From Kernel to Kitchen: Asparagine Synthetase 3 is Involved in Free Asparagine Accumulation in Maize Kernels

Acrylamide is a probable dietary carcinogen formed through high-temperature cooking processes from one of its precursors, free asparagine (Asn). To reduce acrylamide formation potential in maize-based food products, the genetic basis for the accumulation of free Asn in maize kernels must be elucidated. In this study we integrated complementary quantitative genetic approaches including quantitative trait locus (QTL) mapping of a biparental population and genome-wide association studies (GWAS) in a diverse inbred panel. We ultimately identified one major QTL for free Asn which was not reflected in the GWAS results. Subsequent sequence analysis of the QTL mapping population parents revealed a 921bp deletion in As-paragine Synthetase 3 (ASN3) in the low Asn parent. Validation is underway with rtPCR, genotyping the association panel for the deletion, and evaluation of a CRISPR-Cas9 knockout of ASN3. This work provides a foundation for breeding and genome-editing strategies to reduce acrylamide-forming potential in maize-based foods.