title: Release of extracellular purines from plant roots and effect on ion fluxes.
abstract: Extracellular purine nucleotides appear capable of regulating plant development, defence and stress responses by acting in part as agonists of plasma membrane calcium channels. Factors stimulating ATP release include wounding, osmotic stress and elicitors. Here we show that exogenous abscisic acid and L-glutamate can also cause ATP accumulation around Arabidopsis thaliana roots. Release of ADP from root epidermis would trigger ionotropic receptor-like activity in the plasma membrane, resulting in transient elevation of cytosolic free calcium. Root epidermal protoplasts (expressing aequorin as a cytosolic free calcium reporter) can support an extracellular ADP-induced cytosolic calcium elevation in the presence of an extracellular reductant. This confirms that ADP could elicit calcium-based responses distinct to those of ATP, which have been shown previously to involve production of extracellular reactive oxygen species.
authors: Department of Plant Sciences, University of Cambridge, Cambridge, UK.
authors: Adeeba
authors: A
authors: Dark
authors: Vadim
authors: V
authors: Demidchik
authors: Siân L
authors: SL
authors: Richards
authors: Sergey
authors: S
authors: Shabala
authors: Julia M
authors: JM
authors: Davies
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000244:Adenosine Diphosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling; D018698:Glutamic Acid / Q000494:pharmacology*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D015220:Calcium Channels; D018698:Glutamic Acid; D000244:Adenosine Diphosphate; D000040:Abscisic Acid; D000255:Adenosine Triphosphate; D002118:Calcium