Adult plant leaf rust resistance in AC Taber wheat maps to chromosomes 2BS and 3BS

Authors: Kolmer, James; TURNER, MARILYN - University Of Minnesota; Rouse, Matthew; ANDERSON, JAMES - University Of Minnesota

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2020
Publication Date: 2/19/2021
Citation: Kolmer, J.A., Turner, M.K., Rouse, M.N., Anderson, J.A. 2021. Adult plant leaf rust resistance in AC Taber wheat maps to chromosomes 2BS and 3BS. Phytopathology. 111(2):380-385. https://doi.org/10.1094/PHYTO-03-20-0074-R.
DOI: https://doi.org/10.1094/PHYTO-03-20-0074-R

Interpretive Summary: Wheat is attacked by the leaf rust fungus called Puccinia triticina. Many of the leaf rust resistance genes in wheat cultivars no longer give good resistance to leaf rust, since biotypes of the rust fungus have the ability to overcome the resistance genes. The Canadian wheat cultivar AC Taber has had very good leaf rust resistance for many years. The objective of this research was to determine the number of genes in AC Taber that gave leaf rust resistance and also to determine on which chromosome in wheat the resistance genes were located on. AC Taber was determine to have two genes for resistance. The first gene was located on the short arm of chromosome 2B and was determined to be the gene Lr13. The second gene was located on the short arm of chromosome 3B and is likely the gene Lr74. Both of these genes give good resistance to leaf rust. This information on AC Taber and the location of the leaf rust resistance genes can be used by wheat breeders and pathologists to improve leaf rust resistance in wheat.

Technical Abstract: AC Taber is a hard red spring wheat cultivar that has had long lasting resistance to the leaf rust fungus Puccinia triticina. The objective of this study was to determine the chromosome location of the leaf rust resistance genes in AC Taber. The leaf rust susceptible cultivar 'Thatcher' was crossed with AC Taber to develop an F6 recombinant inbred line (RIL) population. The RILs and parents were evaluated for segregation of leaf rust resistance in five field plot tests and as seedlings to two different races of P. triticina. A genetic map of the RIL population was developed using 90,000 single-nucleotide polymorphism (SNP) markers with the Illumina Infinium iSelect 90K wheat bead array. Quantitative trait loci (QTL) with significant effects for lower leaf rust severity in the field plot tests were found on chromosomes 2BS and 3BS. The same QTLs also had significant effects for lower infection type in seedlings to leaf rust race BBBDB. The gene on 2BS is the adult plant resistance gene Lr13, and the gene on 3BS mapped to the same region as the adult plant resistance gene Lr74 and other QTLs for leaf rust resistance. An additional QTL for seedling resistance on chromosome 5BL was detected with race TCTDB. Kompetitive allele specific polymerase chain reaction (KASP) assay markers linked to the 2BS and 3BS regions were developed and should be useful for marker based selection of these genes.