title: GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters.
abstract: The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms.
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.
authors.forename: Sunita A
authors.initials: SA
authors.lastname: Ramesh
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Tyerman
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.
authors.forename: Bo
authors.initials: B
authors.lastname: Xu
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.|School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia.
authors.forename: Jayakumar
authors.initials: J
authors.lastname: Bose
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.
authors.forename: Satwinder
authors.initials: S
authors.lastname: Kaur
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Conn
authors.affiliation: Gulbenkian Institute of Science, Oeiras P-2780-156, Portugal.|Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815, USA.
authors.forename: Patricia
authors.initials: P
authors.lastname: Domingos
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.
authors.forename: Sana
authors.initials: S
authors.lastname: Ullah
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Wege
authors.affiliation: School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Shabala
authors.affiliation: Gulbenkian Institute of Science, Oeiras P-2780-156, Portugal.|Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815, USA.
authors.forename: José A
authors.initials: JA
authors.lastname: Feijó
authors.affiliation: CSIRO Plant Industry, GPO Box 1600, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Ryan
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, South Australia 5064, Australia.
authors.forename: Matthew
authors.identifier: http://orcid.org/0000-0003-0666-3078
authors.initials: M
authors.lastname: Gilliham
mesh_terms: D000138:Acidosis; D000535:Aluminum / Q000378:metabolism; D020816:Amino Acid Motifs; D000818:Animals; D017360:Arabidopsis; D001640:Bicuculline / Q000494:pharmacology; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D001467:Hordeum; D008564:Membrane Potentials / Q000235:genetics; D018613:Microscopy, Confocal; D009118:Muscimol / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D009865:Oocytes; D027361:Organic Anion Transporters / Q000235:genetics* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D053205:Pollen Tube / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological / Q000235:genetics*; D014026:Nicotiana; D014908:Triticum; D027843:Vitis; D014982:Xenopus laevis; D005680:gamma-Aminobutyric Acid / Q000187:drug effects / Q000378:metabolism*
chemical_list: D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D027361:Organic Anion Transporters; D010940:Plant Proteins; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D000535:Aluminum; D001640:Bicuculline