A key objective of wheat (Triticum aestivum) breeding is the simultaneous improvement of disease resistance and bread making quality. The Glu-V1 locus encoding the high-molecular-weight glutenin subunit (HMW-GS) V71 and the powdery mildew resistance gene Pm67 were previously identified on chromosome arm 1VS of the wild wheat species Dasypyrum villosum. Here, we generated the T1DL·1V#4S translocation line NAU195, which carried the V71 subunit for improved bread-making quality but was susceptible to all 18 isolates of the powdery mildew fungus Bgt examined. By contrast, the previously developed T1DL·1V#5S line NAU196 harbors the Pm67 gene conferring broad-spectrum powdery mildew resistance but lacks the V71 subunit. Genetic analysis of F₁ and F₂ progenies from a cross between NAU195 and NAU196 confirmed that Pm67 is a single dominant gene. By screening 2954 F₂ plants, we fine mapped Pm67 to an approximately 2.1 Mb interval on chromosome arm 1VS in the reference genome. We identified 35 high–confidence protein–coding genes in this region, including eight candidate genes encoding nucleotide binding site leucine rich repeat (NLR) proteins. We identified 12 recombinant T1DL·1VS translocation lines harboring both the V71 subunit and Pm67 genes, and introgressed one of the corresponding translocations into the high-yielding cultivar NMZ119. Plant development in the resulting T1DL·1VS translocation lines harboring the V71 subunit and Pm67 genes was comparable to that of NMZ119, with no significant yield penalty but with markedly improved powdery mildew resistance and gluten strength. Overall, our strategy for mapping and pyramiding alien genes in the common wheat background allowed us to generate a valuable genetic resource and molecular tool for accelerating the concurrent improvement of powdery mildew resistance and bread making quality.

Wheat sharp eyespot, a stem disease caused by the soilborne fungus Rhizoctonia cerealis van der Hoeven, has become a threat to wheat production worldwide. Exploiting resistance resources from wild relatives of wheat is a promising strategy for controlling this disease. In this study, a new wheat–Dasypyrum villosum T2DS·2V#4L translocation line in the background of Chinese Spring (CS) showed stable resistance to R. cerealis. Introgression of the T2DS·2V#4L chromosome into wheat cultivar Aikang 58 by backcrossing produced a marked increase in sharp eyespot resistance in NIL-T2DS·2V#4L in comparison with NIL-T2DS·2DL, and no detrimental effects of 2V#4L on agronomic traits were observed in the BC₂F₂, BC₂F_2:3, and BC₂F_2:4 generations. Flow-sorted sequencing of 2V#4L yielded 384.3 Mb of assembled sequence, and 8836 genes were predicted of which 6154 had orthologs in at least one of the 2AL, 2BL, and 2DL arms of CS, whereas 1549 genes were unique to 2V#4L. About 100,000 SNPs were detected in genes of 2V#4L and 2DL in 10 sequenced bread wheat cultivars. A Kompetitive Allele Specific Polymerase chain reaction and 30 conserved ortholog sequence markers were developed to trace the 2V#4L chromatin in wheat backgrounds. T2DS·2V#4L compensating translocation lines represent novel germplasm with sharp eyespot resistance and the markers will allow rapid detection in breeding programs.

Powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici (Bgt), is a global disease that poses a serious threat to wheat production. To explore additional resistance gene, a wheat-Dasypyrum villosum 1V#5 (1D) disomic substitution line NAU1813 (2n = 42) with high level of seedling resistance to powdery mildew was used to generate the recombination between chromosomes 1V#5 and 1D. Four introgression lines, including t1VS#5 ditelosomic addition line NAU1815, t1VL#5 ditelosomic addition line NAU1816, homozygous T1DL·1VS#5 translocation line NAU1817, and homozygous T1DS·1VL#5 translocation line NAU1818 were developed from the selfing progenies of 1V#5 and 1D double monosomic line that derived from F₁ hybrids of NAU1813/NAU0686. All of them were characterized by fluorescence in situ hybridization, genomic in situ hybridization, 1V-specific markers analysis, and powdery mildew tests at different developmental stages. A new powdery mildew resistance gene named Pm67 was physically located in the terminal bin (FL 0.70–1.00) of 1VS#5. Lines with Pm67 exhibited seedling stage immunity and tissue-differentiated reactions at adult plant stage. The sheaths, stems, and spikes of the Pm67 line were still immune, but the leaves showed a low degree of susceptibility. Microscopic observation showed that most penetration attempts were stopped in association with papillae on the sheath, and colonies cannot form conidia on the susceptible leaf of Pm67 line at adult plant stage, suggesting that the defence layers of the Pm67 line is tissue-differentiated. Thus, the T1DL·1VS#5 translocation line NAU1817 provides a new germplasm in wheat breeding for improvement of powdery mildew resistance.