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The desert plant Phoenix dactylifera closes stomata via nitrate‐regulated SLAC 1 anion channel
Author(s) -
Müller Heike M.,
Schäfer Nadine,
Bauer Hubert,
Geiger Dietmar,
Lautner Silke,
Fromm Jörg,
Riederer Markus,
Bueno Amauri,
Nussbaumer Thomas,
Mayer Klaus,
Alquraishi Saleh A.,
Alfarhan Ahmed H.,
Neher Erwin,
AlRasheid Khaled A. S.,
Ache Peter,
Hedrich Rainer
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14672
Subject(s) - guard cell , phoenix dactylifera , abscisic acid , transpiration , botany , chemistry , biophysics , nitrate reductase , horticulture , biology , nitrate , palm , biochemistry , photosynthesis , physics , quantum mechanics , gene , organic chemistry
Summary Date palm Phoenix dactylifera is a desert crop well adapted to survive and produce fruits under extreme drought and heat. How are palms under such harsh environmental conditions able to limit transpirational water loss? Here, we analysed the cuticular waxes, stomata structure and function, and molecular biology of guard cells from P. dactylifera . To understand the stomatal response to the water stress phytohormone of the desert plant, we cloned the major elements necessary for guard cell fast abscisic acid ( ABA ) signalling and reconstituted this ABA signalosome in Xenopus oocytes. The Phoenix SLAC 1‐type anion channel is regulated by ABA kinase Pd OST 1. Energy‐dispersive X‐ray analysis ( EDXA ) demonstrated that date palm guard cells release chloride during stomatal closure. However, in Cl − medium, Pd OST 1 did not activate the desert plant anion channel Pd SLAC 1 per se . Only when nitrate was present at the extracellular face of the anion channel did the OST 1‐gated Pd SLAC 1 open, thus enabling chloride release. In the presence of nitrate, ABA enhanced and accelerated stomatal closure. Our findings indicate that, in date palm, the guard cell osmotic motor driving stomatal closure uses nitrate as the signal to open the major anion channel SLAC 1. This initiates guard cell depolarization and the release of anions together with potassium.