title: Glutamate functions in stomatal closure in Arabidopsis and fava bean.
abstract: Guard cells are indispensable for higher plants because they control gas exchange and water balance to maintain photosynthetic activity. The signaling processes that govern their movement are controlled by several factors, such as abscisic acid (ABA), blue light, pathogen-associated molecular patterns (PAMPs), and carbon dioxide. Herein, we demonstrated that the amino acid glutamate (Glu), a well-known mammalian neurotransmitter, functions as a novel signaling molecule in stomatal closure in both Arabidopsis and fava bean (Vicia faba L.). Pharmacological and electrophysiological analyses provided important clues for the participation of Glu-receptors, Ca(2+), and protein phosphorylation during the signaling process. Genetic analyses using Arabidopsis ABA-deficient (aba2-1) and ABA-insensitive (abi1-1 and abi2-1) mutants showed that ABA is not required for Glu signaling. However, loss-of-function of the Arabidopsis gene encoding Slow Anion Channel-Associated 1 (SLAC1) and Calcium-Dependent Protein Kinase 6 (CPK6) impaired the Glu response. Moreover, T-DNA knockout mutations of the Arabidopsis Glu receptor-like gene (GLR), GLR3.5, lost their sensitivity to Glu-dependent stomatal closure. Our results strongly support functional Glu-signaling in stomatal closure and the crucial roles of GLRs in this signaling process.
authors.affiliation: Laboratory of Horticultural Science, Faculty of Agriculture, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima, Kagoshima, 890-0065, Japan. ryoshida@agri.kagoshima-u.ac.jp.
authors.forename: Riichiro
authors.initials: R
authors.lastname: Yoshida
authors.affiliation: Institute of Plant Sciences and Resources, Okayama University, 2-20-1, Chuo, Kurashiki, 710-0046, Japan.
authors.forename: Izumi C
authors.initials: IC
authors.lastname: Mori
authors.affiliation: Laboratory of Horticultural Science, Faculty of Agriculture, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima, Kagoshima, 890-0065, Japan.
authors.forename: Nobuto
authors.initials: N
authors.lastname: Kamizono
authors.affiliation: Laboratory of Horticultural Science, Faculty of Agriculture, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima, Kagoshima, 890-0065, Japan.
authors.forename: Yudai
authors.initials: Y
authors.lastname: Shichiri
authors.affiliation: Laboratory of Horticultural Science, Faculty of Agriculture, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima, Kagoshima, 890-0065, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Shimatani
authors.affiliation: Laboratory of Horticultural Science, Faculty of Agriculture, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima, Kagoshima, 890-0065, Japan.
authors.forename: Fumika
authors.initials: F
authors.lastname: Miyata
authors.affiliation: Laboratory of Horticultural Science, Faculty of Agriculture, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima, Kagoshima, 890-0065, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Honda
authors.affiliation: Laboratory of Horticultural Science, Faculty of Agriculture, Kagoshima University, 1-21-24 Kohrimoto, Kagoshima, Kagoshima, 890-0065, Japan.
authors.forename: Sumio
authors.initials: S
authors.lastname: Iwai
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D018698:Glutamic Acid / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D054046:Plant Stomata / Q000502:physiology*; D017470:Receptors, Glutamate / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D031307:Vicia faba / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D017470:Receptors, Glutamate; D018698:Glutamic Acid
keywords: Arabidopis thaliana; Glutamate; Glutamate receptor; Signal transduction; Stomatal closure; Vicia faba