INDUCED MUTATIONS IN TaASN-A2 REDUCE FREE ASPARAGINE CONCENTRATION IN THE WHEAT GRAIN

Acrylamide is a neurotoxin and probable carcinogen formed as a processing contaminant during baking and production of different foodstuffs, including bread products. The amino acid asparagine is the limiting substrate in the Maillard reaction that produces acrylamide, so developing wheat varieties with low free asparagine concentrations in the grain is a promising approach to reduce dietary acrylamide exposure. A candidate gene approach was used to identify chemically-induced genetic variation in ASPARAGINE SYNTHETASE 2 (ASN2) genes that exhibit a grain-specific expression profile. In field trials, durum and common wheat lines carrying asn-a2 null alleles exhibited reductions in free asparagine concentration in their grains of between 9 and 34% compared to wild-type sister lines. These plants showed no significant differences in spikelet number, grain size and weight, germination or baking quality traits. These non-transgenic variants can be deployed without restriction in elite wheat germplasm to reduce acrylamide-forming potential with no negative impacts on quality or agronomic performance. Core ideasO_LIThree wheat ASPARAGINE SYNTHETASE 2 knockout alleles were characterized in field experiments. C_LIO_LIMutant alleles conferred significant reductions in grain free asparagine concentration. C_LIO_LIThe alleles did not affect quality or agronomic traits. C_LIO_LIThese non-transgenic alleles can be deployed without restriction in wheat breeding programs. C_LI