Identification and mapping stripe rust resistance gene YrLM168a using extreme individuals and recessive phenotype class in a complicate genetic background

Abstract

The identification and characterization of resistance genes effective against stripe rust of wheat is beneficial for modern wheat breeding programs. Molecular markers to such genes facilitate their deployment. The variety Milan has resistance that is effective against the predominant stripe rust races in the Sichuan region. Two resistant and two susceptible F8 lines from a cross between Milan and the susceptible variety Chuannong 16 were used to investigate inheritance of the Milan resistance. Three F2 populations were developed from crosses between the resistant lines and their susceptible sibling lines (LM168a × LM168c, LM168c × LM168a, LM168b × LM168d) and used for genetic analysis and molecular mapping of the genes for resistance. The stripe rust resistance in LM168a and LM168b was conferred by a single dominant gene, temporarily designated as YrLM168a. Forty-five extreme susceptible plants from the F2 families of LM168d × LM168b were genotyped with 836 simple sequence repeat (SSR) markers to map YrLM168a. YrLM168a was mapped in chromosome 6BL. The nearest flanking markers Xwmc756 and Xbarc146 were 4.6 and 4.6 cM away from the gene at both sides, respectively. The amplification results of twenty extreme resistant (IT 0) and susceptible (IT 4) F2 plants of LM168c × LM168a and LM168a × LM168c with marker Xwmc756 further validated the mapping results. The study suggested that extreme individuals and recessive phenotype class can be successfully used for mapping genes, which should be efficient and reliable. In addition, the flanking markers near YrLM168a should be helpful in marker-assisted breeding.

Genome-Wide QTL Mapping for Stripe Rust Resistance in Winter Wheat Pindong 34 Using a 90K SNP Array

“…To date, more than nine QTLs/genes for stripe rust resistance have been reported on chromosome 6BL by genetic populations and GWAS analysis. For example, YrLM168a (derived from wheat resistance line LM168a, nearest flanking markers Xwmc756 and Xbarc146 , Feng et al, 2015a ) confers all-stage resistance and QYrdr.wgp-6BL.2 (derived from winter wheat Druchamp, most closely associated with SNP marker IWA6420 ) confers HTAP resistance (Hou et al, 2015 ). QYrdurum-6BL was derived from durum wheat and was linked with the SNP marker IWB72946 (Liu et al, 2017 ).…”

Mapping QTL for Adult-Plant Resistance to Stripe Rust in a Chinese Wheat Landrace

“…QYr.sdau-6B was identified on chromosome 6B in this study. Using the integrated genetic map of chromosome arm 6BL, six YR APR genes or QTLs were mapped at the similar position, including QYr.pav-6BL [ 30 ], QYr.inra-6BL [ 31 ], YrLM168a [ 32 ], QYrdr.wgp-6BL.2 [ 33 ], QYr.ucw [ 34 ], and QYr.nwafu-6BL [ 35 ]. Among those reported QTLs, YrLM168a , QYr.pav-6BL , QYr.inra-6BL , and QYrdr.wgp-6BL.2 overlapped with the QYr.sdau-6B between 500.6 Mb and 598.5 Mb ( Table 2 ), thus they are most likely the same QTL for YR resistance.…”

Fine Mapping of the Wheat Leaf Rust Resistance Gene LrLC10 (Lr13) and Validation of Its Co-segregation Markers

“…RCA has been proven to map genes efficiently and reliably (Zhang et al, 1994;Yao et al, 1997;Mei et al, 1999;Chen et al, 2006;Kiswara et al, 2014). In wheat, rapid gene mapping using RCA has been used to map a sterile female gene (Dou et al, 2009) and a stripe rust resistance gene, YrLM168a (Feng et al, 2015), and to successfully map and clone the powdery mildew resistance gene Pm60 (Zou et al, 2018).…”