title: G protein regulation of ion channels and abscisic acid signaling in Arabidopsis guard cells.
abstract: The phytohormone abscisic acid (ABA) promotes plant water conservation by decreasing the apertures of stomatal pores in the epidermis through which water loss occurs. We found that Arabidopsis thaliana plants harboring transferred DNA insertional mutations in the sole prototypical heterotrimeric GTP-binding (G) protein alpha subunit gene, GPA1, lack both ABA inhibition of guard cell inward K(+) channels and pH-independent ABA activation of anion channels. Stomatal opening in gpa1 plants is insensitive to inhibition by ABA, and the rate of water loss from gpa1 mutants is greater than that from wild-type plants. Manipulation of G protein status in guard cells may provide a mechanism for controlling plant water balance.
authors.affiliation: Biology Department, Pennsylvania State University, 208 Mueller Laboratory, University Park, PA 16802-5301, USA.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Ullah
authors.forename: A M
authors.initials: AM
authors.lastname: Jones
authors.forename: S M
authors.initials: SM
authors.lastname: Assmann
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology*; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins; D044385:GTP-Binding Protein alpha Subunits; D017343:Genes, Plant; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D009154:Mutation; D018408:Patch-Clamp Techniques; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying; D021122:Protein Subunits; D015398:Signal Transduction; D014867:Water / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C429765:GPA1 protein, Arabidopsis; D044385:GTP-Binding Protein alpha Subunits; D007473:Ion Channels; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D021122:Protein Subunits; D014867:Water; D000040:Abscisic Acid; D020962:Heterotrimeric GTP-Binding Proteins; D011188:Potassium