TY  - JOUR
A1  - Huang, Shouguang
A1  - Ding, Meiqi
A1  - Roelfsema, M. Rob G.
A1  - Dreyer, Ingo
A1  - Scherzer, Sönke
A1  - Al-Rasheid, Khaled A. S
A1  - Gao, Shiqiang
A1  - Nagel, Georg
A1  - Hedrich, Rainer
A1  - Konrad, Kai R.
T1  - Optogenetic control of the guard cell membrane potential and stomatal movement by the light-gated anion channel GtACR1
JF  - Science Advances
N2  - Guard cells control the aperture of plant stomata, which are crucial for global fluxes of CO\(_2\) and water. In turn, guard cell anion channels are seen as key players for stomatal closure, but is activation of these channels sufficient to limit plant water loss? To answer this open question, we used an optogenetic approach based on the light-gated anion channelrhodopsin 1 (GtACR1). In tobacco guard cells that express GtACR1, blue- and green-light pulses elicit Cl\(^-\) and NO\(_3\)\(^-\) currents of -1 to -2 nA. The anion currents depolarize the plasma membrane by 60 to 80 mV, which causes opening of voltage-gated K+ channels and the extrusion of K+. As a result, continuous stimulation with green light leads to loss of guard cell turgor and closure of stomata at conditions that provoke stomatal opening in wild type. GtACR1 optogenetics thus provides unequivocal evidence that opening of anion channels is sufficient to close stomata.
KW  - abscisic-acid activation
KW  - Arabidopsis thaliana
KW  - H+-atpase
KW  - signal transduction
KW  - potassium channel
KW  - intact plants
KW  - K+ channels
KW  - R-type
KW  - CO2
KW  - SLAC1
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260925
VL  - 7
IS  - 28
ER  - 
TY  - JOUR
A1  - Lu, Jinping
A1  - Dreyer, Ingo
A1  - Dickinson, Miles Sasha
A1  - Panzer, Sabine
A1  - Jaślan, Dawid
A1  - Navarro-Retamal, Carlos
A1  - Geiger, Dietmar
A1  - Terpitz, Ulrich
A1  - Becker, Dirk
A1  - Stroud, Robert M.
A1  - Marten, Irene
A1  - Hedrich, Rainer
T1  - Vicia faba SV channel VfTPC1 is a hyperexcitable variant of plant vacuole two pore channels
JF  - eLife
N2  - To fire action-potential-like electrical signals, the vacuole membrane requires the two-pore channel TPC1, formerly called SV channel. The TPC1/SV channel functions as a depolarization-stimulated, non-selective cation channel that is inhibited by luminal Ca\(^{2+}\). In our search for species-dependent functional TPC1 channel variants with different luminal Ca\(^{2+}\) sensitivity, we found in total three acidic residues present in Ca\(^{2+}\) sensor sites 2 and 3 of the Ca\(^{2+}\)-sensitive AtTPC1 channel from Arabidopsis thaliana that were neutral in its Vicia faba ortholog and also in those of many other Fabaceae. When expressed in the Arabidopsis AtTPC1-loss-of-function background, wild-type VfTPC1 was hypersensitive to vacuole depolarization and only weakly sensitive to blocking luminal Ca\(^{2+}\). When AtTPC1 was mutated for these VfTPC1-homologous polymorphic residues, two neutral substitutions in Ca\(^{2+}\) sensor site 3 alone were already sufficient for the Arabidopsis At-VfTPC1 channel mutant to gain VfTPC1-like voltage and luminal Ca\(^{2+}\) sensitivity that together rendered vacuoles hyperexcitable. Thus, natural TPC1 channel variants exist in plant families which may fine-tune vacuole excitability and adapt it to environmental settings of the particular ecological niche.
KW  - A. thaliana
KW  - Brassicaceae
KW  - Fabaceae
KW  - pore
KW  - potassium channel
KW  - voltage gating
KW  - vacuolar calcium sensor
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350264
VL  - 12
ER  -