US EPA

749712 

Journal Article 

Calcium channels activated by hydrogen peroxide mediate abscisic acid signalling in guard cells 

Pei, ZM; Murata, Y; Benning, G; Thomine, S; Klüsener, B; Allen, GJ; Grill, E; Schroeder, JI 

2000 

Yes 

Nature
ISSN: 0028-0836
EISSN: 1476-4687 

406 

6797 

731-734 

English 

10963598 

10.1038/35021067 

WOS:000088767700045 

Drought is a major threat to agricultural production. Plants synthesize the hormone abscisic acid (ABA) in response to drought, triggering a signalling cascade in guard cells that results in stomatal closure, thus reducing water loss1. ABA triggers an increase in cytosolic calcium in guard cells ([Ca2+]cyt)2, 3, 4, 5, 6 that has been proposed to include Ca2+ influx across the plasma membrane3, 5, 7, 8, 9. However, direct recordings of Ca 2+ currents have been limited3 and the upstream activation mechanisms of plasma membrane Ca2+ channels remain unknown. Here we report activation of Ca2+-permeable channels in the plasma membrane of Arabidopsis guard cells by hydrogen peroxide. The H2O2-activated Ca2+ channels mediate both influx of Ca2+ in protoplasts and increases in [Ca 2+]cyt in intact guard cells. ABA induces the production of H2O2 in guard cells. If H2O2 production is blocked, ABA-induced closure of stomata is inhibited. Moreover, activation of Ca2+ channels by H2O2 and ABA- and H2O2-induced stomatal closing are disrupted in the recessive ABA-insensitive mutant gca2. These data indicate that ABA-induced H2O2 production and the H2O 2-activated Ca2+ channels are important mechanisms for ABA-induced stomatal closing.