title: Analysis of the molecular evolutionary history of the ascorbate peroxidase gene family: inferences from the rice genome.
abstract: Ascorbate peroxidase (APx) is a class I peroxidase that catalyzes the conversion of H(2)O(2) to H(2)O and O(2) using ascorbate as the specific electron donor. This enzyme has a key function in scavenging reactive oxygen species (ROS) and the protection against toxic effects of ROS in higher plants, algae, and Euglena. Here we report the identification of an APx multigene family in rice and propose a molecular evolutionary relationship between the diverse APx isoforms. In rice, the APx gene family has eight members, which encode two cytosolic, two putative peroxisomal, and four chloroplastic isoforms, respectively. Phylogenetic analyses were conducted using all APx protein sequences available in the NCBI databases. The results indicate that the different APx isoforms arose by a complex evolutionary process involving several gene duplications. The structural organization of APx genes also reflects this process and provides evidence for a close relationship among proteins located in the same subcellular compartment. A molecular evolutionary pathway, in which cytosolic and peroxisomal isoforms diverged early from chloroplastic ones, is proposed.
authors.affiliation: Laboratório de Genética Molecular Vegetal, Departamento de Genética, UFRJ, 21944-970 Rio de Janeiro, Brasil.
authors.forename: Felipe Karam
authors.initials: FK
authors.lastname: Teixeira
authors.forename: Larissa
authors.initials: L
authors.lastname: Menezes-Benavente
authors.forename: Rogério
authors.initials: R
authors.lastname: Margis
authors.forename: Márcia
authors.initials: M
authors.lastname: Margis-Pinheiro
mesh_terms: D000595:Amino Acid Sequence; D060387:Ascorbate Peroxidases; D016000:Cluster Analysis; D019295:Computational Biology; D030561:Databases, Nucleic Acid; D019143:Evolution, Molecular; D020440:Gene Duplication; D018745:Genome, Plant; D007527:Isoenzymes / Q000235:genetics; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D012275:Oryza / Q000235:genetics*; D010544:Peroxidases / Q000235:genetics*; D010802:Phylogeny; D016415:Sequence Alignment
chemical_list: D007527:Isoenzymes; D010544:Peroxidases; D060387:Ascorbate Peroxidases