Location: Cereal Crops ResearchTitle: Fine mapping of the chromosome 5B region carrying closely linked rust resistance genes Yr47 and Lr52 in wheat Author
|Qureshi, Naeela - University Of Sydney|
|Bariana, Harbans - University Of Sydney|
|Forrest, Kerrie - La Trobe University|
|Hayden, Matthew - La Trobe University|
|Keller, Beat - University Of Zurich|
|Wicker, Thomas - University Of Zurich|
|Salina, Elena - Russian Academy Of Sciences|
|Bansal, Urmil - University Of Sydney|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2016
Publication Date: 3/1/2017
Citation: Qureshi, N., Bariana, H., Forrest, K., Hayden, M., Keller, B., Wicker, T., Faris, J.D., Salina, E., Bansal, U. 2017. Fine mapping of the chromosome 5B region carrying closely linked rust resistance genes Yr47 and Lr52 in wheat. Theoretical and Applied Genetics. 130:495-504.
Interpretive Summary: Leaf rust and strip rust are serious diseases of wheat worldwide and have the capability to cause devastating yield losses. The pathogens that cause these diseases have the ability to mutate rapidly, which often results in currently deployed diseases resistance genes losing their effectiveness. Therefore, new rust resistance genes and tools to rapidly deploy them, such as molecular markers, are needed to continuously obtain rust-resistant wheat varieties. The genes known as Yr47 and Lr52 confer resistance to stripe and leaf rust, respectively, and both genes are located on the same wheat chromosome. Genomic and genetic analyses were conducted to determine the genetic distance between the genes and to develop new and useful molecular markers associated with the genes. The results indicated that Yr47 and Lr52 are located very near to each other, but they do not occupy the same locus. Several new molecular markers were developed and demonstrated to be useful to use in marker-assisted selection schemes to move these two effective resistance genes into adapted wheat cultivars.
Technical Abstract: The widely effective and linked rust resistance genes Yr47 and Lr52 were previously mapped in the short arm of chromosome 5B in two F3 populations (Aus28183/Aus27229 and Aus28187/Aus27229). The Aus28183/Aus27229 F3 population was advanced to generate an F6 recombinant inbred line (RIL) population to identify markers linked closely with Yr47 and Lr52. Diverse genomic resources including survey sequence scaffolds representing the orthologous region in Brachypodium distachyon, a physical map of chromosome 5BS, expressed sequence tags (ESTs) located in the 5BS6-0.81-1.00 deletion bin, and RGA contigs of chromosome arm 5BS were used to saturate the target region. Selective genotyping was also carried out using the iSelect 90K Infinium SNP assay. KASP markers were designed from the SNP sequences that exhibited linkage with Yr47 and Lr52. Polymorphic SSR, STS, gene-based, and SNP markers were genotyped on the entire RIL population. Yr47 and Lr52 were mapped 0.4 cM apart in the RIL population as opposed to a much higher recombination value reported by Bansal et al. (2011). The SSR marker sun180 co-segregated with Lr52 and mapped 0.4 cM distal to Yr47. In a high resolution mapping population of 600 genotypes, Yr47 and Lr52 mapped 0.2 cM apart and the marker sun180 was placed 0.4 cM distal to Lr52. The amplification of a different sun180 allele (195 bp) than that linked with Yr47 and Lr52 (200 bp) in 196 diverse wheat genotypes demonstrated its robustness in marker-assisted selection of these genes.