Two-dimensional electrophoresis and computer imaging analysis for the characterization of newly synthesized proteins in germinating durum wheat embryos

Exposure of wheat seeds, prior to radicle emergence, to cold and high temperature or to polyethylene glycol or NaCl stress is effective in controlling the germination process. Aging, induced by increasing seed moisture content, storage temperature and duration, also affects germination parameters. The newly synthesized protein patterns related to germination onset are also modified, as shown by 2-D electrophoresis separation of embryo soluble proteins, following [35S]-methionine in vivo incorporation. The qualitative and quantitative changes of one group of polypeptides, separated in the gel area with 5.9 - 5.4 pH isoelectric point and 75-54 MM range, have been studied using a computer imaging analysis. As time of radicle emergence increases depending on imbibitional stress severity, a variation of newly synthesized polypeptides, which is not specifically linked to overall germination inhibition, but is due to stress effect per se, can be observed. On the contrary, when changes in viability and germination onset are due to aging, a progressive decrease and increase of investigated polypeptides may be correlated with delay in germination onset. 2 - D gel electrophoresis, supported by computer imaging analysis, can provide a starting point for the characterization of newly synthesized proteins involved in specific phases of germination and embryo growth, and can be adapted for preparative purposes and microsequencing analysis.