Development and characterization of a novel compensating wheat-Dasypyrum villosum interstitial translocation line Dv6-IT1 carrying the powdery mildew resistance gene PmV.

key messageA novel compensating wheat-Dasypyrum villosuminterstitial translocation carrying an approximately 15-Mb alien segment harboring PmV was created and demonstrated normal inheritance powdery mildew resistance. The powdery mildew resistance gene PmV, derived from the diploid Dasypyrum villosum accession No.1026, was previously introgressed into common wheat via the T6V#4S·6DL translocation. However, severely reduced gamete transmission ratio limited its breeding utility. To address this limitation, a recombinant translocation line T6VS#4S-6V#2S·6AL with improved transmission ratio was previously created, then two smaller segmental translocations-Dv6T25 (T6VS-6AS·6AL, harboring 6VS 0-85 Mb) and Dv6T31 (T6AS-6VS·6AL, harboring 6VS 70-270 Mb), both carrying PmV-were generated using the ph1b induction system. In this study, homologous recombination within the overlapping region of Dv6T25 and Dv6T31 was utilized. A novel compensating interstitial translocation line Dv6-IT1 (T6AS-6VS-6AS·6AL) was identified, carrying an introgressed fragment of approximately 15 Mb, which exhibits normal meiotic transmission and confers no deleterious effects on plant height or spike number across different genetic backgrounds. The development of Dv6-IT1 provides a promising resistance source with minimal linkage drag for wheat powdery mildew breeding. This study not only addresses the long-standing transmission barrier associated with the original T6V#4S·6DL translocation but also significantly reduces linkage drag. Moreover, it establishes a model strategy for the precise introgression of wild species resistance genes into common wheat, paving the way for more efficient and sustainable wheat improvement against evolving pathogen threats.