title: An ornithine δ-aminotransferase gene OsOAT confers drought and oxidative stress tolerance in rice.
abstract: Ornithine δ-aminotransferase (δ-OAT) is a pyridoxal-5'-phosphate-dependent enzyme that has been proposed to be involved in proline (Pro) and arginine (Arg) metabolism. However, the actual role of δ-OAT in abiotic responses in plants remains to be clarified. Here we characterized an ornithine δ-aminotransferase gene OsOAT that confers multi-stress tolerance in rice (Oryza sativa). We confirmed that OsOAT is a direct target of the stress-responsive NAC transcription factor SNAC2. OsOAT is responsive to multiple stresses and phytohormone treatments. Both ABA-dependent and ABA-independent pathways contributed to the drought-induced expression of OsOAT. Overexpression of the OsOAT gene in rice resulted in significantly enhanced drought and osmotic stress tolerance. Overexpression of OsOAT caused significantly increased δ-OAT activity and Pro accumulation under normal growth conditions. In addition, OsOAT-overexpressing plants showed significantly increased tolerance to oxidative stress. The glutathione (GSH) content and activity of reactive oxygen species (ROS)-scavenging enzymes, such as glutathione peroxidase, were also increased in OsOAT-overexpressing plants. We conclude that OsOAT is a target gene of SNAC2 and confers stress tolerance mainly through enhancing ROS-scavenging capacity and Pro pre-accumulation.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Jun
authors.initials: J
authors.lastname: You
authors.forename: Honghong
authors.initials: H
authors.lastname: Hu
authors.forename: Lizhong
authors.initials: L
authors.lastname: Xiong
mesh_terms: D055864:Droughts; D016166:Free Radical Scavengers / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D005978:Glutathione / Q000378:metabolism; D009953:Ornithine-Oxo-Acid Transaminase / Q000235:genetics* / Q000378:metabolism; D012275:Oryza / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D009997:Osmotic Pressure; D018384:Oxidative Stress; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011392:Proline / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological / Q000235:genetics*; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D010937:Plant Growth Regulators; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D011392:Proline; D009953:Ornithine-Oxo-Acid Transaminase; D005978:Glutathione