Comparative proteomic analysis of starch granule proteins of two durum wheat cultivars and their derived transgenic lines

In wheat, starch branching enzymes IIa (SBEIIa) play an important role in starch biosynthesis; in fact the modulation of their activity has a pronounced effect on the amylose content with important consequences on the nutritional and technological properties of end products such as bread and pasta. Recently, with the aim to increase amylose content, Sestili et al. [1] have silenced genes coding SBEIIa by RNA interference (RNAi) in two durum wheat cultivars (Svevo and Ofanto) using two different methods of transformation (biolistic for Svevo and Agrobacterium for Ofanto). The RNAi transgenic lines showed a strong increase of amylose content (up to more than 70%) and several pleiotropic effects at gene expression level. In this work two transgenic lines, one derived from cv Svevo (MJ16-112) and one from cv Ofanto (A431_4p1a), have been used to evaluate how expression of starch granule associated proteins of immature (15 DPA) and mature grain (36 DPA) is influenced by the silencing of SBEIIa genes, by using a proteomic comparison. Differentially expressed spots between transgenic and control lines have been identified and analyzed by mass spectrometry. The majority of the polypeptides, as expected, resulted to be involved in starch biosynthesis. Moreover, the comparison of the two different methods of transformation has not showed significant differences in starch granule proteins of the two transgenic lines.