Novel genomic regions associated with adult-plant resistance to multiple fungal pathogens in wheat (Triticum aestivum L.) revealed by DArT marker sequencing.
Wheat is among the top three most important cereal crops globally and serves as a staple food for approximately 40% of the world's population. Fungal leaf diseases such as yellow and leaf rusts (YR, LR), septoria nodorum blotch (SNB), septoria tritici blotch (STB), and powdery mildew (PM) have a major effect on yield loss in wheat, and resistance breeding is so far the most effective strategy to minimize those losses. Adult plant resistance (APR) is a crucial component of durable disease resistance; it reduces the pathogen's infection rate, keeping disease levels below the damage threshold, even in the absence of complete immunity. Therefore, this study aimed to identify sources of resistance in a collection of 411 accessions from diverse global origins. These accessions were phenotyped across 2018-2019. DArTseq technology and Genome-wide association studies (GWAS) analysis were conducted to identify single-nucleotide polymorphisms (SNPs) associated with APR for evaluated pathogens. DArT analysis showed that wheat chromosome 2B contains genomic regions associated with resistance to SNB, and that SNPs on chromosome 3B are associated with resistance to YR. On chromosome 6 A, there is a strong potential to explore, as a shared resistance locus for YR and SNB was found. SNPs: 3,937,236, 1,056,817 were consistent in both years, meaning their association with disease resistance is reliable and repeatable. Chromosome 7D is a strong region for SNPs significantly associated with both LR and SNB resistance. While multiple disease resistance genes are present on 7D, the 610 Mb LR locus is distinct from known LR, PM, and SNB loci, making it a strong candidate for functional validation. These findings highlight the value of historical resistance sources and uncover novel genomic regions for breeding a broad-spectrum APR-based resistance. Dual-trait loci, especially those effective against both biotrophic and necrotrophic pathogens, represent a promising material for achieving durable resistance in elite wheat cultivars.