Calcium-calmodulin is required for abscisic acid-induced antioxidant defense and functions both upstream and downstream of H2O2 production in leaves of maize (Zea mays) plants.
* Using pharmacological and biochemical approaches, the role of calmodulin (CaM) and the relationship between CaM and hydrogen peroxide (H(2)O(2)) in abscisic acid (ABA)-induced antioxidant defense in leaves of maize (Zea mays) plants were investigated. * Treatment with ABA or H(2)O(2) led to significant increases in the concentration of cytosolic Ca(2+) in the protoplasts of mesophyll cells and in the expression of the calmodulin 1 (CaM1) gene and the content of CaM in leaves of maize plants, and enhanced 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. The up-regulation of the antioxidant enzymes was almost completely blocked by pretreatments with two CaM antagonists. * Pretreatments with CaM antagonists almost completely inhibited ABA-induced H(2)O(2) production throughout ABA treatment, but pretreatment with an inhibitor or scavenger of reactive oxygen species (ROS) did not affect the initial increase in the contents of CaM induced by ABA. * Our results suggest that Ca(2+)-CaM is involved in ABA-induced antioxidant defense, and that cross-talk between Ca(2+)-CaM and H(2)O(2) plays a pivotal role in ABA signaling.
Hu
Xiuli
X
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Jiang
Mingyi
M
Zhang
Jianhua
J
Zhang
Aying
A
Lin
Fan
F
Tan
Mingpu
M
D000040:Abscisic Acid / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005980:Glutathione Reductase / Q000235:genetics / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011523:Protoplasts / Q000187:drug effects / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000494:pharmacology; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects / Q000378:metabolism*
D000975:Antioxidants; D002147:Calmodulin; D010937:Plant Growth Regulators; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D002118:Calcium