Location: Cereal Disease LabTitle: Adult plant leaf rust resistance QTL derived from wheat line CI13227 maps to chromosomes 2AL, 4BS, and 7AL
Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2022
Publication Date: 5/11/2022
Citation: Kolmer, J.A., Rouse, M.N. 2022. Adult plant leaf rust resistance QTL derived from wheat line CI13227 maps to chromosomes 2AL, 4BS, and 7AL. The Plant Genome. 15(3). Article e20215. https://doi.org/10.1002/tpg2.20215.
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. A winter wheat designated as CI13227 T has had good leaf rust resistance for many years. The objective of this research was to determine the number of genes in CI13227 that give leaf rust resistance and also to determine on which chromosome in wheat the resistance genes were located on. CI13227 was determine to have three genes for resistance. The first gene was located on the short arm of chromosome 2A. The second gene was located on the short arm of chromosome 4B, and the third gene was located on the long arm of chromosome 7A. When present together the three genes have given good resistance to leaf rust. DNA markers were developed that will help wheat breeders select for these genes in developing new wheat cultivars with improved and better leaf rust resistance.
Technical Abstract: The winter wheat line CI13227 (Triticum aestivum L.) has been characterized as having adult plant resistance to leaf rust caused by Puccinia triticina Eriks. CI13227 was crossed with the susceptible spring wheat 'Thatcher' (Tc) and a Tc*2/CI13227 F6 line with adult plant leaf rust resistance designated as 411A was derived. Line 411A was crossed with Tc to develop an F6 recombinant inbred line (RIL) population. The parents and the F6 lines were assessed for leaf rust severity at the flag leaf stage in five field plot tests from 2011-2015 and were genotyped for single nucleotide polymorphism (SNP) markers with the Illumina iSelect 90K wheat bead array. A total of 2384 SNPs segregated among the RILs. Markers that were completely linked were removed, which left 474 markers that covered 2605 centi-Morgans (cM) for construction of the linkage map. Quantitative trait loci (QTL) on chromosomes 2AL, 4BS, and 7AL were associated with significant reduction in leaf rust severity in the field plot tests. RILs that had combinations of two or three of the QTLs had significantly lower leaf rust severity than the susceptible parent Tc. Kompetitive allele specific polymerase chain reaction (KASP) markers were developed for the SNPs that were closely associated with the three QTLS to facilitate marker-based selection of the leaf rust resistance in breeding programs.