Dissecting the genetic architecture of microelement accumulation in wheat grains through genome-wide association study

• Using 176,357 RNA-Seq-based molecular markers, 196 significant loci associated with eight grain microelement contents were identified by GWAS in 272 wheat varieties. • The 14 significant markers were consistently identified across multi-environments, forming 13 stable QTLs that were linked to 45 candidate genes. • Haplotype analysis indicated TraesCS6A02G204300 Hap2 notably enhanced grain iron content. Wheat ( Triticum aestivum L.) is a vital staple crop globally, with its grain microelement content playing a crucial role in human nutrition and health. In this study, the concentrations of eight essential microelements (micronutrients and toxic elements): iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), selenium (Se), chromium (Cr), cadmium (Cd), and arsenic (As), were quantified in 272 wheat varieties using inductively coupled plasma mass spectrometry (ICP-MS) under three different environments. A genome-wide association study (GWAS) was conducted using 176,357 molecular markers, comprising 163,223 single-nucleotide polymorphisms (SNPs) and 13,134 insertion-deletion (InDels) variants, identified through RNA sequencing. A total of 196 significant markers associated with microelement content traits were identified across 21 chromosomes in various environments. Of these, 14 significant markers consistently appeared across environments, forming 13 QTLs and linking to 45 candidate genes. Among these, 29 genes were homologs of known genes in Arabidopsis and rice, while 16 were novel candidates. Haplotype analysis indicated significant phenotypic variation in microelement accumulation, with TraesCS6A02G204300 Hap2 notably enhancing iron content. This study provides valuable insights into the genetic architecture of microelement accumulation in wheat grains and introduces novel genetic resources for breeding wheat varieties aimed at improving micronutrient content and ensuring food safety.