultivars are characterized by only three mutations ). Only five major Lr34 haplotypes, either representing mutated versions of Lr34res-D or variants of Lr34sus-D, were identified in the wheat gene pool (Dakouri et al 2010(Dakouri et al , 2014Lagudah et al 2009;McCallum et al 2012). A recent study of a collection of 252 accessions of the D-genome progenitor of bread wheat, Aegilops tauschii, revealed very low nucleotide variation in Lr34 (π = 0.0011; Krattinger et al 2013), similar to the results presented here for Yr36.…”

Section: Reduced Genetic Diversity At the Wks1 Locussupporting

confidence: 82%

“…The characterization of nucleotide diversity of the leaf rust QR gene Lr34 revealed relatively lowsequence diversity. In the wheat gene pool, two predominant Lr34 alleles (Lr34res-D and Lr34sus-D) were found that differ by only two critical codons in exon 11 and exon 12 (Dakouri et al 2010;Krattinger et al 2009Krattinger et al , 2011Lagudah et al 2009;McCallum et al 2012). …”

Section: Introductionmentioning

confidence: 99%

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Distribution and haplotype diversity of WKS resistance genes in wild emmer wheat natural populations

et al. 2016

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paralogue WKS2 are present only in the southern distribution range of wild emmer in the Fertile Crescent, supporting the idea that wheat domestication occurred in the northern populations. An analysis of full-length WKS1 sequence from 54 accessions identified 15 different haplotypes and very low-nucleotide diversity (π = 0.00019). The high level of WKS1 sequence conservation among wild emmer populations is in contrast to the high level of diversity previously observed in NB-LRR genes (e.g., Lr10 and Pm3). This phenomenon may reflect the different resistance mechanisms and different evolutionary pathways that shaped these genes, and may shed light on the evolution of genes that confer partial resistance to stripe rust. Only five WKS1 coding sequence haplotypes were revealed among all tested accessions, encoding four different putative WKS1 proteins (designated P0, P1, P2, and P3). Infection tests showed that P0, P1, and P3 haplotypes display a resistance response, while P2 displayed a susceptible response. These results show that the WKS1 proteins (P0, P1, and P3) can be useful to improve wheat resistance to stripe rust.

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Section: Reduced Genetic Diversity At the Wks1 Locussupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Distribution and haplotype diversity of WKS resistance genes in wild emmer wheat natural populations

et al. 2016

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“…Breeding for resistance to leaf rust started in the late 1930s, when the susceptibility of ‘Thatcher’, which was grown extensively in the western Prairie Provinces from 1939 to 1960, resulted in severe yield and economic losses (McCallum and DePauw , McCallum et al. ). Since then, many resistance genes have been deployed.…”

Section: Biotic Stressesmentioning

confidence: 99%

Application of molecular markers to wheat breeding in Canada

et al. 2013

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Marker-assisted breeding provides an opportunity for wheat breeders to introgress/pyramid genes of interest into breeding lines and to identify genes and/or quantitative trait loci in germplasm to be used as parents. Molecular markers were deployed to assist selection for disease resistance, agronomic and quality traits in several wheat cultivars released for commercial cultivation in Canada. Marker-assisted breeding is routinely used in most wheat breeding programmes for rust resistance (leaf, stem and stripe rust), orange wheat blossom midge resistance, high grain protein concentration, Fusarium head blight and common bunt resistance. Markers are being used selectively within breeding programmes to target traits that relate to market class or regional adaptation. For example, marker-assisted breeding for low lipoxygenase activity and low grain cadmium is being performed in durum breeding programmes and for enhancing stem solidness in programmes targeting resistance to the wheat stem sawfly. Markers are also being utilized for ergot resistance in durum wheat. Increased gluten strength is being selected with a marker for the overexpression of the Bx7 high-molecular-weight glutenin subunit. Marker-assisted breeding is also being used to pyramid resistance genes against a group of stem rust races related to TTKS (Ug99), a disease that poses a serious threat to global wheat production. Development of tightly linked diagnostic markers and high-throughput genotyping with SNP markers will result in more effective molecular wheat breeding in the near future and will open the door to genomic selection.

