Integrated GWAS and metabolomic analyses identified metabolic pathways and candidate genes involved in free asparagine accumulation in durum wheat grain

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 the natural variation in durum wheat to identify candidate genes controlling this trait. Durum wheat genotypes were selected from an international germplasm collection and sown in an experimental field in Italy for three years. Free asparagine content was measured on whole grain using an enzymatic assay. A genome-wide association study was performed, and six associated quantitative trait nucleotides were identified. Moreover, the whole grain metabolome of the durum wheat genotypes 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.