Hordeum_vulgare ---- 4 Reseq
Leaf stripe disease, caused by the fungal pathogen Pyrenophora graminea, poses a significant threat to hulless barley (Hordeum vulgare var. coeleste) cultivation on the Qinghai-Tibet Plateau due to seed-borne transmission. This study aimed to investigate the genetic basis of resistance to this disease using an F3 population derived from a cross between the resistant landrace Guidemaqingke and the susceptible landrace Dulihuang. Genetic segregation analysis revealed that resistance in Guidemaqingke was controlled by a single dominant gene, provisionally designated Q-0106. Using bulked segregant analysis coupled with whole-genome resequencing (BSA-WGRS), we identified candidate genomic regions on chromosomes 2H and 3H. Further evaluation of single-nucleotide polymorphism (SNP) density and association significance refined the candidate locus to chromosome 3H. Among 102 Kompetitive Allele-Specific PCR (KASP) markers designed within the candidate interval, three validated markers (NC-522964284, NC-523254981, and NC-523268349) enabled the construction of a genetic linkage mapping for Q-0106. The resistance gene was found to be tightly linked to flanking markers NC-523254981 and NC-523268349, with genetic distances of 0.12 cM for both. High-resolution mapping localized Q-0106 to a 304-kb physical interval (NC_058520.1) between NC-523268349 and NC-522964284, spanning 0.25 cM. Within this critical region, four candidate resistance-associated genes were identified: XM_045118120.1, XM_045118121.1, XM_045121468.1, and XM_045121469.1. Comparative expression profiling via RT-qPCR highlighted XM_045118120.1 and XM_045121468.1 as the most promising candidates for Q-0106, as they exhibited distinct transcriptional regulation patterns consistent with disease resistance. This study provides foundational insights into molecular breeding strategies for leaf stripe resistance in hulless barley and offers robust genetic markers for marker-assisted selection.