Precise mapping and candidate gene identification of the Rmd_JY47 locus conferring resistance to powdery mildew in soybean

Powdery mildew (PM), caused by Erysiphe diffusa , is a major constraint on soybean production worldwide. Host resistance is central to PM management, yet, the scarcity of durable resistance genes limits breeding process. In this study, a quantitative trait locus, Rmd_JY47 with a logarithm-of-odds score of 7.19 and a phenotypic contribution rate of 9.65 % was identified at the distal end of chromosome 16 (967.6-Kb) utilizing a dense genetic map constructed from 276 recombinant inbred lines originating from parental strains displaying resistance and susceptibility. Within this region, 85 candidate genes were identified, including 25 encoding LRR-RLP or RLKs and four RNA or DNA-binding proteins. Expression profiling after PM infection highlighted five genes— Glyma.16G167700 , Glyma.16G170900 , Glyma.16G171500 , Glyma.16G171700 , and Glyma.16G171800 —with significant differential expression and genetic variation between parental lines. These candidates likely function through LRR receptor-mediated immunity and post-transcriptional regulation, contributing to a layered defense response. The results provide valuable resources for marker-assisted selection and gene pyramiding, and offer insights into soybean– E. diffusa interactions to support molecular design breeding. • Rmd_JY47 , a major PM resistance QTL, was mapped via composite interval mapping. • Five differentially expressed candidate genes with functional variations were identified. • LRR receptor-mediated pattern-triggered immunity pathway may be involved in PM resistance mechanism. • Key molecular markers for marker-assisted selection in soybean PM-resistant breeding.