title: Arabidopsis PYR/PYL/RCAR receptors play a major role in quantitative regulation of stomatal aperture and transcriptional response to abscisic acid.
abstract: Abscisic acid (ABA) is a key hormone for plant growth, development, and stress adaptation. Perception of ABA through four types of receptors has been reported. We show here that impairment of ABA perception through the PYRABACTIN RESISTANCE1 (PYR1)/PYR1-LIKE (PYL)/REGULATORY COMPONENTS OF ABA RECEPTORS (RCAR) branch reduces vegetative growth and seed production and leads to a severe open stomata and ABA-insensitive phenotype, even though other branches for ABA perception remain functional. An Arabidopsis thaliana sextuple mutant impaired in six PYR/PYL receptors, namely PYR1, PYL1, PYL2, PYL4, PYL5, and PYL8, was able to germinate and grow even on 100 μM ABA. Whole-rosette stomatal conductance (Gst) measurements revealed that leaf transpiration in the sextuple pyr/pyl mutant was higher than in the ABA-deficient aba3-1 or ABA-insensitive snrk2.6 mutants. The gradually increasing Gst values of plants lacking three, four, five, and six PYR/PYLs indicate quantitative regulation of stomatal aperture by this family of receptors. The sextuple mutant lacked ABA-mediated activation of SnRK2s, and ABA-responsive gene expression was dramatically impaired as was reported in snrk2.2/2.3/2.6. In summary, these results show that ABA perception by PYR/PYLs plays a major role in regulation of seed germination and establishment, basal ABA signaling required for vegetative and reproductive growth, stomatal aperture, and transcriptional response to the hormone.
authors: Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, ES-46022 Valencia, Spain.
authors: Miguel
authors: M
authors: Gonzalez-Guzman
authors: Gaston A
authors: GA
authors: Pizzio
authors: Regina
authors: R
authors: Antoni
authors: Francisco
authors: F
authors: Vera-Sirera
authors: Ebe
authors: E
authors: Merilo
authors: George W
authors: GW
authors: Bassel
authors: Maria A
authors: MA
authors: Fernández
authors: Michael J
authors: MJ
authors: Holdsworth
authors: Miguel Angel
authors: MA
authors: Perez-Amador
authors: Hannes
authors: H
authors: Kollist
authors: Pedro L
authors: PL
authors: Rodriguez
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000502:physiology; D054046:Plant Stomata / Q000502:physiology*; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; C569327:PYL2 protein, Arabidopsis; C540976:AT4G17870 protein, Arabidopsis; C492978:SnRK2 protein, Arabidopsis; D000040:Abscisic Acid; D017346:Protein Serine-Threonine Kinases