An improved MALDI-TOF mass spectrometry procedure and a novel DNA marker for identifying over-expressed Bx7 glutenin protein subunit in wheat

Wheat bread-making quality is mainly determined by glutenin proteins in the grain, which exist in a wide range of variable alleles with differential influence on processing attributes. A recently identified allele, Bx7 over-expression (Bx7^oe), has been showing highly significant positive effects on wheat dough strength over the normally expressed Bx7 allele. SDS-PAGE and normal RP-HPLC procedures failed to separate the two alleles. In the current study, an extensively optimised MALDI-TOF based procedure and a refined DNA based marker for efficiently differentiating Bx7^oe from normal Bx7 allele were established. Results indicated that the MALDI-TOF procedure is cost effective, high throughput, and proven reliable, while the refined PCR marker only amplifies Bx7^oe allele, a clear advantage over the previously developed codominant marker.