Molecular analysis of a tomato OGDH antisense line

Transgenic tomato (Solanum lycopersicum) plants expressing a fragment of the SlSIOGDH gene encoding subunit E1 of the 2-oxoglutarate dehydrogenase protein complex in the antisense orientation and exhibiting considerable reductions in the activity of this enzyme exhibit a considerably reduced rate of respiration. They were, however, characterised by largely unaltered photosynthetic rates and fruit yield but a restricted leaf, stem and root growth rate. The lines displayed markedly altered metabolic profiles including changes in tricarboxylic acid cycle intermediates and in the majority of the amino acids without alterations in pyridine nucleotide content. Moreover, they displayed a generally accelerated development exhibiting early flowering, accelerated fruit ripening and a markedly earlier onset of leaf senescence. In addition, transcript and selective hormone profiling of gibberellins and ABA revealed changes only in the former coupled to changes in transcripts encoding enzymes of gibberellins biosynthesis. The data obtained are discussed in the context of the importance of this enzyme in both photosynthetic and respiratory metabolism as well as in programs of plant development connected to carbon nitrogen interactions. Three biological replicates per genotype were analysed. Genotypes analyzed were tomato var. M82 wild type plants grown under green house conditions with one 2-oxo-glutarate dehydrogenase antisense line grown under the same conditions.