Genome-wide association study of novel genetic loci for cadmium accumulation and germplasm screening for low-cadmium accumulation in common wheat (Triticum aestivum L.)

1. Identification of 30 core QTLs for wheat Cd accumulation. 2. Genome-wide analysis reveals four potential candidate genes. 3. Development of two KASP markers for breeding selection. Cadmium (Cd) contamination in wheat farmland is increasing at an alarming rate, posing threats to food security and public health. Breeding and utilizing wheat varieties characterized by low Cd accumulation levels constitute an effective strategy in the battle against wheat Cd contamination. The adoption of molecular marker-assisted approaches can greatly expedite the selection and enhancement of wheat varieties with low Cd accumulation. Nonetheless, research concerning genes associated with wheat cadmium accumulation remains scarce. In this study, a high-density 660K SNP array was employed for conducting genome-wide association studies (GWASs) on the grain Cd concentration (GCdC), bioconcentration factor (BCF) and translocation factor (TF) in 175 wheat germplasms. The findings revealed 401 significant SNPs identified across three diverse environments. Linkage disequilibrium analysis revealed 30 core quantitative trait locus (QTLs)capable of reliably modulating wheat Cd accumulation phenotypes. Through gene annotation, transcriptomics, and gene molecular features, four candidate genes ( TraesCS7B02G000200, TraesCS4A02G035900, TraesCS4A02G040900, TraesCS5D02G564000 ) were identified as potential constituents of the biological process of wheat Cd accumulation. Furthermore, in this study 6 wheat germplasms exhibiting low grain Cd accumulation were isolated, and two Kompetitive Allele Specific PCR (KASP) markers conducive to breeding selection were developed. These findings provide valuable genetic resources for cultivating wheat with low Cd accumulation and establish a foundation for understanding the molecular mechanisms underlying low Cd accumulation in wheat. The candidate genes and KASP markers elucidated in this research have potential for effective employmentuse in genetic enhancement and marker-assisted selection in the breeding of wheat with low Cd accumulation.