Quantitative trait loci analysis for resistance to Cephalosporium stripe, a vascular wilt disease of wheat

Abstract

Cephalosporium stripe, caused by Cephalosporium gramineum, can cause severe loss of wheat (Triticum aestivum L.) yield and grain quality and can be an important factor limiting adoption of conservation tillage practices. Selecting for resistance to Cephalosporium stripe is problematic; however, as optimum conditions for disease do not occur annually under natural conditions, inoculum levels can be spatially heterogeneous, and little is known about the inheritance of resistance. A population of 268 recombinant inbred lines (RILs) derived from a cross between two wheat cultivars was characterized using field screening and molecular markers to investigate the inheritance of resistance to Cephalosporium stripe. Whiteheads (sterile heads caused by pathogen infection) were measured on each RIL in three field environments under artificially inoculated conditions. A linkage map for this population was created based on 204 SSR and DArT markers. A total of 36 linkage groups were resolved, representing portions of all chromosomes except for chromosome 1D, which lacked a sufficient number of polymorphic markers. Quantitative trait locus (QTL) analysis identified seven regions associated with resistance to Cephalosporium stripe, with approximately equal additive effects. Four QTL derived from the more susceptible parent (Brundage) and three came from the more resistant parent (Coda), but the cumulative, additive effect of QTL from Coda was greater than that of Brundage. Additivity of QTL effects was confirmed through regression analysis and demonstrates the advantage of accumulating multiple QTL alleles to achieve high levels of resistance.

Identification of Cephalosporium stripe resistance quantitative trait loci in two recombinant inbred line populations of winter wheat

“…Another class of defense-associated proteins is composed of serine/threonine protein kinase (S/TPK) domain (Faris et al 2010;Lorang et al 2007). They reported a QTL in chromosome 5AL that is located in the same region as 5AL.1 for Cephalosporium stripe found in E/T, T/N populations and in C/B (Quincke et al 2011). Lillemo et al (2013) reported a QTL for the necrotrophic pathogen spot blotch (Bipolaris sorokiniana, telemorph Cochliobolus sativus) that co-locates to the locus Lr34, which provides resistance to leaf rust (Puccinia triticina Eriks).…”

“…This region was identified previously (Quincke et al 2011), located close and probably pseudo-linked to the B1 gene conditioning the awnless trait (Kato et al 1998). The QTL 5AL.1 linked to marker gwm291 was detected consistently across environments in both populations, making it a good candidate for use in marker-assisted selection.…”

“…In a previous study, Quincke et al (2011) performed a QTL analysis on a recombinant inbred line (RIL) population with two commonly grown Pacific Northwest USA winter wheat cultivars, Coda/Brundage (C/B) that varied for resistance to Cephalosporium stripe. The identification of molecular markers associated with Cephalosporium stripe resistance would allow for genotypic selection of resistant genotypes.…”

Mapping Stripe Rust Resistance in a BrundageXCoda Winter Wheat Recombinant Inbred Line Population

“…The Brundage by Coda population has previously been genotyped using SSR (simple sequence repeat; Xbarc , Xpsp , Xwmc , Xgwm , Xgdm ) and DArT (Diversity Array Technology; wPt ) genetic markers as described in Quincke et al [22], Johnson et al [23] and Leonard et al [21]. Single nucleotide polymorphism (SNP) markers ( Xiwa ) were evaluated on the population using the Illumina GoldenGate assay as described by Akhunov et al [31] and Cavanagh et al [32].…”

“…The soft white winter wheat ( T. aestivum L.) mapping population created from the cross ‘Brundage’ (PI 599193) by ‘Coda’ (PI 594372) at the University of Idaho has been used to map several traits including Pch1 resistance to eyespot caused by Oculimacula yallundae [21], Cephalosporium stripe caused by Cephalosporium gramineum [22], and the compactum locus [23]. The population also segregates for resistance to stripe rust.…”