Nitric oxide induced by hydrogen peroxide mediates abscisic acid-induced activation of the mitogen-activated protein kinase cascade involved in antioxidant defense in maize leaves.
* The role of nitric oxide (NO) and the relationship between NO, hydrogen peroxide (H(2)O(2)) and mitogen-activated protein kinase (MAPK) in abscisic acid (ABA)-induced antioxidant defense in leaves of maize (Zea mays) plants were investigated. * Both ABA and H(2)O(2) induced increases in the generation of NO in mesophyll cells of maize leaves, and H(2)O(2) was required for the ABA-induced generation of NO. Pretreatment with NO scavenger and nitric oxide synthase (NOS) inhibitor substantially reduced the ABA-induced production of NO, and partly blocked the activation of a 46 kDa MAPK and the expression and the activities of several antioxidant enzymes induced by ABA. Treatment with the NO donor sodium nitroprusside (SNP) also induced the activation of the MAPK, and enhanced the antioxidant defense systems. * Conversely, SNP treatment did not induce the production of H(2)O(2), and pretreatments with NO scavenger and NOS inhibitor did not affect ABA-induced H(2)O(2) production. * Our results suggest that ABA-induced H(2)O(2) production mediates NO generation, which, in turn, activates MAPK and results in the upregulation in the expression and the activities of antioxidant enzymes in ABA signaling.
Zhang
Aying
A
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
Jiang
Mingyi
M
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
Zhang
Jianhua
J
Department of Biology, Hong Kong Baptist University, Hong Kong, People's Republic of China.
Ding
Haidong
H
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
Xu
Shucheng
S
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
Hu
Xiuli
X
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
Tan
Mingpu
M
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.
D000040:Abscisic Acid / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism*; D004789:Enzyme Activation; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D018613:Microscopy, Confocal; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000187:drug effects / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds; D003313:Zea mays / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*
D000975:Antioxidants; D010940:Plant Proteins; D018749:RNA, Plant; D009569:Nitric Oxide; D000040:Abscisic Acid; D006861:Hydrogen Peroxide; D020928:Mitogen-Activated Protein Kinases