Quantitative Trait Loci for High-Temperature Adult-Plant and Slow-Rusting Resistance to Puccinia striiformis f. sp. tritici in Wheat Cultivars

Abstract

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most damaging diseases of wheat (Triticum aestivum) globally. High-temperature adult-plant resistance (HTAPR) and slow-rusting have great potential for sustainable management of the disease. The wheat cultivars Luke and Aquileja have been previously reported to possess HTAPR and slow-rusting to stripe rust, respectively. Aquileja displayed less number of stripes per unit leaf area than Luke, while Luke showed lower infection type than Aquileja at adult-plant stages of growth under high-temperature conditions. The objectives of this study were to confirm the resistances and to map the resistance genes in Luke and Aquileja. Luke was crossed with Aquileja, and 326 of the F(2) plants were genotyped using 282 microsatellite primer pairs. These F(2) plants and their derived F(3) families were evaluated for resistance to stripe rust by inoculation in the fields and greenhouses of high- and low-temperatures. Infection type was recorded for both seedlings and adult plants, and stripe number was recorded for adult plants only. Two quantitative trait loci (QTL) were identified, on the short arm of chromosome 2B, to be significantly associated with infection type at adult-plant stages in the fields and in the high-temperature greenhouse. The locus distal to centromere, referred to as QYrlu.cau-2BS1, and the locus proximal to centromere, referred to as QYrlu.cau-2BS2, were separated by a genetic distance of about 23 cM. QYrlu.cau-2BS1 was flanked by the microsatellite markers Xwmc154 and Xgwm148, and QYrlu.cau-2BS2 was flanked by Xgwm148 and Xabrc167. QYrlu.cau-2BS1 and QYrlu.cau-2BS2 explained up to 36.6 and 41.5% of the phenotypic variation of infection type, respectively, and up to 78.1% collectively. No significant interaction between the two loci was detected. Another QTL, referred to as QYraq.cau-2BL, was detected on the long arm of chromosome 2B to be significantly associated with stripe number. QYraq.cau-2BL was flanked by the microsatellite markers Xwmc175 and Xwmc332, and it explained up to 61.5% of the phenotypic variation of stripe number. It is possible that these three QTL are previously unmapped loci for resistance to stripe rust.

Saturation Mapping of a Major Effect QTL for Stripe Rust Resistance on Wheat Chromosome 2B in Cultivar Napo 63 Using SNP Genotyping Arrays

“…Several stripe rust QTLs with major APR effects for on chromosome 2BS have been reported (Rosewarne et al, 2013). For example, QYrlu.cau-2BS1 and QYrlu.cau-2BS2 in Luke, QYrid.ui-2B.1 and QYrid.ui-2B.2 in IDO444, QYr.sgi-2B.1 in Kariega, QYrlo.wpg-2BS in Louise, QYr-2B in Opata 85 and QYr.inra-2B.1 in Camp Remy conferring large effects were located in a similar region (Boukhatem et al, 2002; Mallard et al, 2005; Guo et al, 2008; Carter et al, 2009; Prins et al, 2011; Chen et al, 2012). Based on the integrative genetic map (Maccaferri et al, 2015b) all of the above major QTLs were within the interval 19.9–50.2 cM, within which we placed Qyrnap.nwafu-2BS between 40.02 and 43.44 cM.…”

Review Article: High-Temperature Adult-Plant Resistance, Key for Sustainable Control of Stripe Rust

“…Nugaines and Gaines were major cultivars in the PNW from 1960s until 1981 [6] as cultivars with higher yielding and better HTAP resistance became predominant. Nugaines and Luke also showed HTAP resistance in China [20,21]. Since late 1970s, more and more wheat cultivars with high levels of HTAP resistance have been developed and (Figure 2).…”

“…A major QTL controlled HTAP resistance was reported in Alpowa (Yr39) [47], Compair and the AvSYr9NIL line [48], Louise [30] and PI 183527 (Yr52) [58] wheat genotypes and Bancroft barley [49]. Two-QTL controlled HTAP resistance was reported in wheat cultivars Stephens [53], Luke [21], PI 610750 (including Yr48), UC1110 [59] and Rio Blanco [56]. Three-QTL controlled HTAP resistance was reported in wheat cultivar Express [52].…”

“…In addition, adultplant resistance to stripe rust controlled by a single gene or QTL was reported in wheat genotypes "Bersee" as Yr16 [61], in "Pavon F76" as Yr29 [62], in wheat genotype "Lgst. 79 -74" as Yrns-B1 [63], in "Opata 85" as Yr30 [64], in "Cook" [65], in a T. boeoticum transgressed wheat genotype as QYrtb.pau-5A and a T. monococcum transgressed wheat line as QYrtm.pau-2A [66], and in wheat genotype "Aquileja" [21]; and by three genes or QTL was reported in "Guardian" [67]. In winter wheat "IDO444", HTAP resistance is controlled by two major QTL and three minor QTL [56].…”

“…The genes mapped to the same chromosomal arm have possibility to be the same gene. For example, QYrlo.wgp-2BS in spring wheat Louise and one of the QTL in winter wheat Luke may be the same gene as both cultivars have Brevor in their pedigree (Figure 2) and share the SSR marker Xgwm148 in their linkage groups [21,30]. The possibility that QYrex.wgp-1BL in Express and Yr29 in "Pavon F76" are the same gene could not be ruled out [52].…”