Roles of AtTPC1, vacuolar two pore channel 1, in Arabidopsis stomatal closure.

Mohammad Mahbub Islam, Shintaro Munemasa, Mohammad Anowar Hossain, Yoshimasa Nakamura, Izumi C Mori, Yoshiyuki Murata

Graduate School of Natural Science and Technology, Okayama University, 1-1-1 Tsushima-naka, Okayama, 700-8530 Japan.

Plant & cell physiology 2010 Feb

filter terms:

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.

Citation

Mohammad Mahbub Islam, Shintaro Munemasa, Mohammad Anowar Hossain, Yoshimasa Nakamura, Izumi C Mori, Yoshiyuki Murata. Roles of AtTPC1, vacuolar two pore channel 1, in Arabidopsis stomatal closure. Plant & cell physiology. 2010 Feb;51(2):302-11