Characterization of Two Adult‐Plant Stripe Rust Resistance Genes on Chromosomes 3BS and 4BL in Soft Red Winter Wheat

Abstract

Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss. (Pst), is an important foliar disease of soft red winter wheat (SRWW) (Triticum aestivum L.) in the eastern United States. However, very few resistance genes have been characterized in the SRWW germplasm pool. The SRWW line VA96W‐270 is known to be resistant to stripe rust race PST‐100, which was the predominant race in the United States from 2003 to 2006. To elucidate the genetic basis of resistance, a recombinant inbred line (RIL) population developed from a cross between VA96W‐270 and the susceptible cultivar Coker 9835 was evaluated for response to stripe rust infection in inoculated field nurseries over a 3‐yr period. The RIL population was then genotyped with stripe rust‐linked simple sequence repeat (SSR) markers and 90K single‐nucleotide polymorphism (SNP) markers. Two major quantitative trait loci (QTL) were identified, located on chromosomes 3BS and 4BL, both contributed by VA96W‐270. The 3BS and 4BL QTL explained up to 28 and 25% of the phenotypic variation for area under disease pressure curve (AUDPC), respectively. Recombinant inbred lines containing both QTL had average disease severity of 6%, compared with 38 to 45% for lines containing one of the two QTL and 69% for those containing neither QTL. Based on susceptibility of VA96W‐270 to infection at the seedling stage, the two genes appear to be associated with adult‐plant resistance. Markers associated with the two QTL were polymorphic in various wheat genotypes, suggesting they could be useful in marker‐assisted selection (MAS) to develop wheat cultivars with improved stripe rust resistance.

Fusarium Head Blight and Rust Diseases in Soft Red Winter Wheat in the Southeast United States: State of the Art, Challenges and Future Perspective for Breeding

“…Similarly, four biparental QTL mapping studies were conducted for adult plant SR resistance (Table 4) (Hao et al, 2011;Christopher et al, 2013;Subramanian et al, 2016;Carpenter et al, 2017). The first study utilized a RIL population (178 lines) and detected a major QTL on 2A, contributing up to 56% of phenotypic variation in the SRWW cultivars Pioneer 26R61 (Hao et al, 2011).…”

“…Of these, 2AS QTL explained up to 58.9% of phenotypic variation. The third study utilized a RIL population (146 RILs) and mapped two QTLs on chromosomes 3BS and 4BL (Subramanian et al, 2016). The fourth study utilized a RIL population (186 lines) and detected two QTLs for SR resistance in SRWW cultivar Jamestown in chromosomes 3B and 6A, contributing up to 11.1 and 14.3% of phenotypic variation, respectively (Carpenter et al, 2017).…”

Analysis of the primary sources of quantitative adult plant resistance to stripe rust in U.S. soft red winter wheat germplasm

“…In addition, the FAY13 and FAY14 environments were inoculated as described in Subramanian et al. (2016). Briefly, the FAY13 environment received artificial inoculation with a mixture of Pst isolates AR12‐21 and AR13‐01, and the FAY14 environment received artificial inoculation with isolate AR12‐25.…”

“…Yr17 has been defeated by most P. striiformis isolates in recent years including PSTv‐37, the most predominant isolate in the United States in the last decade (W. Liu et al., 2018). Several recent biparental QTL mapping studies have suggested that additional loci on chromosomes 3BS and 4BL also play an important role in stripe rust resistance in soft winter wheat (Christopher et al., 2013; Liu et al., 2019; Subramanian, Mason, Milus, Moon, & Brown‐Guedira, 2016), though the resistance genes underlying these loci still remain unidentified.…”

‘AR11LE24’, a Soft Red Winter Wheat Adapted to the Mid‐South Region of the USA

“…), and Fusarium head blight (caused by the pathogen Fusarium graminearum species complex). Similar to other regional breeding programs, there is a strong focus in the University of Arkansas Division of Agriculture's Wheat Breeding Program on breeding for improved and durable disease resistance (Milus et al, 2015; Subramanian et al, 2016).…”