title: Calcium and ZmCCaMK are involved in brassinosteroid-induced antioxidant defense in maize leaves.
abstract: Brassinosteroids (BRs) have been shown to enhance stress tolerance by inducing antioxidant defense systems. However, the mechanisms of BR-induced antioxidant defense in plants remain to be determined. In this study, the role of calcium (Ca(2+)) and maize calcium/calmodulin-dependent protein kinase (CCaMK), ZmCCaMK, in BR-induced antioxidant defense, and the relationship between ZmCCaMK and Ca(2+) in BR signaling were investigated. BR treatment led to a significant increase in cytosolic Ca(2+) concentration in protoplasts from maize mesophyll, and Ca(2+) was shown to be required for BR-induced antioxidant defense. Treatment with BR induced increases in gene expression and enzyme activity of ZmCCaMK in maize leaves. Transient overexpression and silencing of ZmCCaMK in maize protoplasts demonstrated that ZmCCaMK was required for BR-induced antioxidant defense. The requirement for CCaMK was further investigated using a loss-of-function mutant of OsCCaMK, the orthologous gene of ZmCCaMK in rice. Consistent with the findings in maize, BR treatment could not induce antioxidant defense in the rice OsCCAMK mutant. Furthermore, Ca(2+) was required for BR-induced gene expression and activation of ZmCCaMK, while ZmCCaMK was shown to enhance the BR-induced increase in cytosolic Ca(2+) concentration. Moreover, our results also showed that ZmCCaMK and H2O2 influenced each other. These results indicate that Ca(2+) works together with ZmCCaMK in BR-induced antioxidant defense, and there are two positive feedback loops between Ca(2+) or H2O2 and ZmCCaMK in BR signaling in maize.
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China These authors contributed equally to this work.
authors: Jingwei
authors: J
authors: Yan
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China These authors contributed equally to this work.
authors: Li
authors: L
authors: Guan
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors: Yue
authors: Y
authors: Sun
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors: Yuan
authors: Y
authors: Zhu
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors: Lei
authors: L
authors: Liu
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors: Rui
authors: R
authors: Lu
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China National Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors: Mingyi
authors: M
authors: Jiang
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors: Mingpu
authors: M
authors: Tan
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China ayzhang@njau.edu.
authors: Aying
authors: A
authors: Zhang
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000378:metabolism; D060406:Brassinosteroids / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D065096:Calcium Chelating Agents / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011523:Protoplasts / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D003313:Zea mays / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics
chemical_list: D000975:Antioxidants; D060406:Brassinosteroids; D002121:Calcium Channel Blockers; D065096:Calcium Chelating Agents; D010940:Plant Proteins; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium
keywords: Antioxidant defense; Brassinosteroid; Calcium; Calcium/calmodulin-dependent protein kinase; H2O2; Maize