title: The evolution of pyrroline-5-carboxylate synthase in plants: a key enzyme in proline synthesis.
abstract: Many plants synthesize and accumulate proline in response to osmotic stress conditions. A central enzyme in the proline biosynthesis is the bifunctional enzyme Delta(1)-pyrroline-5-carboxylate synthase (P5CS) that includes two functional catalytic domains: the gamma-glutamyl kinase and the glutamic-gamma-semialdehyde dehydrogenase. This enzyme catalyzes the first two steps of the proline biosynthetic pathway and plays a central role in the regulation of this process in plants. To determine the evolutionary events that occurred in P5CS genes, partial sequences from four Neotropical trees were cloned and compared to those of other plant taxa. Molecular phylogenetic analysis indicated that P5CS duplication events have occurred several times following the emergence of flowering plants and at different frequencies throughout the evolution of monocots and dicots. Despite the high number of conserved residues in plant P5CS sequences, positive selection was observed at different regions of P5CS paralogous genes and also when dicots and monocots were contrasted.
authors.affiliation: Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Andreia Carina
authors.initials: AC
authors.lastname: Turchetto-Zolet
authors.forename: Marcia
authors.initials: M
authors.lastname: Margis-Pinheiro
authors.forename: Rogerio
authors.initials: R
authors.lastname: Margis
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009953:Ornithine-Oxo-Acid Transaminase / Q000235:genetics* / Q000378:metabolism*; D009997:Osmotic Pressure; D010802:Phylogeny; D010944:Plants / Q000145:classification / Q000201:enzymology* / Q000235:genetics*; D011392:Proline / Q000096:biosynthesis*; D017386:Sequence Homology, Amino Acid; D014197:Trees / Q000201:enzymology / Q000235:genetics; D014329:Tropical Climate
chemical_list: D017931:DNA Primers; D018744:DNA, Plant; D011392:Proline; D009953:Ornithine-Oxo-Acid Transaminase