TY  - JOUR
A1  - Huang, Shouguang
A1  - Waadt, Rainer
A1  - Nuhkat, Maris
A1  - Kollist, Hannes
A1  - Hedrich, Rainer
A1  - Roelfsema, M. Rob G.
T1  - Calcium signals in guard cells enhance the efficiency by which abscisic acid triggers stomatal closure
T2  - New Phytologist
N2  - During drought, abscisic acid (ABA) induces closure of stomata via a signaling pathway that involves the calcium (Ca2+)-independent protein kinase OST1, as well as Ca2+-dependent protein kinases. However, the interconnection between OST1 and Ca2+ signaling in ABA-induced stomatal closure has not been fully resolved.

ABA-induced Ca2+ signals were monitored in intact Arabidopsis leaves, which express the ratiometric Ca2+ reporter R-GECO1-mTurquoise and the Ca2+-dependent activation of S-type anion channels was recorded with intracellular double-barreled microelectrodes.

ABA triggered Ca2+ signals that occurred during the initiation period, as well as in the acceleration phase of stomatal closure. However, a subset of stomata closed in the absence of Ca2+ signals. On average, stomata closed faster if Ca2+ signals were elicited during the ABA response. Loss of OST1 prevented ABA-induced stomatal closure and repressed Ca2+ signals, whereas elevation of the cytosolic Ca2+ concentration caused a rapid activation of SLAC1 and SLAH3 anion channels.

Our data show that the majority of Ca2+ signals are evoked during the acceleration phase of stomatal closure, which is initiated by OST1. These Ca2+ signals are likely to activate Ca2+-dependent protein kinases, which enhance the activity of S-type anion channels and boost stomatal closure.
KW  - abscisic acid (ABA)
KW  - Ca2+- indicator
KW  - cytosolic Ca2+ signals
KW  - OST1 protein kinase
KW  - R-GECO1-mTurquoise
KW  - SLAC1 and SLAH3 anion channels
KW  - stomata
Y1  - 2019
UR  - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/32271
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-322716
VL  - 224
ER  -