title: Calcium- and potassium-permeable plasma membrane transporters are activated by copper in Arabidopsis root tips: linking copper transport with cytosolic hydroxyl radical production.
abstract: Transition metals such as copper can interact with ascorbate or hydrogen peroxide to form highly reactive hydroxyl radicals (OH(•) ), with numerous implications to membrane transport activity and cell metabolism. So far, such interaction was described for extracellular (apoplastic) space but not cytosol. Here, a range of advanced electrophysiological and imaging techniques were applied to Arabidopsis thaliana plants differing in their copper-transport activity: Col-0, high-affinity copper transporter COPT1-overexpressing (C1(OE) ) seedlings, and T-DNA COPT1 insertion mutant (copt1). Low Cu concentrations (10 µm) stimulated a dose-dependent Gd(3+) and verapamil sensitive net Ca(2+) influx in the root apex but not in mature zone. C1(OE) also showed a fivefold higher Cu-induced K(+) efflux at the root tip level compared with Col-0, and a reduction in basal peroxide accumulation at the root tip after copper exposure. Copper caused membrane disruptions of the root apex in C1(OE) seedlings but not in copt1 plants; this damage was prevented by pretreatment with Gd(3+) . Our results suggest that copper transport into cytosol in root apex results in hydroxyl radical generation at the cytosolic side, with a consequent regulation of plasma membrane OH(•) -sensitive Ca(2+) and K(+) transport systems.
authors.affiliation: Fisiología Vegetal, Facultad de Biociencias, Universidad Autónoma de Barcelona, Bellaterra E-08193, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Rodrigo-Moreno
authors.forename: Nuria
authors.initials: N
authors.lastname: Andrés-Colás
authors.forename: Charlotte
authors.initials: C
authors.lastname: Poschenrieder
authors.forename: Benet
authors.initials: B
authors.lastname: Gunsé
authors.forename: Lola
authors.initials: L
authors.lastname: Peñarrubia
authors.forename: Sergey
authors.initials: S
authors.lastname: Shabala
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D000079923:Copper Transporter 1; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D055786:Gene Knockout Techniques; D006706:Homeostasis; D017665:Hydroxyl Radical / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018519:Meristem / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D016254:Mutagenesis, Insertional; D018384:Oxidative Stress; D010545:Peroxides / Q000032:analysis; D010641:Phenotype; D019441:Plant Epidermis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D036226:Seedlings / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; C097086:COPT1 protein, Arabidopsis; D000079923:Copper Transporter 1; D026901:Membrane Transport Proteins; D010545:Peroxides; D017665:Hydroxyl Radical; D003300:Copper; D014700:Verapamil; D011188:Potassium; D002118:Calcium