Molecular and functional analyses support a role of ornithine-Δ-aminotransferase in the provision of glutamate for glutamine biosynthesis during pine germination

摘要: We report the molecular characterization and functional analysis of a gene (PsδOAT) from Scots pine (Pinus sylvestris) encoding Orn-δ-aminotransferase (δ-OAT; EC 2.6.1.13), an enzyme arginine metabolism. The deduced amino acid sequence contains putative N-terminal signal peptide for mitochondrial targeting. polypeptide is similar to other δ-OATs plants, yeast, mammals encoded by single-copy in pine. PsδOAT encodes δ-OAT as determined expression recombinant protein Escherichia coli active enzyme. was undetectable embryo, but highly induced at early stages germination seedling development all different organs. Transcript levels decreased later developmental stages, although increase observed lignified stems 90-d-old plants. An activity germinating embryos seedlings appears mirror alterations transcript levels. Similar patterns were also genes arginase isocitrate dehydrogenase. Transcripts found widely distributed cell types Consistent with these results metabolic pathway proposed nitrogen flow megagametophyte developing seedling, which supported relative abundance free acids seedlings. Taken together, our data support that plays important role this process providing glutamate glutamine biosynthesis during growth.