Genetic Mapping of a Triticum monococcum‐derived Powdery Mildew Resistance Gene in Common Wheat

Abstract

Powdery mildew of wheat (Triticum aestivum L.) is a major fungal disease caused by Blumeria graminis DC f. sp. tritici A microsatellite linkage map was developed for the T. monococcum‐derived powdery mildew resistant gene present in the North Carolina germplasm line NCBGT96A6 (NCA6). Genetic analysis of F2‐derived lines from the cross NCA6 × ‘Saluda’ indicated a single gene controlled powdery mildew resistance. Four microsatellite markers linked to the NCA6 Pm gene mapped to chromosome 7AL. The most likely order was Xcfa2123‐0.9 cM–Xbarc121‐1.7 cM resistance gene/Xcfa2019‐3.0 cM‐Xgwm332 A detached‐leaf test indicated the disease reaction response of the NCA6 Pm gene was different from the five known alleles at the Pm1 locus on 7AL. Deletion interval mapping showed a large physical to genetic distance ratio for these microsatellite marker loci. This may be due to suppressed recombination between the introgressed T. monococcum segment and the homologous region of the T. aestivum cultivar Saluda. Our results suggested that the NCA6 Pm gene is likely a novel source of resistance to powdery mildew but additional allelism studies are needed to establish the relationship between this locus and the other known Pm loci on 7AL.

Fine mapping of powdery mildew resistance genes PmTb7A.1 and PmTb7A.2 in Triticum boeoticum (Boiss.) using the shotgun sequence assembly of chromosome 7AL

“…However, with the additional markers developed from NextGen shotgun sequence assembly (IWGSC 2014), we identified a robust RGA-STS marker Ta7AL_4556232_rga which is only 0.6 cM from PmTb7A.1. 3), whereas NCA6Pm co-segregated with Xcfa2019 as reported by Miranda et al (2007). PmTb7A.1 in the present study maps 4.6 cM proximal to Xcfa2019 (Fig.…”

“…Breeding cultivars with inherent resistance is the most promising approach to manage this disease. The diploid 'A' genome species, Triticum monococcum ssp monococcum (T. monococcum-A m A m ), T. monococcum ssp aegilopoides (Triticum boeoticum-A b A b ) and Triticum urartu (A u A u ), harbour useful variability for many economically important genes, including resistance to diseases (Feldman and Sears 1981;Dhaliwal et al 1993;Hussien et al 1997;Miranda et al 2007;Singh et al 2007a;Chhuneja et al 2008;Singh et al 2010). Till date, more than 73 powdery mildew resistance genes/alleles have been identified at 50 loci (Pm1-Pm54; Pm18 = Pm1c, Pm22 = Pm1e, Pm23 = Pm4c, Pm31 = Pm21) in wheat and its wild relatives (McIntosh et al 2013;Xiao et al genome and 13 on the D genome of wheat.…”

“…Till date, more than 73 powdery mildew resistance genes/alleles have been identified at 50 loci (Pm1-Pm54; Pm18 = Pm1c, Pm22 = Pm1e, Pm23 = Pm4c, Pm31 = Pm21) in wheat and its wild relatives (McIntosh et al 2013;Xiao et al genome and 13 on the D genome of wheat. Other two genes designated as NCA6 Pm and PmU have been transferred form T. monococcum and T. urartu, respectively (Qiu et al 2005;Miranda et al 2007). ovata, Ae.…”

MlUM15: an Aegilops neglecta‐derived Powdery Mildew Resistance Gene in Common Wheat

“…Previous studies using six or fewer CS deletion lines mapped the physical location of the Pm1 locus to a terminal deletion bin (0.86-1.00) of chromosome 7AL ( Ji et al, 2008;Miranda et al, 2007b;Sourdille et al, 2004). The inclusion of more deletion lines provided further information about the precise physical location of the Pm1 complex and other Pm genes on chromosome 7AL: Pm1 and closely linked flanking markers Xcfa2257, Xcfa2240, Xmag2185, IWA2929, and IWA4434 were mapped to a narrower terminal deletion bin (0.99-1.00).…”

“…The following lines each bear one of the five Pm1 alleles: 'Axminster' (Pm1a) (Sears and Briggle, 1969), 'MocZlatka' (Pm1b) (Hsam et al, 1998), 'M1N' (Pm1c) (Hsam et al, 1998), T. spelta (Pm1d) (Hsam et al, 1998), and 'Virest' (Pm1e) (Singrün et al, 2003). Additional lines tested were NC99BGTAG11 (NC-AG11) (Pm37) (Perugini et al, 2008;Srnic´ et al, 2005), NC96BGTA4 (PmNCA4) (Srnic´ et al, 2005); NC96BGTA6 (PmNCA6) (Miranda et al, 2007b), and NC06BGTAG12 (NC-AG12) (MlAG12) (Maxwell et al, 2009). The germplasm lines TA391 (PmTb7A.1 and PmTb7A.2) (Chhuneja et al, 2012), and TA2033 (Mlm2033) (Yao et al, 2007), obtained from the Wheat Genetics Resource Center at Kansas State University, contain genes with temporary designations.…”