Genome-Wide Mapping of Quantitative Trait Loci Conferring All-Stage and High-Temperature Adult-Plant Resistance to Stripe Rust in Spring Wheat Landrace PI 181410

Abstract

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat in the world. Genetic resistance is the best strategy for control of the disease. Spring wheat landrace PI 181410 has shown high level resistance to stripe rust. The present study characterized the landrace to have both race-specific all-stage resistance and nonrace-specific high-temperature adult-plant (HTAP) resistance. To map quantitative trait loci (QTL) for the resistance in PI 181410, it was crossed with Avocet S (AvS), from which a recombinant inbred line population was developed. The F₅-F₈ populations were consecutively phenotyped for stripe rust response in multiple field environments under natural Pst infection, and the F₇ population was phenotyped in seedlings at low temperature and in adult-plant stage with selected Pst races in the greenhouse. The F₇ population was genotyped using the 90K wheat SNP chip. Three QTL, QYrPI181410.wgp-4AS, QYrPI181410.wgp-4BL, and QYrPI181410.wgp-5BL.1, from PI 181410 for all-stage resistance, were mapped on chromosome arms 4AS, 4BL, and 5BL, respectively. Four QTL, QYrPI181410.wgp-1BL, QYrPI181410.wgp-4BL, QYrPI181410.wgp-5AS, and QYrPI181410.wgp-5BL.2, were identified from PI 181410 for HTAP resistance and mapped to 1BL, 4BL, 5AS, and 5BL, respectively. Two QTL with minor effects on stripe rust response were identified from AvS and mapped to 2BS and 2BL. Four of the QTL from PI 181410 and one from AvS were potentially new. As the 4BL QTL was most effective and likely a new gene for stripe rust resistance, three kompetitive allele specific PCR (KASP) markers were developed for incorporating this gene into new wheat cultivars.

Keywords: Puccinia striiformis; QTL mapping; Triticum aestivum; disease resistance; stripe rust; wheat.

Figure 1

The distribution of infection types (ITs) among F₇ recombinant inbred lines (RILs) derived from the cross AvS × PI 181410 tested in greenhouse using races (A) PSTv-4 and (B) PSTv-14 of Puccinia striiformis f. sp. tritici.

Figure 2

The distribution of relative area under the disease progress curve (rAUDPC) among recombinant inbred lines (RILs) derived from the cross AvS × PI 181410 in the field tests in Pullman and Mount Vernon, WA in 2015, 2016, and/or 2017.

Figure 3

Genetic maps for the eight stripe rust resistance QTL identified in PI 181410 and AvS in this study. The solid bars on the left of each genetic map indicate the QTL position and interval.

Figure 4

The LOD curves of QYrPI181410.wgp-4BL detected on chromosome 4B using 12 sets of data collected from the field tests across all environments including six sets of infection type (IT) data, four sets of relative area under the disease progress curve (rAUDPC) data, and two sets of disease severity (SE) data. The horizontal dotted line indicates the LOD threshold at 3.0.

Figure 5

Comparison of mean infection type values of recombinant inbred lines (RILs) derived from cross AvS × PI 181410 containing different all-stage resistance QTL combination.

Figure 6

Comparison of mean infection type (A) and rAUDPC/severity (SE) (B) values of recombinant inbred lines (RILs) derived from cross AvS × PI 181410 containing different HTAP resistance QTL combination.