Physiologic specialization of <i>Puccinia triticina</i>, the causal agent of wheat leaf rust, in Canada in 2015–2019

McCallum, Brent D.; Reimer, Elsa; Mcnabb, Winnie; Foster, Adam; Rosa, Sílvia Barcellos; Xue, Allen

doi:10.1080/07060661.2021.1888156

Cited by 29 publications

(36 citation statements)

References 27 publications

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“…The detection of the third 2BS gene, Lr23 , with the seedling test, but not in field trials, suggested that the ineffectiveness of the gene in the field was attributed to virulent races or a weak expressivity of the gene on adult plants. The frequency of virulence to Lr23 varied from 37.5 to 56.1% from 2015–2019 in Canada ( McCallum et al, 2021 ). Oelke and Kolmer (2005) reported one of Carberry’s parents, Alsen possesses Lr23 .…”

Section: Discussionmentioning

confidence: 99%

A Combination of Leaf Rust Resistance Genes, Including Lr34 and Lr46, Is the Key to the Durable Resistance of the Canadian Wheat Cultivar, Carberry

et al. 2022

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The hexaploid spring wheat cultivar, Carberry, was registered in Canada in 2009, and has since been grown over an extensive area on the Canadian Prairies. Carberry has maintained a very high level of leaf rust (Puccinia triticina Eriks.) resistance since its release. To understand the genetic basis of Carberry’s leaf rust resistance, Carberry was crossed with the susceptible cultivar, Thatcher, and a doubled haploid (DH) population of 297 lines was generated. The DH population was evaluated for leaf rust in seven field environments at the adult plant stage. Seedling and adult plant resistance (APR) to multiple virulence phenotypes of P. triticina was evaluated on the parents and the progeny population in controlled greenhouse studies. The population was genotyped with the wheat 90 K iSelect single nucleotide polymorphism (SNP) array, and quantitative trait loci (QTL) analysis was performed. The analysis using field leaf rust response indicated that Carberry contributed nine QTL located on chromosomes 1B, 2B (2 loci), 2D, 4A, 4B, 5A, 5B, and 7D. The QTL located on 1B, 2B, 5B, and 7D chromosomes were observed in two or more environments, whereas the remainder were detected in single environments. The resistance on 1B, detected in five environments, was attributed to Lr46 and on 7D, detected in seven environments to Lr34. The first 2B QTL corresponded with the adult plant gene, Lr13, while the second QTL corresponded with Lr16. The seedling analysis showed that Carberry carries Lr2a, Lr16, and Lr23. Five epistatic effects were identified in the population, with synergistic interactions being observed for Lr34 with Lr46, Lr16, and Lr2a. The durable rust resistance of Carberry is attributed to Lr34 and Lr46 in combination with these other resistance genes, because the resistance has remained effective even though the P. triticina population has evolved virulent to Lr2a, Lr13, Lr16, and Lr23.

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Section: Discussionmentioning

confidence: 99%

A Combination of Leaf Rust Resistance Genes, Including Lr34 and Lr46, Is the Key to the Durable Resistance of the Canadian Wheat Cultivar, Carberry

et al. 2022

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“…A. tauschii is the D genome progenitor of wheat and is known to be a good resource of resistance (R) genes. Among the Lr genes derived from the A. tauschii including, Lr21 , Lr22a , Lr32 , Lr41 and Lr42 , Lr22a is the only one that does not confer resistance at the seedling stage and also has no reported virulence (Cox et al, 1994; Dyck & Kerber, 1970; Hiebert et al, 2007; Kerber, 1987; McCallum et al, 2021; Rowland & Kerber, 1974). Lr22a was first reported by Rowland and Kerber (1974) and later mapped to chromosome arm 2DS with DNA markers by Hiebert et al (2007).…”

Section: Introductionmentioning

confidence: 99%

“…Since its initial deployment in Canada in 1991, virulence to Lr22a has not been detected to date. Tests for virulence to Lr22a are done annually by inoculating a representative isolate from each of the unique virulence phenotypes of P. triticina found in Canada each year, including in a recent analysis from 2015 to 2019 (McCallum et al, 2021). As highly effective resistance genes like Lr22a provide excellent control of leaf rust, it is important to introduce them into new wheat cultivars and preferably in gene combinations where Lr genes can mutually protect each other from evolution of virulence.…”

