Abstract
Salicylic acid (SA) induces stomatal closure sharing several components with abscisic acid (ABA) and methyl jasmonate (MeJA) signaling. We have previously shown that two guard cell-preferential mitogen-activated protein kinases (MAPKs), MPK9 and MPK12, positively regulate ABA signaling and MeJA signaling in Arabidopsis thaliana. In this study, we examined whether these two MAPKs are involved in SA-induced stomatal closure using genetic mutants and a pharmacological, MAPKK inhibitor. Salicylic acid induced stomatal closure in mpk9 and mpk12 single mutants but not in mpk9 mpk12 double mutants. The MAPKK inhibitor PD98059 inhibited SA-induced stomatal closure in wild-type plants. Salicylic acid induced extracellular reactive oxygen species (ROS) production, intracellular ROS accumulation, and cytosolic alkalization in the mpk9, mpk12, and mpk9 mpk12 mutants. Moreover, SA-activated S-type anion channels in guard cells of wild-type plants but not in guard cells of mpk9 mpk12 double mutants. These results imply that MPK9 and MPK12 are positive regulators of SA signaling in Arabidopsis guard cells.
Keywords:
S-type anion channel in guard cells; cytosolic alkalization; mitogen-activated protein kinase; reactive oxygen species; salicylic acid.
MeSH terms
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Abscisic Acid / metabolism
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Abscisic Acid / pharmacology
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Acetates / metabolism
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Acetates / pharmacology
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Arabidopsis / drug effects*
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Arabidopsis / genetics
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Arabidopsis / metabolism
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism
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Cyclopentanes / metabolism
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Cyclopentanes / pharmacology
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Flavonoids / pharmacology
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Gene Expression Regulation, Plant*
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Hydrogen-Ion Concentration
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Membrane Potentials / drug effects
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Mitogen-Activated Protein Kinases / genetics
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Mitogen-Activated Protein Kinases / metabolism
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Mutation
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Oxylipins / metabolism
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Oxylipins / pharmacology
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Plant Growth Regulators / metabolism
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Plant Growth Regulators / pharmacology
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Plant Stomata / drug effects*
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Plant Stomata / genetics
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Plant Stomata / metabolism
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Protein Kinase Inhibitors / pharmacology
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Reactive Oxygen Species / agonists
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Reactive Oxygen Species / metabolism
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Salicylic Acid / metabolism
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Salicylic Acid / pharmacology*
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Signal Transduction
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Voltage-Dependent Anion Channels / genetics
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Voltage-Dependent Anion Channels / metabolism
Substances
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Acetates
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Arabidopsis Proteins
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Cyclopentanes
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Flavonoids
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Oxylipins
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Plant Growth Regulators
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Protein Kinase Inhibitors
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Reactive Oxygen Species
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Voltage-Dependent Anion Channels
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Abscisic Acid
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methyl jasmonate
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MPK12 protein, Arabidopsis
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MPK9 protein, Arabidopsis
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Mitogen-Activated Protein Kinases
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Salicylic Acid
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2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one