Changes in the composition and size distribution of endosperm proteins from bug-damaged wheats

Sivri D., Batey I., Skylas D., Daqiq L., Wrigley C.

AUSTRALIAN JOURNAL OF AGRICULTURAL RESEARCH, vol.55, no.4, pp.477-483, 2004 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 55 Issue: 4
  • Publication Date: 2004
  • Doi Number: 10.1071/ar03185
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.477-483
  • Hacettepe University Affiliated: No


In this study, grain that had been damaged by the bug Eurygaster spp. and/or Aelia spp., plus some undamaged grain, was selected from hard red winter (HRW) wheat. The changes in endosperm proteins were determined by 2-dimensional (2-D) electrophoresis and size-exclusion high-performance liquid chromatography (SE-HPLC). Although some new protein spots and a slight decrease in the staining intensities of some polypeptides were observed in the 2-D map of the bug-damaged sample, other parts of the gels were similar to the sound (control) sample in terms of relative mobilities and intensities of the polypeptide spots. The major difference between bug-damaged and control samples was that a group of polypeptides, presumably HMW-glutenins, shifted to a more basic region of the map. The SE-HPLC patterns of the total proteins extracted from control and bug-damaged samples in SDS-buffer showed that they differed in the size distribution of the polymeric glutenin protein and in their glutenin/gliadin ratios. The solubility of proteins in SDS buffer was greater in the bug-damaged sample. The 'unextractable' polymeric protein (only extractable in SDS-buffer after sonication) (UPP%) was significantly lower in the bug-damaged sample than in the control. The results of 2-D analysis and the decline in the quantity of unextractable proteins in SDS buffer suggest that bug-protease causes dough weakening by degradation of polymeric glutenin, presumably by hydrolysis, and possibly other mechanisms that affect the aggregation of the gluten molecules.