Abstract:

Using pharmacological and biochemical approaches, the role of protein phosphorylation and the interrelationship between water stress-enhanced kinase activity, antioxidant enzyme activity, hydrogen peroxide(H₂O₂) accumulation and endogenous abscisic acid in maize (Zea mays L.) leaves were investigated. Water-stress upregulated the activities of total protein phosphorylation and Ca²⁺-dependent protein kinase, and the upregulation was blocked in abscisic acid-deficient vp5 mutant. Furthermore, pretreatments with a nicotinamide adenine dinucleotide phosphate oxidase inhibitor and a scavenger of H₂O₂ significantly reduced the increased activities of total protein kinase and Ca²⁺-dependent protein kinase in maize leaves exposed to water stress. Pretreatments with different protein kinase inhibitors also reduced the water stress-induced H₂O₂ production and the water stress-enhanced activities of antioxidant enzymes such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase. The data suggest that protein phosphorylation and H2O2 generation are required for water stress-induced antioxidant defense in maize leaves and that crosstalk between protein phosphorylation and H2O2 generation may occur.
 

Xu S, Ding H, Su F, Zhang A, Jiang M (2009).Involvement of protein phosphorylation in water stress-induced antioxidant defense in maize leaves. J. Integr. Plant Biol. 51(7), 654-662

Key words: abscisic acid, antioxidant defense, hydrogen peroxide, protein phosphorylation, water stress.