title: Cross-talk between calcium-calmodulin and nitric oxide in abscisic acid signaling in leaves of maize plants.
abstract: Using pharmacological and biochemical approaches, the signaling pathways between hydrogen peroxide (H(2)O(2)), calcium (Ca(2+))-calmodulin (CaM), and nitric oxide (NO) in abscisic acid (ABA)-induced antioxidant defense were investigated in leaves of maize (Zea mays L.) plants. Treatments with ABA, H(2)O(2), and CaCl(2) induced increases in the generation of NO in maize mesophyll cells and the activity of nitric oxide synthase (NOS) in the cytosolic and microsomal fractions of maize leaves. However, such increases were blocked by the pretreatments with Ca(2+) inhibitors and CaM antagonists. Meanwhile, pretreatments with two NOS inhibitors also suppressed the Ca(2+)-induced increase in the production of NO. On the other hand, treatments with ABA and the NO donor sodium nitroprusside (SNP) also led to increases in the concentration of cytosolic Ca(2+) in protoplasts of mesophyll cells and in the expression of calmodulin 1 (CaM1) gene and the contents of CaM in leaves of maize plants, and the increases induced by ABA were reduced by the pretreatments with a NO scavenger and a NOS inhibitor. Moreover, SNP-induced increases in the expression of the antioxidant genes superoxide dismutase 4 (SOD4), cytosolic ascorbate peroxidase (cAPX), and glutathione reductase 1 (GR1) and the activities of the chloroplastic and cytosolic antioxidant enzymes were arrested by the pretreatments with Ca(2+) inhibitors and CaM antagonists. Our results suggest that Ca(2+)-CaM functions both upstream and downstream of NO production, which is mainly from NOS, in ABA- and H(2)O(2)-induced antioxidant defense in leaves of maize plants.
authors: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors: Jianrong
authors: J
authors: Sang
authors: Aying
authors: A
authors: Zhang
authors: Fan
authors: F
authors: Lin
authors: Mingpu
authors: M
authors: Tan
authors: Mingyi
authors: M
authors: Jiang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D002147:Calmodulin / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D003313:Zea mays / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
chemical_list: D002147:Calmodulin; D010937:Plant Growth Regulators; D010940:Plant Proteins; D009599:Nitroprusside; D009569:Nitric Oxide; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase; D002122:Calcium Chloride; D002118:Calcium