* Corresponding author: wujz@jaas.ac.cn

Common wheat is a crucial global food crop with a direct impact on food security. Wheat powdery mildew (PM), caused by Blumeria graminis f. sp. tritici (Bgt), poses a significant threat to wheat yield and flour quality. The identification and utilization of broad-spectrum resistance genes against PM are essential for effective disease control. The wheat landrace Honghuamai (HHM) has demonstrated remarkable resistance in adult plants in the field and high resistance to all 25 tested Bgt isolates during the seedling stage, making it a valuable source of powdery mildew resistance.

This study employed five genetic segregation populations to investigate the inheritance of PM resistance in HHM at both the seedling and adult stages. Genetic analysis showed that PM resistance in HHM is determined by a single dominant gene, temporarily named PmHHM.

By utilizing BSA separation analysis and molecular marker mapping, the gene was fine-mapped to a genetic distance of 0.0024 cM, corresponding to a physical interval of 242.5 kb based on the IWGSC v2.1. Seven high-confidence genes were predicted, with five of them annotated as RPP13-like proteins 1 clustering in the target region.

Comparative genomic analysis revealed the presence of presence/absence variations (PAVs) in the PmHHM region among genomes of different ploidy wheat and common wheat varieties, leading to varying recombination rates between populations. These closely linked molecular markers will not only benefit the cloning of PmHHM but also facilitate the efficient utilization of the gene in breeding.