Integrated GWAS and metabolomic analyses provide novel details about the genetic basis of free asparagine accumulation in durum wheat grains

Free asparagine content is a key factor in acrylamide formation in wheat derivatives after high temperature processing. Therefore, the control of free asparagine levels is of interest in crop and food sciences. Our study aims to explore free asparagine natural variation in durum wheat grain to identify candidate genes controlling this trait. Two hundred and one durum wheat genotypes were selected from an international germplasm collection and sown in an experimental field for three years. Free asparagine content was measured on whole grain using an enzymatic assay. A genome-wide association study identified six associated quantitative trait nucleotides. Moreover, the whole grain metabolome of one-year samples was investigated to identify metabolic pathways associated to free asparagine accumulation. Specific enriched pathways involved in amino acids metabolism were detected and four candidate genes were identified. This study paved the way to characterize the genetic determinants of free asparagine accumulation in wheat grain.