Induced mutations in ASPARAGINE SYNTHETASE-A2 reduce free asparagine concentration in the wheat grain

Acrylamide is a neurotoxin and probable carcinogen formed as a processing contam-inant during baking and production of different foodstuffs, including bread products.The amino acid asparagine is the limiting substrate in the Maillard reaction thatproduces acrylamide, so developing wheat (Triticum aestivumL.) cultivars withlow free asparagine concentrations in the grain is a promising approach to reducedietary acrylamide exposure. A candidate gene approach was used to identify chemi-cally induced genetic variation inASPARAGINE SYNTHETASE 2(ASN2) genes thatexhibit a grain-specific expression profile. In field trials, durum and common wheatlines carryingasn-a2null alleles exhibited reductions in free asparagine concentra-tion in their grains of between 9 and 34% compared with wildtype sister lines. Theseplants showed no significant differences in spikelet number, grain size and weight,germination or baking quality traits. These nontransgenic variants can be deployedwithout regulatory oversight in elite wheat germplasm to reduce acrylamide-formingpotential with no negative effects on quality or agronomic performance.