Characterisation of a new stripe rust resistance gene Yr47 and its genetic association with the leaf rust resistance gene Lr52

Abstract

Two Iranian common wheat landraces AUS28183 and AUS28187 from the Watkins collection showed high levels of seedling resistance against Australian pathotypes of leaf rust and stripe rust pathogens. Chi-squared analyses of rust response segregation among F(3) populations derived from crosses of AUS28183 and AUS28187 with a susceptible genotype AUS27229 revealed monogenic inheritance of leaf rust and stripe rust resistance. As both genotypes produced similar leaf rust and stripe rust infection types, they were assumed to carry the same genes. The genes were temporarily named as LrW1 and YrW1. Molecular mapping placed LrW1 and YrW1 in the short arm of chromosome 5B, about 10 and 15 cM proximal to the SSR marker gwm234, respectively, and the marker cfb309 mapped 8-12 cM proximal to YrW1. LrW1 mapped 3-6 cM distal to YrW1 in two F(3) populations. AUS28183 corresponded to the accession V336 of the Watkins collection which was the original source of Lr52. Based on the genomic location and accession records, LrW1 was concluded to be Lr52. Because no other seedling stripe rust resistance gene has previously been mapped in chromosome 5BS, YrW1 was permanently named as Yr47. A combination of flanking markers gwm234 and cfb309 with phenotypic assays could be used to ascertain the presence of Lr52 and Yr47 in segregating populations. This investigation characterised a valuable source of dual leaf rust and stripe rust resistance for deployment in new wheat cultivars. Transfer of Lr52 and Yr47 into current Australian wheat backgrounds is in progress.

Establishing the A. E. Watkins landrace cultivar collection as a resource for systematic gene discovery in bread wheat

“…The Watkins collection is proven to host interesting alleles, particularly for disease resistance (Dyck 1994; Bansal et al 2011; Thompson and Seymour 2011), which are mainly Mendelian genes and comparatively easy to identify. In order to facilitate the use of the collection, particularly for more complicated phenotypic screens, a core set of 119 lines was defined.…”

“…The Watkins collection has been successfully used to find new alleles or genes for leaf rust resistance (Dyck 1994), stripe rust resistance (Bansal et al 2011), and root-lesion nematode resistance (Thompson and Seymour 2011). However, all of these are Mendelian traits, and the determination of the chromosomal locations for such traits is comparatively easy.…”

Mapping Stripe Rust Resistance in a BrundageXCoda Winter Wheat Recombinant Inbred Line Population

“…The relationship between QYrco.wpg-5B and YrExp1 is unknown and warrants further investigation. The relationship of QYrbr.wpg-5B with Yr47 has not been determined, as this gene has not been tested with any U.S. races [78]. QYrbr.wpg-5B was derived from Coda and both Madsen and Tres have the same haplotype, indicating both parents may carry this QTL.…”

Mapping of a new stripe rust resistance locus Yr57 on chromosome 3BS of wheat

“…Yr47 (Bansal et al 2011) and Yr51 (Randhawa et al 2014) were previously identified from the Watkins collection, and Yr57 adds to the contribution of this collection in providing new genetic variation for stripe rust resistance. Six more genotypes are currently being investigated for potentially new sources of seedling resistance to stripe rust (Bariana and co-workers unpublished results).…”