Characterization of two 1D-encoded ω-gliadin subunits closely related to dough strength and pan bread-making quality in common wheat (Triticum aestivum L.) uri icon

abstract

  • Gliadin proteins of 113 common or bread wheat (Triticum aestivum L.) cultivars and advanced lines from China and other countries, were analyzed by high performance capillary electrophoresis (HPCE) and reversed-phase high performance liquid chromatography (RP-HPLC). A major protein peak migrating at 3 min by HPCE and eluting at about 20 min by RP-HPLC was identified in the omega-gliadin region. It was present in cultivars with good pan bread-making quality, whereas most cultivars with poor bread-making quality lacked this protein peak. Quality testing and statistical analysis showed that this omega-gliadin peak was significantly related to dough strength, loaf volume and loaf score. It was separated into two apparent protein components by one-dimensional SDS-PAGE and two-dimensional electrophoresis (2-DE). According to their relative mobilities on the gels, the proteins were designated omega-15 and omega-16, and their accurate molecular masses (42590.5 Da for omega-15 and 41684.1 Da for omega-16) were determined by MALDI-TOF-MS. The omega-15 and omega-16 gliadins possessed the N-terminal amino acid sequences of ARELNPSNKELQQQQ and KELQSPQQQF, and therefore they belonged to 1D-encoded omega-2 type and omega-1 type gliadins, respectively. Both gliadin subunits were always present together among the 86 cultivars analyzed, suggesting that they were encoded by two closely linked genes at Gli-D1 locus. The accumulative characteristics of gliadins during grain development indicated possible additive quantitative effects of omega-15 + 16 on dough strength. The omega-15 and omega-16 gliadins could be used as valuable genetic markers for wheat quality improvement. (C) 2007 Elsevier Ltd. All rights reserved.

publication date

  • 2008
  • 2008