Ingo Dreyer

Universidad de Talca · Center for Bioinformatics Simulations and Modelling (CBSM)

Plants depend on transport processes for correct allocation of specialized metabolites. This is important for optimal defense, avoidance of autotoxicity, connecting compartmented biosynthetic modules and more. Transport of a wide variety of specialized metabolites is mediated by transporters from the Nitrate and Peptide transporter Family (NPF), wh...

Transport processes across membranes play central roles in any biological system. They are essential for homeostasis, cell nutrition, and signaling. Fluxes across membranes are governed by fundamental thermodynamic rules and are influenced by electrical potentials and concentration gradients. Transmembrane transport processes have been largely stud...

Two-pore channels (TPCs) are members of the superfamily of ligand-gated and voltage-sensitive ion channels in the membranes of intracellular organelles of eukaryotic cells. The evolution of ordinary plant TPC1 essentially followed a very conservative pattern, with no changes in the characteristic structural footprints of these channels, such as the...

Since the 19th century, it has been known that the carnivorous Venus flytrap is electrically excitable. Nevertheless, the mechanism and the molecular entities of the flytrap action potential (AP) remain unknown. When entering the electrically excitable stage, the trap expressed a characteristic inventory of ion transporters, among which the increas...

Sensing of external mineral nutrient concentrations is essential for plants to colonize environments with a large spectrum of nutrient availability. Here we analyzed transporter networks in computational cell biology simulations to understand better the initial steps of this sensing process. The networks analyzed were capable of translating the inf...

Glucosinolate transporters (GTRs) are part of the nitrate/peptide transporter (NPF) family, members of which also transport specialized secondary metabolites as substrates. Glucosinolates are defense compounds derived from amino acids. We selected 4-methylthiobutyl (4MTB) and indol-3-ylmethyl (I3M) glucosinolates to study how GTR1 from Arabidopsis...

To fire action-potential-like electrical signals, the vacuole membrane requires the depolarization-activated two-pore channel TPC1, also called S lowly activating V acuolar SV channel. The TPC1/SV channel, encoded by the TPC1 gene, functions as a voltage-dependent and Ca ²⁺ -regulated potassium channel. TPC1 currents are activated by a rise in cyto...

Two Pore Channels (TPCs) are cation-selective voltage- and ligand-gated ion channels in membranes of intracellular organelles of eukaryotic cells. In plants, the TPC1 subtype forms the slowly activating vacuolar (SV) channel, the most dominant ion channel in the vacuolar membrane. Controversial reports about the permeability properties of plant SV...

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 an...

Plants, as sessile organisms, gained the ability to sense and respond to biotic and abiotic stressors to survive severe changes in their environments. The change in our climate comes with extreme dry periods but also episodes of flooding. The latter stress condition causes anaerobiosis-triggered cytosolic acidosis and impairs plant function. The mo...

Homeostasis in living cells refers to the steady state of internal, physical, and chemical conditions. It is sustained by self-regulation of the dynamic cellular system. To gain insight into the homeostatic mechanisms that maintain cytosolic nutrient concentrations in plant cells within a homeostatic range, we performed computational cell biology e...

Plants synthesize a large number of natural products, many of which are bioactive and have practical values as well as commercial potential. To explore this vast structural diversity, we present PSC-db, a unique plant metabolite database aimed to categorize the diverse phytochemical space by providing 3D-structural information along with physicoche...

HKT channels are a plant protein family involved in sodium (Na+) and potassium (K+) uptake and Na+-K+ homeostasis. Some HKTs underlie salt tolerance responses in plants, while others provide a mechanism to cope with short-term K+ shortage by allowing increased Na+ uptake under K+ starvation conditions. HKT channels present a functionally versatile...

Cytosolic calcium signals are evoked by a large variety of biotic and abiotic stimuli and play an important role in cellular and long distance signalling in plants. While the function of the plasma membrane in cytosolic Ca ²⁺ signalling has been intensively studied, the role of the vacuolar membrane remains elusive. A newly developed vacuolar volta...

The carnivorous plant Dionaea muscipula harbors multicellular trigger hairs designed to sense mechanical stimuli upon contact with animal prey. At the base of the trigger hair, mechanosensation is transduced into an all-or-nothing action potential (AP) that spreads all over the trap, ultimately leading to trap closure and prey capture. To reveal th...

Significance People for centuries are puzzled how living creatures like plants sense their environment. Plants employ electrical signals to communicate a cue-dependent local status between plants cells and organs. As a first response to biotic and abiotic stresses, the membrane potential of plant cells depolarizes. Recovery from the depolarized sta...

Phylogenetic analysis can be a powerful tool for generating hypotheses regarding the evolution of physiological processes. Here, we provide an updated view of the evolution of the main cation channels in plant electrical signalling: the Shaker family of voltage-gated potassium channels and the two-pore cation (K⁺) channel (TPC1) family. Strikingly,...

