Cloning and prokaryotic expression of a cDNA encoding a putative mitochondrial malate dehydrogenase in Oryza sativa.

Malate dehydrogenase (MDH) has been characterized as a key player in oxaloacetate (OAA) biosynthesis mechanism in citrate acid cycle that generates reducing powers for further assimilation in the whole cell. Here we present the cloning, characterization and prokaryotic expression of a putative Mdh (OsmMDH) in Oryza sativa. Sequence alignment shows that there is a high homology between the deduced amino acid sequence of OsmMDH and MDH portein in Eucalyptus gunnii (80%), as well as between the deduced amino acid sequence of OsmMDH and other MDHs. Moreover, pI and the mitochondrial location of OsmMDH are predicted. The tissue-specific expression pattern of OsmMDH reveals that it is abundant in young panicle and immature seed, while its expression level is mush lower in leaf and root. Its expression in E. coli BL21 as a fusion gene is studied further.