Genome-wide dissection of lesion mimic mutations in wheat: identification and functional characterization of candidate genes.

Lesion mimics (LMs), characterized by spontaneous necrotic spots in plants without pathogen infection, are associated with abnormal immune system activation and play a pivotal role in deciphering plant immune networks. This study employed an integrated GWAS and QTL strategy, genotyping 349 association panel accessions using the Wheat 660 K SNP array and 181 linkage population lines using the Wheat 55 K SNP array. GWAS analysis identified a total of 696 significant SNPs that correspond to the 23 genetic loci associated with lesion mimic formation, including 10 consistently detected in all replicates with PVE of 13.17% to 27.29%. QTL mapping revealed 10 lesion mimic loci with loci qLM-7A.1 and qLM-7D co-detected by both approaches. Subsequently, 22 candidate genes were identified through homologous BLAST analysis using cloned lesion mimic genes from Arabidopsis and rice as references. Haplotype analysis of natural polymorphisms identified three high-confidence genes significantly associated with lesion mimic phenotypes. These findings not only provide novel targets for disease resistance breeding but also establish a methodological framework for investigating complex trait genetics in polyploid crops.