Climatic change is pointed as one of the major challenges for global food security. Based on current models of climate change, reduction in precipitations and in turn, increase in the soil salinity will be a sharp constraint for crops productivity worldwide. In this context, root fungi appear as a new strategy to improve plant ecophysiological perf...

Plants have to absorb essential nutrients from the soil and do this via specialized membrane proteins. Groundbreaking studies about half a century ago led to the identification of different nutrient uptake systems in plant roots. Historically, they have been characterized as “high-affinity” uptake systems acting at low nutrient concentrations or as...

This article comments on: Villette J, Cuéllar T, Zimmermann SD, Verdeil JL, Gaillard I. 2019. Unique features of the grapevine VvK5.1 channel support novel functions for outward K+ channels in plants. Journal of Experimental Botany 70, 6181–6193.

Background HKT channels mediate sodium uniport or sodium and potassium symport in plants. Monocotyledons express a higher number of HKT proteins than dicotyledons, and it is only within this clade of HKT channels that cation symport mechanisms are found. The prevailing ion composition in the extracellular medium affects the transport abilities of v...

In contrast to the plasma membrane, the vacuole membrane has not yet been associated with electrical excitation of plants. Here, we show that mesophyll vacuoles from Arabidopsis sense and control the membrane potential essentially via the K +-permeable TPC1 and TPK channels. Electrical stimuli elicit transient depolarization of the vacuole membrane...

Extracellular adenosine 5′‐triphosphate (eATP) is an essential signaling molecule that mediates different cellular processes through its interaction with membrane‐associated receptor proteins in animals and plants. eATP regulates plant growth, development, and responses to biotic and abiotic stresses. Its accumulation in the apoplast induces ROS pr...

• To get insights into the dynamics of nutrient exchange in arbuscular mycorrhizal (AM) symbiosis, we modelled mathematically the two-membrane system at the plant-fungus interface and simulated its dynamics. • In computational cell biology experiments, the full range of nutrient transport pathways was tested for their ability to exchange P/C/N-sour...

HKT channels mediate sodium uniport or sodium and potassium symport in plants. Monocotyledons express a higher number of HKT proteins than dicotyledons, and it is only within this clade of HKT channels that cation symport mechanisms are found. The prevailing ion composition in the extracellular medium affects the transport abilities of various HKT...

One sentence abstract Immune modulation by metabolites in plant fungus interaction Abstract Extracellular adenosine 5′-triphosphate (eATP) is an essential signaling molecule that mediates different cellular processes through its interaction with membrane-associated receptor proteins in animals and plants. eATP regulates plant growth, development a...

The seed is the most important plant reproductive unit responsible for the evolutionary success of flowering plants. Aside from its essential function in the sexual reproduction of plants, the seed also represents the most economically important agricultural product worldwide, providing energy, nutrients, and raw materials for human nutrition, live...

The sections in this article are Introduction Voltage Gating from a Mechanistic Point of View Voltage‐Gated Ion Channels Uncovered in Plants and Their Involvements in Physiological Processes Gating Modifiers Outlook – Voltage‐Gated Ion Channels in ‘Systems Biology’

Fast responses to an external threat depend on the rapid transmission of signals through a plant. Action potentials (APs) are proposed as such signals. Plant APs share similarities with their animal counterparts; they are proposed to depend on the activity of voltage-gated ion channels. Nonetheless, despite their demonstrated role in (a)biotic stre...

The Arabidopsis K⁺ channel KAT1 complements in K⁺-limited medium the growth of the K⁺ uptake defective Saccharomyces cerevisiae mutant strain CY162, while another K⁺ channel, AKT2, does not. To gain insight into the structural basis for this difference, we constructed 12 recombinant chimeric channels from these two genes. When expressed in CY162, o...

Engineering artificial networks from modular components is a major challenge in synthetic biology. In the past years, single units, such as switches and oscillators, were successfully constructed and implemented. The effective integration of these parts into functional artificial self-regulated networks is currently on the verge of breakthrough. He...

Supporting information file containing a description of our deterministic mathematical model (Text and Equations in S1 file) and six supporting figures. Figure A: Network of coupled repressilators without lactonase; Figure B: The plasmids pCCB1 and pCCB2 were designed with restriction sites flanking the genes of interest; Figure C: Acyl-HSL synthas...

The functionality of the assembled communication circuit was tested in the presence of IPTG. Data shows that the expression of gfp was initiated by an analogue of lactose (IPTG) that eliminates suppression of the PLlac01 promoters. Images at 30x magnification were acquired during 1080 min. At least three biological replicates of each experiment wer...

Synchronization of repressilators in clusters of various sizes in a population of E. coli. The number of cells within clusters varies over time, because cells change the phase of oscillations in the initial, clustering stage. Images at 30x magnification were acquired during 1080 min. At least three biological replicates of each experiment were perf...