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“…The tyrosine residue at position 634 of LR34sus-D is highly conserved among different ABCG proteins in various plant species (Krattinger et al 2011). Several additional Lr34 alleles have been identified at lower frequencies in the wheat genepool (Dakouri et al 2010;Lagudah et al 2009;McCallum et al 2012). However, none of these were associated with disease resistance and they either represent In this study we examined Lr34 homoeologs and orthologs in a set of wheat, rice and sorghum genotypes.…”

Section: Introductionmentioning

confidence: 99%

Recent emergence of the wheat Lr34 multi-pathogen resistance: insights from haplotype analysis in wheat, rice, sorghum and Aegilops tauschii

Krattinger

Jordan

Mace³

et al. 2012

Theor Appl Genet

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Spontaneous sequence changes and the selection of beneficial mutations are driving forces of gene diversification and key factors of evolution. In highly dynamic co-evolutionary processes such as plant-pathogen interactions, the plant's ability to rapidly adapt to newly emerging pathogens is paramount. The hexaploid wheat gene Lr34, which encodes an ATP-binding cassette (ABC) transporter, confers durable field resistance against four fungal diseases. Despite its extensive use in breeding and agriculture, no increase in virulence towards Lr34 has been described over the last century. The wheat genepool contains two predominant Lr34 alleles of which only one confers disease resistance. The two alleles, located on chromosome 7DS, differ by only two exon-polymorphisms. Putatively functional homoeologs and orthologs of Lr34 are found on the B-genome of wheat and in rice and sorghum, but not in maize, barley and Brachypodium. In this study we present a detailed haplotype analysis of homoeologous and orthologous Lr34 genes in genetically and geographically diverse selections of wheat, rice and sorghum accessions. We found that the resistant Lr34 haplotype is unique to the wheat D-genome and is not found in the B-genome of wheat or in rice and sorghum. Furthermore, we only found the susceptible Lr34 allele in a set of 252 Ae. tauschii genotypes, the progenitor of the wheat D-genome. These data provide compelling evidence that the Lr34 multi-pathogen resistance is the result of recent gene diversification occurring after the formation of hexaploid wheat about 8,000 years ago. AbstractSpontaneous sequence changes and the selection of beneficial mutations are driving forces of gene diversification and key factors of evolution. In highly dynamic coevolutionary processes such as plant-pathogen interactions, the plant's ability to rapidly adapt to newly emerging pathogens is paramount. The hexaploid wheat gene Lr34, which encodes an ATP-binding cassette (ABC) transporter, confers durable field resistance against four fungal diseases. Despite its extensive use in breeding and agriculture, no increase in virulence towards Lr34 has been described over the last century. The wheat genepool contains two predominant Lr34 alleles of which only one confers disease resistance. The two alleles, located on chromosome 7DS, differ by only two exon polymorphisms. Putatively functional homoeologs and orthologs of Lr34 are found on the B-genome of wheat and in rice and sorghum, but not in maize, barley and Brachypodium. In this study we present a detailed haplotype analysis of homoeologous and orthologous Lr34 genes in genetically and geographically diverse selections of wheat, rice and sorghum accessions. We found that the resistant Lr34 haplotype is unique to the wheat D-genome and is not found in the B-genome of wheat or in rice and sorghum. Furthermore, we only found the susceptible Lr34 allele in a set of 252 Ae. tauschii genotypes, the progenitor of the wheat D-genome. These data provide compelling evidence that the Lr34 mult...

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Allelic variation for the rust resistance gene Lr34/Yr18 in Canadian wheat cultivars

Abstract: The wheat (Triticum aestivum L.

Cited by 39 publications

References 28 publications

Distribution and haplotype diversity of WKS resistance genes in wild emmer wheat natural populations

Distribution and haplotype diversity of WKS resistance genes in wild emmer wheat natural populations

Application of molecular markers to wheat breeding in Canada

Recent emergence of the wheat Lr34 multi-pathogen resistance: insights from haplotype analysis in wheat, rice, sorghum and Aegilops tauschii

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