TY  - JOUR
A1  - Dreyer, Ingo
A1  - Gomez-Porras, Judith Lucia
A1  - Riaño-Pachón, Diego Mauricio
A1  - Hedrich, Rainer
A1  - Geiger, Dietmar
T1  - Molecular Evolution of Slow and Quick Anion Channels (SLACs and QUACs/ALMTs)
JF  - Frontiers in Plant Science
N2  - Electrophysiological analyses conducted about 25 years ago detected two types of anion channels in the plasma membrane of guard cells. One type of channel responds slowly to changes in membrane voltage while the other responds quickly. Consequently, they were named SLAC, for SLow Anion Channel, and QUAC, for QUick Anion Channel. Recently, genes SLAC1 and QUAC1/ALMT12, underlying the two different anion current components, could be identified in the model plant Arabidopsis thaliana. Expression of the gene products in Xenopus oocytes confirmed the quick and slow current kinetics. In this study we provide an overview on our current knowledge on slow and quick anion channels in plants and analyze the molecular evolution of ALMT/QUAC-like and SLAC-like channels. We discovered fingerprints that allow screening databases for these channel types and were able to identify 192 (177 non-redundant) SLAC-like and 422 (402 non-redundant) ALMT/QUAC-like proteins in the fully sequenced genomes of 32 plant species. Phylogenetic analyses provided new insights into the molecular evolution of these channel types. We also combined sequence alignment and clustering with predictions of protein features, leading to the identification of known conserved phosphorylation sites in SLAC1-like channels along with potential sites that have not been yet experimentally confirmed. Using a similar strategy to analyze the hydropathicity of ALMT/QUAC-like channels, we propose a modified topology with additional transmembrane regions that integrates structure and function of these membrane proteins. Our results suggest that cross-referencing phylogenetic analyses with position-specific protein properties and functional data could be a very powerful tool for genome research approaches in general.
KW  - anion channel
KW  - evolution
KW  - SLAC/SLAH
KW  - ALMT
KW  - QUAC
KW  - voltage dependent
KW  - topology
KW  - phosphorylation
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189345
SN  - 1664-462X
VL  - 3
ER  - 
TY  - JOUR
A1  - Jones, Jeffrey J.
A1  - Huang, Shouguang
A1  - Hedrich, Rainer
A1  - Geilfus, Christoph‐Martin
A1  - Roelfsema, M. Rob G.
T1  - The green light gap: a window of opportunity for optogenetic control of stomatal movement
JF  - New Phytologist
N2  - Green plants are equipped with photoreceptors that are capable of sensing radiation in the ultraviolet‐to‐blue and the red‐to‐far‐red parts of the light spectrum. However, plant cells are not particularly sensitive to green light (GL), and light which lies within this part of the spectrum does not efficiently trigger the opening of stomatal pores. Here, we discuss the current knowledge of stomatal responses to light, which are either provoked via photosynthetically active radiation or by specific blue light (BL) signaling pathways. The limited impact of GL on stomatal movements provides a unique option to use this light quality to control optogenetic tools. Recently, several of these tools have been optimized for use in plant biological research, either to control gene expression, or to provoke ion fluxes. Initial studies with the BL‐activated potassium channel BLINK1 showed that this tool can speed up stomatal movements. Moreover, the GL‐sensitive anion channel GtACR1 can induce stomatal closure, even at conditions that provoke stomatal opening in wild‐type plants. Given that crop plants in controlled‐environment agriculture and horticulture are often cultivated with artificial light sources (i.e. a combination of blue and red light from light‐emitting diodes), GL signals can be used as a remote‐control signal that controls stomatal transpiration and water consumption.
KW  - anion channel
KW  - channelrhodopsin
KW  - Chl
KW  - guard cell
KW  - ion channel
KW  - light‐gated
KW  - membrane potential
KW  - phototropin
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293724
VL  - 236
IS  - 4
SP  - 1237
EP  - 1244
ER  -