Reduced free asparagine in wheat grain resulting from a natural deletion of TaASN-B2: investigating and exploiting diversity in the asparagine synthetase gene family to improve wheat quality

Abstract Background Understanding the determinants of free asparagine concentration in wheat grain is necessary to reduce levels processing contaminant acrylamide baked and toasted products. Although crop management strategies can help concentrations, breeders have limited options select for genetic variation underlying this trait. Asparagine synthetase enzymes catalyse a critical step biosynthesis plants and, wheat, are encoded by five homeologous gene triads that exhibit distinct expression profiles. Within family, TaASN2 genes highly expressed during development but TaASN-B2 absent some varieties. Results Natural diversity family was assessed different varieties revealing instances presence/absence other polymorphisms, including predicted affect function protein. The presence absence determined across range UK global common related species, showing deletion encompassing already present wild emmer genotypes. Expression profiling confirmed transcripts were only detectable grain, while TaASN3.1 early stages development. TaASN-A2 most homeologue assayed TaASN-D2 at similar, lower possessing . did not increase compensate TaASN-B2, so total lacking Consequently, concentrations field-produced were, on average, , although effect lost when accumulated very high as result sulphur deficiency. Conclusions Selecting genotypes may be simple rapid way commercial grain.