Proteomics as an emergent tool for identification of stress-induced proteins in control and genetically modified wheat lines

Proteomic methods have been used to identify stress-induced proteins that may have a special role in food science. A new challenge for proteomics has recently been recognised pointing out differences in food protein analysis relevant for nutrition. In this study application of proteomics for traceability of the effect of environmental changes on wheat proteins are addressed. The proteomic analysis involves excision of proteins of interest from two-dimensional (2D) gels, followed by reduction and digestion using trypsin in situ in the spot. The peptides are then analysed using MALDI (matrix assisted laser desorption/ionisation) mass spectrometry and identified by protein databases. The protein set of drought stressed wide-rage herbicide resistant transgenic spring wheat lines: 'T-117', 'T-106-3/a' and 'T-128' and of drought stressed non-transgenic (parent) spring wheat line: 'CY-45' was studied by 2-DE. The drought affected protein expression mostly for the low molecular weight, putative stress-induced proteins were observed in the molecular weight range 15-27 kDa at pH 6,5-7,5. The differentially expressed proteins of albumin and globulin fractions were digested from the gel and digested by trypsin. Number of inhibitor-like proteins were most dominant in the stressed transgenic lines: alpha-amylase/trypsin inhibitor CM1 precursor, alpha-amylase inhibitor, endogenous alpha-amylase/subtilisin inhibitor (WASI) and a 27 K protein, suggesting that the examined transgenic lines were the sensitive to drought stress.