Abstract
It is thought that 2-oxoglutarate (2-OG)/malate transporter (OMT) and general dicarboxylate transporter (DCT) in the inner plastidic envelope membrane cooperatively function in import of cytosolic 2-OG generated from TCA cycle and photorespiration, and export of Glu generated from stromal GS/GOGAT cycle. Therefore, the OMT/DCT transport system is thought to play an important role in mediating between carbon and nitrogen metabolic pathways. Because Arabidopsis OMT knockout plant showed slightly delay of growth, we measured metabolite levels in the leaf tissues. The levels of 2-OG and citrate were lower in the knockout plant compared with wild-type plant. Although some amino acids (Glu, Asp, Ala and Ser) were decreased, Gln was abundantly accumulated in the mutant. The knockout plant showed more prominent photoinhibition than wild-type plant under the high-light stress condition. We will discuss on the importance of OMT in the light of carbon and nitrogen metabolisms, and transport of reducing equivalents.
