Induction of protection against paraquat-induced oxidative damage by abscisic acid in maize leaves is mediated through mitogen-activated protein kinase.
Mitogen-activated protein kinase (MAPK) cascade has been shown to be important components in stress signal transduction pathway. In the present study, protection of maize seedlings (Zea mays L.) against paraquat-generated oxidative toxicity by abscisic acid (ABA), its association with MAPK and ZmMPK5, a candidate for MAPK were investigated. Treatment of maize leaves with exogenous ABA led to significant decreases in the content of malondialdehyde, the percentage of ion leakage and the level of protein oxidation (in terms of carbonyl groups) under paraquat (PQ) stress. However, such decreases were blocked by the pretreatment with two MAPK kinase inhibitors PD98059 and U0126. The damage caused by PQ was further aggravated by inhibitors. Two inhibitors also suppressed the total activities of the antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2). Besides, treatment with PQ stimulated the activation of a 46 kDa MAPK, which was identified as ZmMPK5 by in-gel kinase assay with immunoprecipitation. These results reveal that ABA-induced protection against PQ-generated oxidative damage is mediated through MAPK cascade in maize leaves, in which ZmMPK5, a candidate for MAPK, is demonstrated to be involved.
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Hai-Dong
HD
Ding
Xiao-Hua
XH
Zhang
Shu-Cheng
SC
Xu
Li-Li
LL
Sun
Ming-Yi
MY
Jiang
A-Ying
AY
Zhang
Yin-Gen
YG
Jin
D000040:Abscisic Acid / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism; D060387:Ascorbate Peroxidases; D002070:Butadienes / Q000494:pharmacology; D002374:Catalase / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology; D005980:Glutathione Reductase / Q000378:metabolism; D047468:Immunoprecipitation; D008315:Malondialdehyde / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D010269:Paraquat / Q000633:toxicity*; D010544:Peroxidases; D018515:Plant Leaves / Q000187:drug effects* / Q000378:metabolism*; D010940:Plant Proteins; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects* / Q000378:metabolism*
D000975:Antioxidants; D002070:Butadienes; D005419:Flavonoids; D009570:Nitriles; D010940:Plant Proteins; C113580:U 0126; D008315:Malondialdehyde; D000040:Abscisic Acid; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D020928:Mitogen-Activated Protein Kinases; C402117:ZmMPK5; D010269:Paraquat; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one