The functionality of the assembled communication circuit was tested by following the GFP expression over time in cells transformed with the communication circuit alone. Data shows that cells are unable to express gfp over the curse of the experiment due to the LacI repression. Images at 30x magnification were acquired during 1080 min. At least thre...

Contents I. II. III. IV. V. VI. VII. VIII. References SUMMARY: Plant roots absorb potassium ions from the soil and transport them in the xylem via the transpiration stream to the shoots. There, in source tissues where sufficient chemical energy (ATP) is available, K(+) is loaded into the phloem and then transported with the phloem stream to other p...

The potassium channel AKT2 plays important roles in phloem loading and unloading. It can operate as inward-rectifying channel that allows H+-ATPase-energized K+ uptake. Moreover, through reversible post-translational modifications it can also function as an open, K+-selective channel, which taps a ‘potassium battery’, providing additional energy fo...

Commercial strawberry, Fragaria x ananassa Duch., is a species sensitive to salinity. Under saline conditions, Na(+) uptake by the plant is increased, while K(+) uptake is significantly reduced. Maintaining an adequate K(+)/Na(+) cytosolic ratio determines the ability of the plant to survive in saline environments. The goal of the present work was...

In plant science, we are currently at the dawn of an era, in which mathematical modeling and computational simulations will influence and boost tremendously the gain of new knowledge. However, for many plant scientists mathematical modeling is still rather dubious and is often negligently considered as an oversimplification of the real situation. T...

About a decade ago, members of a new protein family of anion channels were discovered on the basis of their ability to confer on plants the tolerance toward toxic aluminum ions in the soil. The efflux of Al3+-chelating malate anions through these channels is stimulated by external Al3+ ions. This feature of a few proteins determined the name of the...

In arbuscular mycorrhizal (AM) symbiosis, fungi and plants exchange nutrients (sugars and phosphate, for instance) for reciprocal benefit. Until now it is not clear how this nutrient exchange system works. Here, we used computational cell biology to simulate the dynamics of a network of proton pumps and proton-coupled transporters that are upregula...

The two‐pore cation channel TPC1 operates as a dimeric channel in animal and plant endomembranes. Each subunit consists of two homologous Shaker‐like halves, with 12 transmembrane domains in total (S1‐S6, S7‐S12). In plants, TPC1 channels reside in the vacuolar membrane, and upon voltage stimulation, give rise to the well‐known slow‐activating SV c...

Electrical signalling over long distances is an efficient way of achieving cell-to-cell communication in living organisms. In plants, the phloem can be considered as a 'green cable' that allows the transmission of action potentials (APs) induced by stimuli such as wounding and cold. Measuring phloem potential changes and separating them from second...

Voltage-gated potassium (K +) channels are present in all living systems. Despite high structural similarities in the transmembrane domains (TMD), this K + channel type segregates into at least two main functional categories—hyperpolarization-activated, inward-rectifying (K in) and depolarization-activated, outward-rectifying (K out) channels. Volt...

During the transition from water to land, plants had to cope with the loss of water through transpiration, the inevitable result of photosynthetic CO2 fixation on land [1, 2]. Control of transpiration became possible through the development of a new cell type: guard cells, which form stomata. In vascular plants, stomatal regulation is mediated by t...

Two-pore domain potassium (K2P) channels are membrane proteins widely identified in mammals, plants, and other organisms. A functional channel is a dimer with each subunit comprising two pore-forming loops and four transmembrane domains. The genome of the model plant Arabidopsis thaliana harbors five genes coding for K2P channels. Homologs of Arabi...

The Kv-like K+ channels at the plasma membrane, including the inward-rectifying KAT1 K+ channel of Arabidopsis, are important targets for manipulating K+ homeostasis in plants. Gating modification, especially, has been identified as a promising means by which to engineer plants with improved characteristics in mineral and water use. Understanding p...

Many plants species deal with aluminum (Al) toxicity that limits crop production on acid soils by releasing organic acid anions from the root, thereby immobilizing Al3+ in the rhizosphere and preventing it from entering the root. Members of the ALMT (Al-activated malate transporter) and MATE (multidrug and toxic compound efflux) transporter familie...

Triticum aestivum aluminum-activated malate transporter (TaALMT1) is the founding member of a unique gene family of anion transporters (ALMTs) that mediate the efflux of organic acids. A small sub-group of root-localized ALMTs, including TaALMT1, is physiologically associated with in planta aluminum (Al) resistance. TaALMT1 exhibits significant enh...

Proton-driven Suc transporters allow phloem cells of higher plants to accumulate Suc to more than 1 M, which is up to ∼1000-fold higher than in the surrounding extracellular space. The carrier protein can accomplish this task only because proton and Suc transport are tightly coupled. This study provides insights into this coupling by resolving the...