An ornithine ¦Ä-aminotransferase gene OsOAT confers drought and oxidative stress tolerance in rice

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• 作者：Jun You ; Honghong Hu ; Lizhong Xiong ; ^{lizhongx@mail.hzau.edu.cn} ; ^{xionglz322@yahoo.com.cn}
• 关键词：Oryza ; Abiotic stress ; Proline ; Ornithine aminotransferase
• 刊名：Plant Science
• 出版年：2012
• 出版时间：December, 2012
• 年：2012
• 卷：197
• 期：Complete
• 页码：59-69
• 全文大小：1904 K

文摘

Ornithine ¦Ä-aminotransferase (¦Ä-OAT) is a pyridoxal-5¡ä-phosphate-dependent enzyme that has been proposed to be involved in proline (Pro) and arginine (Arg) metabolism. However, the actual role of ¦Ä-OAT in abiotic responses in plants remains to be clarified. Here we characterized an ornithine ¦Ä-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 ¦Ä-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.