Section: Introductionmentioning

confidence: 99%

Development of single nucleotide polymorphism‐based functional molecular markers from the Lr22a gene sequence in wheat (Triticum aestivum)

2022

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The adult‐plant leaf rust resistant gene Lr22a confers broadly effective resistance against the fungal pathogen Puccinia triticina Eriks. (Pt) in wheat that has not been extensively utilized in wheat cultivars. The objective of this study was to develop robust functional molecular markers using the Lr22a gene sequence to facilitate integration of Lr22a in breeding programmes. The Lr22a coding sequence was used to identify isolated SNPs and four kompetitive allele specific polymerase chain reaction (PCR) (KASP) markers were developed. For marker testing, a F2:3 population was developed by crossing a near‐isogenic line RL4495 (Lr22a carrier) with Thatcher and phenotyped with Pt race TDBJ and genotyped with a 90K iSelect SNP array, four KASP markers and two SSR markers. A linkage map of chromosome arm 2DS that included Lr22a was constructed. The KASP markers co‐segregated with Lr22a and were validated for cross‐applicability on a panel of wheat lines. KASP markers Kwh636, Kwh637 and Kwh638 reliably detected the presence or absence of Lr22a. The markers developed in this study will facilitate Lr22a selection in breeding programmes.

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“…One of the few widely effective genes conferring resistance to leaf rust; Lr19, was transferred from the wild relative Thinopyrum ponticum, a diploid genus belonging to the poaceae family, into wheat where it is located on the long arm of the wheat chromosome 7D ( Sarma and Knott, 1966). This gene produces a hypersensitive response (Plotnikova, 2008) and rust surveys have shown its effectiveness over time and space (McCallum et al, 2021). Though Lr19 was originated from Th.…”

Section: Introductionmentioning

confidence: 99%

Molecular analyses in wheat and Aegilops tauschii reveals a new orthologue of the leaf rust resistance gene Lr19 on 7DL chromosome of Ae. tauschii

Pourkhorshid

Dadkhodaie

Shamloo‐Dashtpagerdi³

2021

Preprint

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Leaf rust is one of the most devastating wheat diseases worldwide, to which many resistance genes have been ‎successfully introgressed ‎from wheat wild relatives. Though the Thinopyrum ‎ponticum-derived leaf rust resistance gene Lr19, is widely effective worldwide and previous studies ‎have shown its likely presence in Aegilops tauschii, no ‎thorough investigation has been conducted to confirm this. The present study aimed to ‎examine the presence of Lr19 in Ae. tauschii using a collection of molecular and bioinformatic analysis. Accordingly, the Thatcher line was used as susceptible, and a Thatcher+Lr19 (TcLr19) and Agatha were used as resistant lines. CDHLQ pathotyping coupled with DNA markers genotyping verified the presence of an Lr19 orthologue on Ae. tauschii 7DL (AtLr19). Sequencing of the GB marker products from Ae. tauschii and TcLr19 showed 99% homology in these fragments, confirming phenotyping and genotyping results. Both isolated segments were matched to a putative melatonin biosynthesis gene, namely O-methyltransferase-2 (OMT2) mapped to 7DL, with 100% identity. A hierarchical gene network was reconstructed using all identified putative genes within a genomic region containing 2.5 cM upstream and downstream of the OMT2 gene. Results indicated that several numbers of important biotic stress-responsive genes such as RPM1, RGA2, TRIUR3, BURP12, and myosin-11, were located downstream of melatonin as a master regulator molecule through the OMT2 node. To our knowledge, this is the first report of finding an orthologue for ‎Lr19 in Ae. tauschii, which provides insights into the possible regulatory route of LR19.

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Physiologic specialization of Puccinia triticina, the causal agent of wheat leaf rust, in Canada in 2015–2019

Cited by 29 publications

References 27 publications

A Combination of Leaf Rust Resistance Genes, Including Lr34 and Lr46, Is the Key to the Durable Resistance of the Canadian Wheat Cultivar, Carberry

A Combination of Leaf Rust Resistance Genes, Including Lr34 and Lr46, Is the Key to the Durable Resistance of the Canadian Wheat Cultivar, Carberry

Development of single nucleotide polymorphism‐based functional molecular markers from the Lr22a gene sequence in wheat (Triticum aestivum)

Molecular analyses in wheat and Aegilops tauschii reveals a new orthologue of the leaf rust resistance gene Lr19 on 7DL chromosome of Ae. tauschii

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