title: γ-Aminobutyric acid (GABA) signalling in plants.
abstract: The role of γ-aminobutyric acid (GABA) as a signal in animals has been documented for over 60 years. In contrast, evidence that GABA is a signal in plants has only emerged in the last 15 years, and it was not until last year that a mechanism by which this could occur was identified-a plant 'GABA receptor' that inhibits anion passage through the aluminium-activated malate transporter family of proteins (ALMTs). ALMTs are multigenic, expressed in different organs and present on different membranes. We propose GABA regulation of ALMT activity could function as a signal that modulates plant growth, development, and stress response. In this review, we compare and contrast the plant 'GABA receptor' with mammalian GABAAreceptors in terms of their molecular identity, predicted topology, mode of action, and signalling roles. We also explore the implications of the discovery that GABA modulates anion flux in plants, its role in signal transduction for the regulation of plant physiology, and predict the possibility that there are other GABA interaction sites in the N termini of ALMT proteins through in silico evolutionary coupling analysis; we also explore the potential interactions between GABA and other signalling molecules.
authors.affiliation: Plant Transport and Signalling Lab, ARC Centre of Excellence in Plant Energy Biology and School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia.
authors.forename: Sunita A
authors.initials: SA
authors.lastname: Ramesh
authors.affiliation: Plant Transport and Signalling Lab, ARC Centre of Excellence in Plant Energy Biology and School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Tyerman
authors.affiliation: Plant Transport and Signalling Lab, ARC Centre of Excellence in Plant Energy Biology and School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Gilliham
authors.affiliation: Plant Transport and Signalling Lab, ARC Centre of Excellence in Plant Energy Biology and School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia. b.xu@adelaide.edu.au.
authors.forename: Bo
authors.identifier: 0000-0002-7583-2384
authors.initials: B
authors.lastname: Xu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D010944:Plants / Q000378:metabolism*; D011963:Receptors, GABA-A / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D002118:Calcium
keywords: Aluminium-activated malate transporters; Carbon–nitrogen balance; GABA metabolism; GABAA receptors; Pharmacology; Signalling; Stress response; Topology; γ-Aminobutyric acid