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.

Recent Advances in Calcium/Calmodulin-Mediated Signaling with an Emphasis on Plant-Microbe Interactions

“…Tobacco (Nicotiana tabacum) CCaMK was indicated to play a role in controlling the development of anther (Poovaiah et al, 1999), and pea (Pisum sativum) CCaMK was up-regulated in roots in response to low temperature and salt treatment (Pandey et al, 2002). Recent results showed that CCaMK from maize (Zea mays; ZmCCaMK) and rice (OsCCaMK) both play important roles in abscisic acid-induced antioxidant protection (Ma et al, 2012;Shi et al, 2012). Together, these results suggest that CCaMK acts as a multifunctional regulatory protein in plants.…”

Phosphorylation of a NAC Transcription Factor by a Calcium/Calmodulin-Dependent Protein Kinase Regulates Abscisic Acid-Induced Antioxidant Defense in Maize

“…Recently, a growing body of evidence reveals additional functions of CCaMK, such as response to ABA signaling and stress tolerance in wheat, maize, and rice Shi et al, 2012;Yang et al, 2011a). Hence, it is getting increasingly important to identify the downstream targets of CCaMK in order to understand the physiological role of CCaMK in different biological processes.…”

“…For the oxidative damage analysis, 4-week-old seedlings were treated with 20% PEG for 12 h. The content of MDA and the percentage of electrolyte leakage were determined as described by Shi et al (2012).…”

“…However, CCaMK is highly expressed outside of roots, indicating other roles besides the regulation of symbiosis. CCaMK has been shown to be involved in ABA signaling during abiotic stress response (Yang et al, 2011a) and ABA-induced antioxidant defense Shi et al, 2012). ABA-induced H 2 O 2 production activates CCaMK, which in turn induces antioxidant defense system by a largely unknown mechanism.…”

Decrypting Calcium Signaling in Plants: The Kinase Way

“…Lately, OsDMI3 has been found to be involved in ABA signaling in rice, where ABA treatment induced the expression of OsDMI3 and OsMPK1 as well as the activities of OsDMI3 is increased. It was also found that OsDMI3 functions upstream to OsMPK1 in regulating the activities of antioxidant enzymes and the production of H 2 O 2 in rice (Shi et al 2012(Shi et al , 2014. In maize, ZmCCaMK was identifi ed to be essential for ABAinduced antioxidant defense ( Ma et al 2012a ).…”