title: Choline but not its derivative betaine blocks slow vacuolar channels in the halophyte Chenopodium quinoa: implications for salinity stress responses.
abstract: Activity of tonoplast slow vacuolar (SV, or TPC1) channels has to be under a tight control, to avoid undesirable leak of cations stored in the vacuole. This is particularly important for salt-grown plants, to ensure efficient vacuolar Na(+) sequestration. In this study we show that choline, a cationic precursor of glycine betaine, efficiently blocks SV channels in leaf and root vacuoles of the two chenopods, Chenopodium quinoa (halophyte) and Beta vulgaris (glycophyte). At the same time, betaine and proline, two major cytosolic organic osmolytes, have no significant effect on SV channel activity. Physiological implications of these findings are discussed.
authors.affiliation: Centro de Investigaciones Biomédicas, Universidad de Colima, Mexico. Electronic address: pottosin@ucol.mx.
authors.forename: Igor
authors.initials: I
authors.lastname: Pottosin
authors.affiliation: Centro de Investigaciones Biomédicas, Universidad de Colima, Mexico; School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas 7001, Australia.
authors.forename: Edgar
authors.initials: E
authors.lastname: Bonales-Alatorre
authors.affiliation: School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas 7001, Australia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Shabala
mesh_terms: D027461:Beta vulgaris / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D001622:Betaine / Q000031:analogs & derivatives / Q000494:pharmacology; D027465:Chenopodium quinoa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D002794:Choline / Q000031:analogs & derivatives / Q000494:pharmacology*; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D054712:Salinity; D012964:Sodium / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000737:chemistry / Q000494:pharmacology; D015222:Sodium Channels / Q000378:metabolism*; D013312:Stress, Physiological; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D001622:Betaine; D012964:Sodium; D002794:Choline
keywords: Adaptation; Choline; Glycine betaine; Proline; SV channel; Salinity stress