Roots, cycles and leaves. Expression of the phosphoenolpyruvate carboxylase kinase gene family in soybean

• Published in: Plant physiology (Bethesda) Vol. 135; no. 4; pp. 2078 - 2087
• Main Authors: Sullivan, S, Jenkins, G.I, Nimmo, H.G
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01-08-2004; American Society of Plant Physiologists
• Subjects: Amino Acid Sequence; amino acid sequences; Arabidopsis; Base Sequence; Biochemical Processes and Macromolecular Structures; Biological and medical sciences; circadian rhythm; Complementary DNA; Darkness; DNA Primers; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Genes; Genomics; Glycine max; Glycine max - classification; Glycine max - enzymology; Glycine max - genetics; Leaves; Light; messenger RNA; Metabolism; Molecular Sequence Data; Multigene Family; Nodules; nucleotide sequences; phosphoenolpyruvate carboxylase; phosphoenolpyruvate carboxylase kinase; Phosphorylation; Photosynthesis, respiration. Anabolism, catabolism; Phylogeny; Plant Leaves - enzymology; Plant physiology and development; plant proteins; Plant Proteins - genetics; Plant Roots - enzymology; plant tissues; Plants; protein kinases; protein phosphorylation; Protein Serine-Threonine Kinases - genetics; Reverse Transcriptase Polymerase Chain Reaction; root nodules; roots; Sequence Alignment; sequence analysis; Sequence Homology, Amino Acid; serine-threonine protein kinases; Soybeans; Ubiquitin - metabolism; Ubiquitins; Plant tissue; Phosphorylation; Enzyme; Lyases; Circadian rhythm; Gene expression; Glycine max; Structure function relationship; Carbon-carbon lyases; Leguminosae; Gene; Carboxy-lyases; Dicotyledones; Angiospermae; Spermatophyta; Phosphoenolpyruvate carboxylase
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.104.042762

Phosphorylation of phosphoenolpyruvate carboxylase (PEPc; EC 4.1.1.31) plays an important role in the control of central metabolism of higher plants. This phosphorylation is controlled largely at the level of expression of PEPc kinase (PPCK) genes. We have analyzed the expression of both PPCK genes and the PEPC genes that encode PEPc in soybean (Glycine max). Soybean contains at least four PPCK genes. We report the genomic and cDNA sequences of these genes and demonstrate the function of the gene products by in vitro expression and enzyme assays. For two of these genes, GmPPCK2 and GmPPCK3, transcript abundance is highest in nodules and is markedly influenced by supply of photosynthate from the shoots. One gene, GmPPCK4, is under robust circadian control in leaves but not in roots. Its transcript abundance peaks in the latter stages of subjective day, and its promoter contains a sequence very similar to the evening element found in Arabidopsis genes expressed at this time. We report the expression patterns of five PEPC genes, including one encoding a bacterial-type PEPc lacking the phosphorylation site of the plant-type PEPcs. The PEPc expression patterns do not match those of any of the PPCK genes, arguing against the existence of specific PEPc-PPCK expression partners. The PEPC and PPCK gene families in soybean are significantly more complex than previously understood.