Integrated genetic mapping and transcriptomic profiling reveal a broad-spectrum powdery mildew resistance locus from wild emmer wheat

Abstract Background Powdery mildew, caused by Blumeria graminis f. sp. tritici ( Bgt ), is a devastating wheat disease worldwide. Wild emmer wheat (WEW) harbors valuable resistance genes, yet most remain unexplored. The WEW accession CWI47098 exhibits stable broad-spectrum resistance to multiple Bgt isolates, but its genetic and molecular basis is unclear. Results Genetic analysis of F 1 , F 2 , and F 2:3 populations derived from a cross between CWI47098 and Langdon revealed that the resistance is governed by a single dominant gene, temporarily designated PmXP544 . Integrated bulked segregant RNA-seq (BSR-Seq) and linkage mapping localized PmXP544 to a 2.1 Mb interval (712.0-714.1 Mb) on chromosome arm 4AL, flanked by markers YTU540-019 and XWsdau73134.3 . Transcriptomic analysis identified 2,496 differentially expressed genes (DEGs) between resistant and susceptible bulks, of which 16 ones were located within the candidate interval and nine ones were functionally annotated as defense-related. GO and KEGG enrichment analyses revealed significant enrichment of photosynthesis-antenna proteins, phenylpropanoid biosynthesis, MAPK signaling, and glutathione metabolism, indicating multilayered immune reprogramming. A closely linked co-dominant marker YTUXP-35 exhibited broad applicability, supporting its utility for marker-assisted selection (MAS). Conclusion This study identifies a wild emmer wheat-derived Pm locus and provides breeding marker and transcriptomic insights for its future utilization in wheat resistance breeding.