title: Rapid structural changes and acidification of guard cell vacuoles during stomatal closure require phosphatidylinositol 3,5-bisphosphate.
abstract: Rapid stomatal closure is essential for water conservation in plants and is thus critical for survival under water deficiency. To close stomata rapidly, guard cells reduce their volume by converting a large central vacuole into a highly convoluted structure. However, the molecular mechanisms underlying this change are poorly understood. In this study, we used pH-indicator dyes to demonstrate that vacuolar convolution is accompanied by acidification of the vacuole in fava bean (Vicia faba) guard cells during abscisic acid (ABA)-induced stomatal closure. Vacuolar acidification is necessary for the rapid stomatal closure induced by ABA, since a double mutant of the vacuolar H(+)-ATPase vha-a2 vha-a3 and vacuolar H(+)-PPase mutant vhp1 showed delayed stomatal closure. Furthermore, we provide evidence for the critical role of phosphatidylinositol 3,5-bisphosphate [PtdIns(3,5)P2] in changes in pH and morphology of the vacuole. Single and double Arabidopsis thaliana null mutants of phosphatidylinositol 3-phosphate 5-kinases (PI3P5Ks) exhibited slow stomatal closure upon ABA treatment compared with the wild type. Moreover, an inhibitor of PI3P5K reduced vacuolar acidification and convolution and delayed stomatal closure in response to ABA. Taken together, these results suggest that rapid ABA-induced stomatal closure requires PtdIns(3,5)P2, which is essential for vacuolar acidification and convolution.
authors.affiliation: POSTECH-UZH Cooperative Laboratory, Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Gwangbae
authors.initials: G
authors.lastname: Bak
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Yuree
authors.initials: Y
authors.lastname: Lee
authors.forename: Mariko
authors.initials: M
authors.lastname: Kato
authors.forename: Shoji
authors.initials: S
authors.lastname: Segami
authors.forename: Heven
authors.initials: H
authors.lastname: Sze
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Maeshima
authors.forename: Jae-Ung
authors.initials: JU
authors.lastname: Hwang
authors.forename: Youngsook
authors.initials: Y
authors.lastname: Lee
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000631:Aminopyridines / Q000494:pharmacology; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002087:Butyrates / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006575:Heterocyclic Compounds, 3-Ring / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D043564:Inorganic Pyrophosphatase / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D009154:Mutation; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology; D054046:Plant Stomata / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D031307:Vicia faba / Q000166:cytology / Q000235:genetics / Q000378:metabolism
chemical_list: C540576:6-amino-N-(3-(4-(4-morpholinyl)pyrido(3',2'-4,5)furo(3,2-d)pyrimidin-2-yl)phenyl)-3-pyridinecarboxamide; D000631:Aminopyridines; D029681:Arabidopsis Proteins; D002087:Butyrates; D006575:Heterocyclic Compounds, 3-Ring; D018129:Phosphatidylinositol Phosphates; D010937:Plant Growth Regulators; C106336:phosphatidylinositol 3,5-diphosphate; D049452:Green Fluorescent Proteins; D000040:Abscisic Acid; C547216:FAB1A protein, Arabidopsis; C547217:FAB1B protein, Arabidopsis; C586771:FAB1C protein, Arabidopsis; C586772:FAB1D protein, Arabidopsis; D017853:Phosphotransferases (Alcohol Group Acceptor); D025262:Vacuolar Proton-Translocating ATPases; D043564:Inorganic Pyrophosphatase