Using Plant Cells of Nitellopsis obtusa for Biophysical Education

Background In this review, we summarize data concerning action potentials (APs) – long-distance electrical signals in Characean algae and liverworts. These lineages are key in understanding the mechanisms of plant terrestrialization. Liverworts are postulated to be pioneer land plants, whereas aquatic Charophytes are considered the closest relatives to land plants. The drastic change of the habitat was coupled with the adaptation of signalling systems to the new environment. Scope APs fulfil the “all-or-nothing” law, exhibit refractory periods, and propagate with a uniform velocity. Their ion mechanism in the algae and liverworts consists of a Ca 2+ influx (from external and internal stores) followed by/coincident with a Cl - efflux, which both evoke the membrane potential depolarization, and a K + efflux leading to the repolarization. The molecular identity of ion channels responsible for these fluxes remains unknown. Publication of the Chara braunii and Marchantia polymorpha genomes opened new possibilities for studying the molecular basis of APs. Here we present the list of genes which can participate in AP electrogenesis. We also point out the differences between these plant species, e.g. the absence of Ca 2+-permeable glutamate receptors (GLRs) and Cl --permeable SLAC1 channel homologues in the Chara genome. Both these channels play a vital role in long-distance signalling in liverworts and vascular plants. Among the common properties of APs in liverworts and higher plants is the duration of APs (dozens of seconds) and the speed of propagation (mm s -1), which are much slower than in the algae (seconds, and dozens of mm s -1, respectively). Conclusions Future studies with combined application of electrophysiological and molecular techniques should unravel ion channel proteins responsible for AP generation, their regulation, and transduction of those signals to physiological responses. This should also help to understand the adaptation of the signalling systems to the land environment and further evolution of APs in vascular plants.

show abstract

Impact of Mammalian Two-Pore Channel Inhibitors on Long-Distance Electrical Signals in the Characean Macroalga Nitellopsis obtusa and the Early Terrestrial Liverwort Marchantia polymorpha

Koselski

Pupkis

Hashimoto

et al. 2021

Plants

Self Cite

View full text Add to dashboard Cite

Inhibitors of human two-pore channels (TPC1 and TPC2), i.e., verapamil, tetrandrine, and NED-19, are promising medicines used in treatment of serious diseases. In the present study, the impact of these substances on action potentials (APs) and vacuolar channel activity was examined in the aquatic characean algae Nitellopsis obtusa and in the terrestrial liverwort Marchantia polymorpha. In both plant species, verapamil (20–300 µM) caused reduction of AP amplitudes, indicating impaired Ca2+ transport. In N. obtusa, it depolarized the AP excitation threshold and resting potential and prolonged AP duration. In isolated vacuoles of M. polymorpha, verapamil caused a reduction of the open probability of slow vacuolar SV/TPC channels but had almost no effect on K+ channels in the tonoplast of N. obtusa. In both species, tetrandrine (20–100 µM) evoked a pleiotropic effect: reduction of resting potential and AP amplitudes and prolongation of AP repolarization phases, especially in M. polymorpha, but it did not alter vacuolar SV/TPC activity. NED-19 (75 µM) caused both specific and unspecific effects on N. obtusa APs. In M. polymorpha, NED-19 increased the duration of repolarization. However, no inhibition of SV/TPC channels was observed in Marchantia vacuoles, but an increase in open probability and channel flickering. The results indicate an effect on Ca2+ -permeable channels governing plant excitation.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

hi@scite.ai

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Using Plant Cells of Nitellopsis obtusa for Biophysical Education

Cited by 3 publications

References 42 publications

Inositol hexakisphosphate (IP6) enhances the electrical excitability of Characean Nitellopsis obtusa

Inositol hexakisphosphate (IP6) enhances the electrical excitability of Characean Nitellopsis obtusa

Evolution of long-distance signalling upon plant terrestrialization: comparison of action potentials in Characean algae and liverworts

Impact of Mammalian Two-Pore Channel Inhibitors on Long-Distance Electrical Signals in the Characean Macroalga Nitellopsis obtusa and the Early Terrestrial Liverwort Marchantia polymorpha

Contact Info

Product

Resources

About