Genetics of stem rust resistance in the spring wheat cultivar Thatcher and the enhancement of stem rust resistance by Lr34

Vanegas, Carmen D. Gavin; Garvin, David F.; Kolmer, J. A.

doi:10.1007/s10681-007-9541-0

Cited by 30 publications

(25 citation statements)

References 19 publications

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“…However, transfer of Lr34 into Thatcher results in the expression of effective stem rust resistance possibly through interaction of Lr34 with unlinked Thatcher genes. There is good evidence that the ‘enhancement effect’ of Lr34 on stem rust resistance is race specific suggesting that the mode of action is different to the race non-specific response conferred by this gene against leaf rust and stripe rust [11,12,14]. This study has confirmed that Lr67 is also associated with enhanced stem rust resistance in Thatcher.…”

Section: Discussionsupporting

confidence: 62%

Lr67 and Lr34 rust resistance genes have much in common – they confer broad spectrum resistance to multiple pathogens in wheat

et al. 2013

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BackgroundAdult plant rust resistance genes Lr67 and Lr34 confer race non-specific resistance to multiple fungal pathogens of wheat. Induced, susceptible mutants were characterised for both genes.ResultsThree categories of Lr34 mutants were identified that were either partial susceptible, fully susceptible or hyper-susceptible to stripe rust and leaf rust. The likely impact of the mutational change on the predicted Lr34 protein correlated with differences in response to rust infection. Four independent Lr67 mutants were recovered that were susceptible to stripe rust, leaf rust and stem rust pathogens, including one possible hyper-susceptible Lr67 mutant.ConclusionsDetailed study of Lr34 mutants revealed that subtle changes in resistance response to multiple pathogens were correlated with mutational changes in the predicted protein. Recovery of independent Lr67 mutants indicates that as for Lr34, a single gene at the Lr67 locus is likely to confer resistance to multiple pathogens. The infection phenotypes of Lr67 mutants closely resembled that of Lr34 mutants.

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Section: Discussionsupporting

confidence: 62%

Lr67 and Lr34 rust resistance genes have much in common – they confer broad spectrum resistance to multiple pathogens in wheat

et al. 2013

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“…Previous reports showed that the combination of Lr34 with additional genes from ‘Thatcher’ can contribute to enhanced stem rust resistance under field conditions [ 12 , 26 ]. Here, we have quantified possible interactions by examining the effect of Lr34 on Sr12 at the seedling stage.…”

Section: Resultsmentioning

confidence: 99%

“…Other studies have also examined the interactions between Lr34 and Sr genes found in ‘Thatcher’. One study suggested that Sr16 and Sr12 may have contributed to resistance of adult plants in their ‘Thatcher’-derived population but focused on resistance associated with markers on chromosome arm 2BL [ 26 ]. In a follow-up study, a QTL was identified in ‘Thatcher’ on chromosome arm 2BL that was enhanced by Lr34 [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

“…In a similar study, a QTL was found on chromosome 3B which corresponded to the map position of Sr12 as determined by testing their population at the seedling stage with a race of Pgt that was avirulent to Sr12 [ 12 ]. The above studies used populations that segregated for Lr34 and suggested that Sr12 plays an important role in the APR of ‘Thatcher’ [ 12 , 26 ]. Sr12 was assigned to the short arm of chromosome 3B by telocentric mapping; however the authors state that it is possible that Sr12 could be near the centromere on the long arm [ 29 ].…”

Section: Introductionmentioning

confidence: 99%

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Major Gene for Field Stem Rust Resistance Co-Locates with Resistance Gene Sr12 in ‘Thatcher’ Wheat

et al. 2016

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Stem rust, caused by Puccinia graminis (Pgt), is a damaging disease of wheat that can be controlled by utilizing effective stem rust resistance genes. ‘Thatcher’ wheat carries complex resistance to stem rust that is enhanced in the presence of the resistance gene Lr34. The purpose of this study was to examine APR in ‘Thatcher’ and look for genetic interactions with Lr34. A RIL population was tested for stem rust resistance in field nurseries in Canada, USA, and Kenya. BSA was used to find SNP markers associated with reduced stem rust severity. A major QTL was identified on chromosome 3BL near the centromere in all environments. Seedling testing showed that Sr12 mapped to the same region as the QTL for APR. The SNP markers were physically mapped and the region carrying the resistance was searched for sequences with homology to members of the NB-LRR resistance gene family. SNP marker from one NB-LRR-like sequence, NB-LRR3 co-segregated with Sr12. Two additional populations, including one that lacked Lr34, were tested in field nurseries. NB-LRR3 mapped near the maximum LOD for reduction in stem rust severity in both populations. Lines from a population that segregated for Sr12 and Lr34 were tested for seedling Pgt biomass and infection type, as well as APR to field stem rust which showed an interaction between the genes. We concluded that Sr12, or a gene closely linked to Sr12, was responsible for ‘Thatcher’-derived APR in several environments and this resistance was enhanced in the presence of Lr34.

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“…Indeed, there are several cases of resistance genes that do not show the same phenotype in parental varieties as compared to their progenies. Understanding this phenomenon was required in order identify the suppressor of the Lr34 leaf rust resistance gene in wheat (Vanegas et al, 2008). In another case, the Lr13 leaf rust resistance gene is known to enhance resistance only in the presence of Lr17 (Kolmer, 1992).…”

Section: Genetical Genomics Offers New Horizons To Investigate Plant mentioning

confidence: 99%

Prospects for advancing defense to cereal rusts through genetical genomics

Ballini¹,

Lauter²,

Wise³

2013

Front. Plant Sci.

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Rusts are one of the most severe threats to cereal crops because new pathogen races emerge regularly, resulting in infestations that lead to large yield losses. In 1999, a new race of stem rust, Puccinia graminis f. sp. tritici (Pgt TTKSK or Ug99), was discovered in Uganda. Most of the wheat and barley cultivars grown currently worldwide are susceptible to this new race. Pgt TTKSK has already spread northward into Iran and will likely spread eastward throughout the Indian subcontinent in the near future. This scenario is not unique to stem rust; new races of leaf rust (Puccinia triticina) and stripe rust (Puccinia striiformis) have also emerged recently. One strategy for countering the persistent adaptability of these pathogens is to stack complete- and partial-resistance genes, which requires significant breeding efforts in order to reduce deleterious effects of linkage drag. These varied resistance combinations are typically more difficult for the pathogen to defeat, since they would be predicted to apply lower selection pressure. Genetical genomics or expression Quantitative Trait Locus (eQTL) analysis enables the identification of regulatory loci that control the expression of many to hundreds of genes. Integrated deployment of these technologies coupled with efficient phenotyping offers significant potential to elucidate the regulatory nodes in genetic networks that orchestrate host defense responses. The focus of this review will be to present advances in genetical genomic experimental designs and analysis, particularly as they apply to the prospects for discovering partial disease resistance alleles in cereals.

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Genetics of stem rust resistance in the spring wheat cultivar Thatcher and the enhancement of stem rust resistance by Lr34

Cited by 30 publications

References 19 publications

Lr67 and Lr34 rust resistance genes have much in common – they confer broad spectrum resistance to multiple pathogens in wheat

Lr67 and Lr34 rust resistance genes have much in common – they confer broad spectrum resistance to multiple pathogens in wheat

Major Gene for Field Stem Rust Resistance Co-Locates with Resistance Gene Sr12 in ‘Thatcher’ Wheat

Prospects for advancing defense to cereal rusts through genetical genomics

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