Genetic Dissection of the Powdery Mildew Resistance in Wheat Breeding Line LS5082 Using BSR-Seq

Abstract

Wheat powdery mildew is a destructive disease seriously threatening yield and quality. Comprehensive dissection of new resistance-related loci/genes is necessary to control this disease. LS5082 is a Chinese wheat breeding line with resistance to powdery mildew. Genetic analysis indicated that a single dominant gene, tentatively designated PmLS5082, conferred seedling resistance to different Bgt isolates. Bulked segregant RNA-seq (BSR-seq) was carried out to map the R gene PmLS5082 and profile differentially expressed genes associated with PmLS5082. PmLS5082 was mapped to chromosome arm 2BL and flanked by the markers WGGBH612-5 and YTU19-005 with genetic distances of 0.3 and 0.4 cM, respectively. The physical position was subsequently locked into the interval of 710.3-711.0 Mb. PmLS5082 differs from the catalogued Pm genes on chromosome arm 2BL in its resistant spectrum, physical position and origin, suggesting it is most likely a new Pm gene. Through COG and KEGG analysis, differentially expressed genes associated with PmLS5082 were profiled, and six genes in PmLS5082 interval were confirmed to be associated with PmLS5082 via RT-qPCR, using an additional set of wheat samples and time-course analysis post-inoculation with Bgt. In order to transfer PmLS082 to different genetic backgrounds using marker-assisted selection (MAS), closely linked markers, including Kompetitive Allele-Specific PCR (KASP) markers, were evaluated and nine markers were confirmed to be widely applicable for MAS in different genetic backgrounds.

PmSN15218: A Potential New Powdery Mildew Resistance Gene on Wheat Chromosome 2AL

“…At present, more than 100 powdery mildew-resistance genes or alleles mapping to 63 different loci ( Pm1 – Pm68 , Pm18 / Pm1c , Pm22 / Pm1e , Pm23 / Pm4c , Pm31 / Pm21 , Pm48 / Pm46 , and Pm17 / Pm8 ) have been reported, with the loci Pm1 , Pm3 , Pm4 , Pm5 , and Pm24 having 5, 17, 8, 5, and 2 alleles, respectively ( Li et al, 2020 ; McIntosh et al, 2020 ; He et al, 2021 ; Zhang et al, 2021 ; Wu et al, 2022 ). These include five resistance alleles, Pm4a – Pm4e , reported at the locus Pm4 , located on the long arm of chromosome 2A.…”