title: The maize alternative oxidase 1a (Aox1a) gene is regulated by signals related to oxidative stress.
abstract: We isolated and characterized the expression of Aox1a, a member of the maize alternative oxidase (Aox) small multigene family. Aox1a consists of four exons interrupted by three introns and its promoter harbors diverse stress-specific putative regulatory motifs pointing to complex regulation and response to multiple signals. Responses of Aox1a to such signals were examined and compared with those of maize glutathione S-transferase I (GstI), a typical oxidative stress inducible gene. Potassium cyanide (KCN) and hydrogen peroxide (H2O2) induced a rapid increase of the Aox1a and GstI transcripts, which was persisted in prolonged treatment at high H2O2 concentration only for Aox1a. High concentration of salicylic acid (SA) and salicyl hydroxamic acid (SHAM) induced Aox1a mRNA only after prolonged exposure, while GstI displayed an early strong induction, which declined thereafter. Nitric oxide (NO) induced a high increase of Aox1a after prolonged exposure at high concentration, while GstI displayed a weak response. Our results show that multiple signaling pathways, involved in stress responses, also participate and differentially regulate Aox1a and GstI in maize. A ROS-depended signaling event may be involved, suggesting an essential role of Aox1a under oxidative stress in maize.
authors.affiliation: Institute of Agrobiotechnology, Center for Research and Technology Hellas, Thermi, Greece. alexios@certh.gr
authors.forename: Alexios N
authors.initials: AN
authors.lastname: Polidoros
authors.forename: Photini V
authors.initials: PV
authors.lastname: Mylona
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Pasentsis
authors.forename: John G
authors.initials: JG
authors.lastname: Scandalios
authors.forename: Athanasios S
authors.initials: AS
authors.lastname: Tsaftaris
mesh_terms: D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007438:Introns; D024101:Mitochondrial Proteins; D008954:Models, Biological; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000096:biosynthesis* / Q000235:genetics*; D010940:Plant Proteins; D011190:Potassium Cyanide / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D017382:Reactive Oxygen Species; D012457:Salicylamides / Q000494:pharmacology; D020156:Salicylic Acid / Q000494:pharmacology; D015398:Signal Transduction; D003313:Zea mays / Q000235:genetics*; D000099188:Alternative Oxidase
chemical_list: D006861:Hydrogen Peroxide; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D011190:Potassium Cyanide; D017382:Reactive Oxygen Species; D012457:Salicylamides; D020156:Salicylic Acid; D000099188:Alternative Oxidase; C005703:salicylhydroxamic acid