Gene-specific markers for the wheat gene Lr34/Yr18/Pm38 which confers resistance to multiple fungal pathogens
- 2.3k Downloads
The locus Lr34/Yr18/Pm38 confers partial and durable resistance against the devastating fungal pathogens leaf rust, stripe rust, and powdery mildew. In previous studies, this broad-spectrum resistance was shown to be controlled by a single gene which encodes a putative ATP-binding cassette transporter. Alleles of resistant and susceptible cultivars differed by only three sequence polymorphisms and the same resistance haplotype was found in the three independent breeding lineages of Lr34/Yr18/Pm38. Hence, we used these conserved sequence polymorphisms as templates to develop diagnostic molecular markers that will assist selection for durable multi-pathogen resistance in breeding programs. Five allele-specific markers (cssfr1–cssfr5) were developed based on a 3 bp deletion in exon 11 of the Lr34-gene, and one marker (cssfr6) was derived from a single nucleotide polymorphism in exon 12. Validation of reference genotypes, well characterized for the presence or absence of the Lr34/Yr18/Pm38 resistance locus, demonstrated perfect diagnostic values for the newly developed markers. By testing the new markers on a larger set of wheat cultivars, a third Lr34 haplotype, not described so far, was discovered in some European winter wheat and spelt material. Some cultivars with uncertain Lr34 status were re-assessed using the newly derived markers. Unambiguous identification of the Lr34 gene aided by the new markers has revealed that some wheat cultivars incorrectly postulated as having Lr34 may possess as yet uncharacterised loci for adult plant leaf and stripe rust resistance.
KeywordsWheat Cultivar Stripe Rust Adult Plant Resistance Stripe Rust Resistance Cleave Amplify Polymorphic Sequence Marker
We are indebted to the skilled technical support provided by Libby Viccars. This work was funded by the Grains Research and Development Corporation: grant #CSP00063 to CSIRO and project CIM13 to CIMMYT. Further funding was obtained from the Indo-Swiss Collaboration in Biotechnology to BK.
Conflict of interest statement
The authors declare that they have no conflict of interest.
- Borghi B (2001) Italian wheat pool. In: Bonjean AP, Angus WJ (eds) The world wheat book: a history of wheat breeding. Intercept, London, pp 289–309Google Scholar
- Dyck PL (1977) Genetics of leaf rust reaction in three introductions of common wheat. Can J Genet Cytol 19:711–716Google Scholar
- Dyck PL (1987) The association of a gene for leaf rust resistance with the chromosome 7D suppressor of stem rust resistance in common wheat. Genome 29:467–469Google Scholar
- Dyck PL (1991) Genetics of adult-plant leaf rust resistance in ‘Chinese Spring’ and ‘Sturdy’ wheats. Crop Sci 31:309–311Google Scholar
- Dyck PL, Samborski DJ (1979) Adult-plant leaf rust resistance in PI-250413, an introduction of common wheat. Can J Plant Sci 59:329–332Google Scholar
- Endo TR, Gill BS (1996) The deletion stocks of common wheat. J Hered 87:295–307Google Scholar
- Lagudah ES, Appels R, McNeil D (1991) The Nor-D3 locus of Triticum tauschii: natural variation and linkage to chromosome 5 markers. Genome 34:387–395Google Scholar
- McCallum BD, Somers DJ, Humphreys DG, Cloutier S (2008) Molecular marker analysis of Lr34 in Canada Western Red spring wheat cultivars. In: Appels R et al (eds) Proceedings of the 11th international wheat genetics symposium. Sydney University Press, SydneyGoogle Scholar
- McIntosh RA (1992) Close genetic linkage of genes conferring adult-plant resistance to leaf rust and stripe rust in wheat. Plant Pathol 41:523–527Google Scholar
- Singh RP (1993) Genetic association of gene Bdv1 for tolerance to barley yellow dwarf virus with genes Lr34 and Yr18 for adult plant resistance to rusts in bread wheat. Plant Dis 77:1103–1106Google Scholar
- Singh RP, Trethowan R (2007) Breeding spring bread wheat for irrigated and rainfed production systems of developing world. In: Kang M, Priyadarshan PM (eds) Breeding major food staples. Blackwell, Ames, pp 109–140Google Scholar
- Spielmeyer W, Singh RP, McFadden H, Wellings CR, Huerta-Espino J, Kong X, Appels R, Lagudah ES (2008) Fine scale genetic and physical mapping using interstitial deletion mutants of Lr34/Yr18: a disease resistance locus effective against multiple pathogens in wheat. Theor Appl Genet 116:481–490PubMedCrossRefGoogle Scholar