Comparative proteomic and transcriptional profiling of a bread wheat cultivar and its derived transgenic line over-expressing a low molecular weight glutenin subunit gene in the endosperm

In this paper, a parallel transcriptional and proteomic comparison of seeds from a transformed bread wheat line that over-expresses a transgenic low molecular weight glutenin subunit gene relative to the corresponding non-transformed genotype, has been carried out. Proteomic analyses showed that, during seed development, several classes of endosperm proteins were differentially accumulated in the transformed endosperm. As a result of the strong increase in the amount of the transgenic protein, the endogenous glutenin subunit, all sub-classes of gliadins, and metabolic as well as Chloroform/Methanol soluble proteins were diminished in the transgenic genotype. The differential accumulation detected by proteomic analyses, both in mature and developing seeds, was paralleled by the corresponding changes in transcript levels detected by microarray experiments. Our results suggest that the most evident effect of the strong over-expression of the transgenic glutenin gene consists in a global compensatory response involving a significant decrease in the amounts of polypeptides belonging to the prolamin superfamily. It is likely that such compensation is a consequence of the diversion of amino acid reserves and translation machinery to the synthesis of the transgenic glutenin subunit.Italian Minister for University and Research (MIUR), projects “Gene expression and accumulation of agronomically important proteins in plant cells: transcriptional and post-transcriptional mechanisms” (FIRB RBNE01TYZF), and “Evaluation of the presence of potentially nutritional and/or allergenic proteins in commercial and transgenic wheat endosperms and their characterization” (PRIN 2006)