Mapping of stripe rust resistance gene in an Aegilops caudata introgression line in wheat and its genetic association with leaf rust resistance

Abstract

A pair of stripe rust and leaf rust resistance genes was introgressed from Aegilops caudata, a nonprogenitor diploid species with the CC genome, to cultivated wheat. Inheritance and genetic mapping of stripe rust resistance gene in backcrossrecombinant inbred line (BC-RIL) population derived from the cross of a wheat-Ae. caudata introgression line (IL) T291- 2(pau16060) with wheat cv. PBW343 is reported here. Segregation of BC-RILs for stripe rust resistance depicted a single major gene conditioning adult plant resistance (APR) with stripe rust reaction varying from TR-20MS in resistant RILs signifying the presence of some minor genes as well. Genetic association with leaf rust resistance revealed that two genes are located at a recombination distance of 13%. IL T291-2 had earlier been reported to carry introgressions on wheat chromosomes 2D, 3D, 4D, 5D, 6D and 7D. Genetic mapping indicated the introgression of stripe rust resistance gene on wheat chromosome 5DS in the region carrying leaf rust resistance gene LrAc, but as an independent introgression. Simple sequence repeat (SSR) and sequence-tagged site (STS) markers designed from the survey sequence data of 5DS enriched the target region harbouring stripe and leaf rust resistance genes. Stripe rust resistance locus, temporarily designated as YrAc, mapped at the distal most end of 5DS linked with a group of four colocated SSRs and two resistance gene analogue (RGA)-STS markers at a distance of 5.3 cM. LrAc mapped at a distance of 9.0 cM from the YrAc and at 2.8 cM from RGA-STS marker Ta5DS_2737450, YrAc and LrAc appear to be the candidate genes for marker-assisted enrichment of the wheat gene pool for rust resistance.

Development of Wheat-Aegilops caudataIntrogression Lines and Their Characterisation Using Genome-Specific KASP Markers

“…caudata -derived powdery mildew resistant quantitative trait loci (QTL) were mapped onto chromosomes 1AS and 7AL of wheat (Weidner et al, 2012). Riar et al (2012) and Toor et al, (2016) mapped leaf rust and stripe rust resistance, respectively, onto chromosome 5DS of wheat in one wheat- Ae. caudata introgression line.…”

“…Ae. caudata carries resistance genes for several diseases (Makkouk et al, 1994), especially against stripe rust (Baldauf et al, 1992; Toor et al, 2016; Valkoun et al, 1985), leaf rust (Gong et al, 2017; Iqbal et al, 2007; Riar et al, 2012), stem rust (Dyck et al, 1990; Gong et al, 2017) and powdery mildew (Baldauf et al, 1992; Gill et al, 1985; Valkoun et al, 1985; Weidner et al, 2012) and resistance against pests such as greenbug and hessian fly (Baldauf et al, 1992; Gill et al, 1985). Moreover, some accessions of Ae.…”

“…caudata addition lines and the development of molecular markers capable of detecting Ae. caudata chromosomes in a wheat background, its utilisation for wheat improvement through recombination with wheat chromosomes has rarely been reported (Dyck et al, 1990; Iqbal et al, 2007; Riar et al, 2012; Toor et al, 2016; Weidner et al, 2012). In this work, we report the generation of six stable wheat- Ae.…”

Mapping the stripe rust resistance gene in Chinese wheat Guinong 775

“…2). Aegilops species are sources of stripe rust resistance genes, and partly resistant Aegilops genes have been introgressed into common wheat for the cultivation of cultivars with resistance to stripe rust 11 .…”

“…Aegilops species are important genetic sources for improving the variability of cultivated wheat, and formally designated resistance genes for stripe rust, such as Yr28, Yr17 and YrCH42, have been transferred to wheat from various Aegilops species 11 . Martynov et al demonstrated that the percentage of wheat varieties containing Aegilops genetic materials has gradually increased and that they have retained their effectiveness.…”