title: Functional analysis reveals effects of tobacco alternative oxidase gene (NtAOX1a) on regulation of defence responses against abiotic and biotic stresses.
abstract: Mitochondrial AOX (alternative oxidase) is the terminal oxidase of the CN (cyanide)-resistant alternative respiratory pathway in plants. To investigate the role of the tobacco AOX gene (NtAOX1a) (where Nt is Nicotiana tabacum) under deleterious conditions which could induce ROS (reactive oxygen species) accumulation, we generated and characterized a number of independent transgenic tobacco (N. tabacum) lines with altered NtAOX1a gene expression and AP (alternative pathway) capacity. AOX efficiently inhibited the production of low-temperature-induced H2O2 and might be a major enzyme for scavenging H2O2 at low temperature. Furthermore, NtAOX1a may act as a regulator of KCN-induced resistance to TMV (tobacco mosaic virus) through the regulation of H2O2. Notably, a moderate accumulation of H2O2 under the control of NtAOX1a was crucial in viral resistance. Analysis of seed germination indicated an important role for NtAOX1a in germination under H2O2-induced oxidative stress when the CP (cytochrome pathway) was inhibited. These results demonstrate that NtAOX1a is necessary for plants to survive low temperature, pathogen attack and oxidative stress by scavenging ROS under these adverse conditions when the CP is restricted.
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Dongmei
authors.initials: D
authors.lastname: Xi
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Dongfang
authors.initials: D
authors.lastname: Zhu
authors.forename: Xingqi
authors.initials: X
authors.lastname: Guo
mesh_terms: D016166:Free Radical Scavengers / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D007113:Immunity, Innate / Q000187:drug effects / Q000502:physiology*; D024101:Mitochondrial Proteins; D016877:Oxidants / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics; D011190:Potassium Cyanide / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology*; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics; D014027:Tobacco Mosaic Virus / Q000235:genetics; D000099188:Alternative Oxidase
chemical_list: D016166:Free Radical Scavengers; D006861:Hydrogen Peroxide; D024101:Mitochondrial Proteins; D016877:Oxidants; D010088:Oxidoreductases; D010940:Plant Proteins; D011190:Potassium Cyanide; D017382:Reactive Oxygen Species; D000099188:Alternative Oxidase