Phospholipase C is required for the control of stomatal aperture by ABA.
The calcium-releasing second messenger inositol 1,4,5-trisphosphate is involved in the regulation of stomatal aperture by ABA. In other signalling pathways, inositol 1,4,5-trisphosphate is generated by the action of phospholipase C. We have studied the importance of phospholipase C in guard cell ABA-signalling pathways. Immunolocalisation of a calcium-activated phospholipase C confirmed the presence of phospholipase C in tobacco guard cells. Transgenic tobacco plants with considerably reduced levels of phospholipase C in their guard cells were only partially able to regulate their stomatal apertures in response to ABA. These results suggest that phospholipase C is involved in the amplification of the calcium signal responsible for reductions in stomatal aperture in response to ABA. As full ABA-induced inhibition of stomatal opening was not observed, our results support a role for the action of other calcium-releasing second messengers in the guard cell ABA-signalling pathway. It is not known whether these different calcium-releasing second messengers act in the same or parallel ABA-signalling pathways.
Hunt
Lee
L
Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
Mills
Lewis N
LN
Pical
Christophe
C
Leckie
Calum P
CP
Aitken
Fiona L
FL
Kopka
Joachim
J
Mueller-Roeber
Bernd
B
McAinsh
Martin R
MR
Hetherington
Alistair M
AM
Gray
Julie E
JE
D000040:Abscisic Acid / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D004190:Disasters; D015870:Gene Expression; D018515:Plant Leaves / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics; D030821:Plants, Genetically Modified; D015398:Signal Transduction / Q000187:drug effects*; D014026:Nicotiana / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism*
D000040:Abscisic Acid; D010738:Type C Phospholipases; D002118:Calcium