title: The cytosolic/nuclear HSC70 and HSP90 molecular chaperones are important for stomatal closure and modulate abscisic acid-dependent physiological responses in Arabidopsis.
abstract: Cytosolic/nuclear molecular chaperones of the heat shock protein families HSP90 and HSC70 are conserved and essential proteins in eukaryotes. These proteins have essentially been implicated in the innate immunity and abiotic stress tolerance in higher plants. Here, we demonstrate that both chaperones are recruited in Arabidopsis (Arabidopsis thaliana) for stomatal closure induced by several environmental signals. Plants overexpressing HSC70-1 or with reduced HSP90.2 activity are compromised in the dark-, CO(2)-, flagellin 22 peptide-, and abscisic acid (ABA)-induced stomatal closure. HSC70-1 and HSP90 proteins are needed to establish basal expression levels of several ABA-responsive genes, suggesting that these chaperones might also be involved in ABA signaling events. Plants overexpressing HSC70-1 or with reduced HSP90.2 activity are hypersensitive to ABA in seed germination assays, suggesting that several chaperone complexes with distinct substrates might tune tissue-specific responses to ABA and the other biotic and abiotic stimuli studied. This study demonstrates that the HSC70/HSP90 machinery is important for stomatal closure and serves essential functions in plants to integrate signals from their biotic and abiotic environments.
authors.affiliation: Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6191 Biolologie Végétale and Microbiologie Environnementale, F-13108 Saint-Paul-lez-Durance, France.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Clément
authors.forename: Nathalie
authors.initials: N
authors.lastname: Leonhardt
authors.forename: Marie-Jo
authors.initials: MJ
authors.lastname: Droillard
authors.forename: Ilja
authors.initials: I
authors.lastname: Reiter
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Montillet
authors.forename: Bernard
authors.initials: B
authors.lastname: Genty
authors.forename: Christiane
authors.initials: C
authors.lastname: Laurière
authors.forename: Laurent
authors.initials: L
authors.lastname: Nussaume
authors.forename: Laurent D
authors.initials: LD
authors.lastname: Noël
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D003624:Darkness; D003681:Dehydration; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D018525:Germination / Q000187:drug effects; D050883:HSC70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010455:Peptides / Q000494:pharmacology; D054046:Plant Stomata / Q000187:drug effects / Q000502:physiology*; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D050883:HSC70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D010455:Peptides; D000040:Abscisic Acid; D000251:Adenosine Triphosphatases