Two-dimensional electrophoretic comparison of mitochondrial polypeptides from different wheat ( Triticum aestivum L.) tissues

Abstract

The protein compositions of mitochondria isolated from etiolated leaves, green leaves (photosynthetic or non-photosynthetic), roots and calli from Triticum aestivum L. were compared by two-dimensional (2-D) gel electrophoresis. Qualitative and quantitative protein changes were observed between mitochondria from these tissues. When compared to etiolated leaves developed in the dark, mitochondria from leaves greened under natural light showed particularly important polypeptide changes i.e. the increase of four polypeptides belonging to the glycine decarboxylase complex (which is involved in the photorespiration phenomenon). Using non-photosynthetic green leaves developed under intermittent light (white light flashes separated by 15-min dark periods), it was shown that the quantitative increase of these four polypeptides was not correlated to efficient photosynthesis. Moreover, it was specified using a different condition of intermittent light (set of flashes separated by 24-h dark periods) leading to etiolated and of course non-photosynthetic leaves, that these polypeptide changes were not dependent on net chlorophyll synthesis. On the other hand, the analysis of mitochondrial protein composition from tissue culture has revealed some specific changes characteristic of callus. These changes were found whatever the tissue used to initiate the in vitro culture and were observed for some time in leaf mitochondria isolated from regenerated plants maintained in vitro.