title: OsDMI3 is a novel component of abscisic acid signaling in the induction of antioxidant defense in leaves of rice.
abstract: Ca(2+) and calmodulin (CaM) have been shown to play an important role in abscisic acid (ABA)-induced antioxidant defense. However, it is unknown whether Ca(2+)/CaM-dependent protein kinase (CCaMK) is involved in the process. In the present study, the role of rice CCaMK, OsDMI3, in ABA-induced antioxidant defense was investigated in leaves of rice (Oryza sativa) plants. Treatments with ABA, H(2)O(2), and polyethylene glycol (PEG) induced the expression of OsDMI3 and the activity of OsDMI3, and H(2)O(2) is required for the ABA-induced increases in the expression and the activity of OsDMI3 under water stress. Subcellular localization analysis showed that OsDMI3 is located in the nucleus, the cytoplasm, and the plasma membrane. The analysis of the transient expression of OsDMI3 in rice protoplasts and the RNA interference (RNAi) silencing of OsDMI3 in rice protoplasts showed that OsDMI3 is required for ABA-induced increases in the expression and the activities of superoxide dismutase (SOD) and catalase (CAT). Further, the oxidative damage induced by higher concentrations of PEG and H(2)O(2) was aggravated in the mutant of OsDMI3. Moreover, the analysis of the RNAi silencing of OsDMI3 in protoplasts and the mutant of OsDMI3 showed that higher levels of H(2)O(2) accumulation require OsDMI3 activation in ABA signaling, but the initial H(2)O(2) production induced by ABA is not dependent on the activation of OsDMI3 in leaves of rice plants. Our data reveal that OsDMI3 is an important component in ABA-induced antioxidant defense in rice.
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095,  China.
authors.forename: Ben
authors.initials: B
authors.lastname: Shi
authors.forename: Lan
authors.initials: L
authors.lastname: Ni
authors.forename: Aying
authors.initials: A
authors.lastname: Zhang
authors.forename: Jianmei
authors.initials: J
authors.lastname: Cao
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Tingting
authors.initials: T
authors.lastname: Qin
authors.forename: Mingpu
authors.initials: M
authors.lastname: Tan
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhang
authors.forename: Mingyi
authors.initials: M
authors.lastname: Jiang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000975:Antioxidants / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D012275:Oryza / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D018515:Plant Leaves / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D011092:Polyethylene Glycols / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D011523:Protoplasts / Q000166:cytology / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D014867:Water / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002147:Calmodulin; D014867:Water; D011092:Polyethylene Glycols; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium