title: Involvement of endogenous abscisic acid in methyl jasmonate-induced stomatal closure in Arabidopsis.
abstract: In this study, we examined the involvement of endogenous abscisic acid (ABA) in methyl jasmonate (MeJA)-induced stomatal closure using an inhibitor of ABA biosynthesis, fluridon (FLU), and an ABA-deficient Arabidopsis (Arabidopsis thaliana) mutant, aba2-2. We found that pretreatment with FLU inhibited MeJA-induced stomatal closure but not ABA-induced stomatal closure in wild-type plants. The aba2-2 mutation impaired MeJA-induced stomatal closure but not ABA-induced stomatal closure. We also investigated the effects of FLU and the aba2-2 mutation on cytosolic free calcium concentration ([Ca(2+)](cyt)) in guard cells using a Ca(2+)-reporter fluorescent protein, Yellow Cameleon 3.6. In wild-type guard cells, FLU inhibited MeJA-induced [Ca(2+)](cyt) elevation but not ABA-induced [Ca(2+)](cyt) elevation. The aba2-2 mutation did not affect ABA-elicited [Ca(2+)](cyt) elevation but suppressed MeJA-induced [Ca(2+)](cyt) elevation. We also tested the effects of the aba2-2 mutation and FLU on the expression of MeJA-inducible VEGETATIVE STORAGE PROTEIN1 (VSP1). In the aba2-2 mutant, MeJA did not induce VSP1 expression. In wild-type leaves, FLU inhibited MeJA-induced VSP1 expression. Pretreatment with ABA at 0.1 μm, which is not enough concentration to evoke ABA responses in the wild type, rescued the observed phenotypes of the aba2-2 mutant. Finally, we found that in wild-type leaves, MeJA stimulates the expression of 9-CIS-EPOXYCAROTENOID DIOXYGENASE3, which encodes a crucial enzyme in ABA biosynthesis. These results suggest that endogenous ABA could be involved in MeJA signal transduction and lead to stomatal closure in Arabidopsis guard cells.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Tsushima-Naka, Okayama 700-8530, Japan.
authors.forename: Mohammad Anowar
authors.initials: MA
authors.lastname: Hossain
authors.forename: Shintaro
authors.initials: S
authors.lastname: Munemasa
authors.forename: Misugi
authors.initials: M
authors.lastname: Uraji
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Izumi C
authors.initials: IC
authors.lastname: Mori
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Murata
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D000085:Acetates / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology*; D049308:Dioxygenases / Q000235:genetics* / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism; D006540:Herbicides / Q000494:pharmacology; D009154:Mutation; D054883:Oxylipins / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000378:metabolism* / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D054046:Plant Stomata / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D011728:Pyridones / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D000085:Acetates; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D006540:Herbicides; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011728:Pyridones; C013351:fluridone; D000040:Abscisic Acid; C072239:methyl jasmonate; D049308:Dioxygenases; C109043:9-cis-epoxy-carotenoid dioxygenase; C441479:VSP1 protein, Arabidopsis; D010450:Endopeptidases; D002118:Calcium