Identification of novel high molecular weight glutenin subunit mutants in bread wheat (Triticum aestivum L.)

Bread wheat (Triticum aestivum L.) is a staple food crop eaten in different ways like pan and other food products. High molecular weight glutenin subunits (HMW­GS) are major determinants of the different wheat end­use qualities. Ethyl­methanesulfonate (EMS) mutagenized populations in plants can be used for the discovery of valuable mutants for basic research and breeding purposes. In this study, we report the identification of 27 HMW­GS M3 mutants based on SDS­PAGE patterns from an EMS mutagenized population of the cultivar Baguette Premium 11. Nine mutations were detected in Ax2*, five in Bx7, four in By8, six in Dx5 and three in Dy10 subunit. Two Ax2* null mutants were characterized at molecular level finding in both cases premature stop codons associated. EMS would tend to generate more premature stop codons in glutenins genes than in others because these have a high frequency of glutamine codons. This type of mutation generates null alleles, therefore they are easily detectable by a low cost protocol like SDS­PAGE. The potential use of knock­out (null alleles) and SDS­PAGE size altered mutants for HMW­GS in wheat quality and nutrition is discussed.

Keywords: wheat, glutenins, mutagenesis, plant breeding