Mitogen-Activated Protein Kinase Is Involved in Abscisic Acid-Induced Antioxidant Defense and Acts Downstream of Reactive Oxygen Species Production in Leaves of Maize Plants

Abstract

The role of mitogen-activated protein kinase (MAPK) in abscisic acid (ABA)-induced antioxidant defense was investigated in leaves of maize (Zea mays) plants. Treatments with ABA or H 2 O 2 induced the activation of a 46-kD MAPK and enhanced the expression of the antioxidant genes CAT1, cAPX, and GR1 and the total activities of the antioxidant enzymes catalase, ascorbate peroxidase, glutathione reductase, and superoxide dismutase. Such enhancements were blocked by pretreatment with several MAPK kinase inhibitors and reactive oxygen species inhibitors or scavengers. Pretreatment with MAPK kinase inhibitors also substantially arrested the ABA-induced H 2 O 2 production after 2 h of ABA treatment, but did not affect the levels of H 2 O 2 within 1 h of ABA treatment. Pretreatment with several inhibitors of protein tyrosine phosphatase, which is believed to be a negative regulator of MAPK, only slightly prevented the ABA-induced H 2 O 2 production, but did not affect the ABA-induced MAPK activation and ABA-enhanced antioxidant defense systems. These results clearly suggest that MAPK but not protein tyrosine phosphatase is involved in the ABA-induced antioxidant defense, and a cross talk between H 2 O 2 production and MAPK activation plays a pivotal role in the ABA signaling. ABA-induced H 2 O 2 production activates MAPK, which in turn induces the expression and the activities of antioxidant enzymes. The activation of MAPK also enhances the H 2 O 2 production, forming a positive feedback loop.

Molecular cloning of a coiled-coil-nucleotide-binding-site-leucine-rich repeat gene from pearl millet and its expression pattern in response to the downy mildew pathogen

“…In maize, the PD98059 and U0126 MPK inhibitors were used to study the abscisic acid-induced expression of antioxidant genes CAT3, cAPX and GR1 mediated by MPK [46]. In the present study, the IP18296 resistant cultivar of pearl millet upon PD98059 or U0126 treatment showed inhibition of MPK activity and suppression of RGA RGPM 301 levels even after SA treatment.…”

Global plant-responding mechanisms to salt stress: physiological and molecular levels and implications in biotechnology

“…The involvement of ABA in antioxidant defense responses is that ABA induces antioxidant defense. During the ABA-induced antioxidant defense, H 2 O 2 , NO and MAPK are major components (Hu et al, 2005;Miller et al, 2010;Ye et al, 2011;Zhang et al, 2006Zhang et al, , 2007. Zhang et al (2012) reported that the zinc finger protein ZFP182 also mediated the ABA-induced antioxidant defense.…”

Cross-talk between calcium-calmodulin and nitric oxide in abscisic acid signaling in leaves of maize plants

“…Accumulating evidence indicates that ABAenhanced water stress tolerance is, at least in part, due to the induction of antioxidant defense systems [3][4][5][6]. Previous studies have shown that NADPH oxidase, hydrogen peroxide (H 2 O 2 ), nitric oxide (NO), calcium (Ca 2+ )-calmodulin (CaM), and mitogen-activated protein kinase (MAPK) are required for ABA-induced up-regulation in the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) and glutathione reductase (GR) in leaves of maize plants [7][8][9][10][11]. It has been shown that ABA-induced H 2 O 2 production mediates NO generation, which, in turn, activates MAPK and results in the up-regulation in the expression and the activities of antioxidant enzymes in ABA signaling [11].…”