title: Roles of AtTPC1, vacuolar two pore channel 1, in Arabidopsis stomatal closure.
abstract: Abscisic acid (ABA) induces production of reactive oxygen species (ROS) and nitric oxide (NO), elevation of the cytosolic free calcium ion concentration ([Ca(2+)](cyt)) and cytosolic pH (pH(cyt)), and activation of S-type anion channels in guard cells, causing stomatal closure. To investigate whether Arabidopsis Two pore channel 1 (AtTPC1) that encodes the slow vacuolar (SV) channel is involved in stomatal closure, we examined stomatal movements and mobilization of second messengers in the attpc1-2 loss-of-function mutant in response to ABA, methyl jasmonate (MeJA) and Ca(2+). Both ABA and MeJA elicited production of ROS and NO, [Ca(2+)](cyt) oscillations, cytosolic alkalization and activation of S-type anion channel currents to lead to stomatal closure in the attpc1-2 mutant as well as the wild type. Unlike the wild type, in the attpc1-2 mutant exogenous Ca(2+) neither induced stomatal closure nor activated plasma membrane S-type anion channel currents despite [Ca(2+)](cyt) elevation. These results indicate that AtTPC1 functions in response to external Ca(2+) but not to ABA and MeJA in Arabidopsis guard cells and suggest that AtTPC1 could be involved in priming of plasma membrane S-type anion channels by external Ca(2+) in Arabidopsis guard cells.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, 1-1-1 Tsushima-naka, Okayama, 700-8530 Japan.
authors.forename: Mohammad Mahbub
authors.initials: MM
authors.lastname: Islam
authors.forename: Shintaro
authors.initials: S
authors.lastname: Munemasa
authors.forename: Mohammad Anowar
authors.initials: MA
authors.lastname: Hossain
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Izumi C
authors.initials: IC
authors.lastname: Mori
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Murata
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000085:Acetates / Q000494:pharmacology; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D009569:Nitric Oxide / Q000096:biosynthesis; D054883:Oxylipins / Q000494:pharmacology; D054046:Plant Stomata / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D000097903:Two-Pore Channels
chemical_list: D000040:Abscisic Acid; D000085:Acetates; D029681:Arabidopsis Proteins; D002118:Calcium; D015220:Calcium Channels; D003517:Cyclopentanes; D009569:Nitric Oxide; D054883:Oxylipins; D017382:Reactive Oxygen Species; C498240:TPC1 protein, Arabidopsis; D000097903:Two-Pore Channels; C072239:methyl jasmonate