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Bulychev AA, Shapiguzov SY, Alova AV. Electrical Signals at the Plasma Membrane and Their Influence on Chlorophyll Fluorescence of Chara Chloroplasts in vivo. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1455-1466. [PMID: 38105017 DOI: 10.1134/s0006297923100048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/30/2023] [Accepted: 07/02/2023] [Indexed: 12/19/2023]
Abstract
Action potentials of plant cells are engaged in the regulation of many cell processes, including photosynthesis and cytoplasmic streaming. Excitable cells of characean algae submerged in a medium with an elevated K+ content are capable of generating hyperpolarizing electrical responses. These active responses of plasma membrane originate upon the passage of inward electric current comparable in strength to natural currents circulating in illuminated Chara internodes. So far, it remained unknown whether the hyperpolarizing electrical signals in Chara affect the photosynthetic activity. Here, we showed that the negative shift of cell membrane potential, which drives K+ influx into the cytoplasm, is accompanied by a delayed decrease in the actual yield of chlorophyll fluorescence F' and the maximal fluorescence yield Fm' under low background light (12.5 µmol m-2 s-1). The transient changes in F' and Fm' were evident only under illumination, which suggests their close relation to the photosynthetic energy conversion in chloroplasts. Passing the inward current caused an increase in pH at the cell surface (pHo), which reflected high H+/OH- conductance of the plasmalemma and indicated a decrease in cytoplasmic pH due to the H+ entry into the cell. The shifts in pHo arising in response to the first hyperpolarizing pulse disappeared upon repeated stimulation, thus indicating the long-term inactivation of plasmalemmal H+/OH- conductance. Suppression of plasmalemmal H+ fluxes did not abolish the hyperpolarizing responses and the analyzed changes in chlorophyll fluorescence. These results suggest that K+ fluxes between the extracellular medium, cytoplasm, and stroma are involved in the functional changes of chloroplasts reflected by transients of F' and Fm'.
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Affiliation(s)
| | | | - Anna V Alova
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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2
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Bulychev AA, Eremin A, von Rüling F, Alova AV. Effects of cell excitation on photosynthetic electron flow and intercellular transport in Chara. PROTOPLASMA 2023; 260:131-143. [PMID: 35482255 DOI: 10.1007/s00709-022-01747-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
Impact of membrane excitability on fluidic transport of photometabolites and their cell-to-cell passage via plasmodesmata was examined by pulse-modulated chlorophyll (Chl) microfluorometry in Chara australis internodes exposed to dim background light. The cells were subjected to a series of local light (LL) pulses with a 3-min period and a 30-s pulse width, which induced Chl fluorescence transients propagating in the direction of cytoplasmic streaming along the photostimulated and the neighboring internodes. By comparing Chl fluorescence changes induced in the LL-irradiated and the adjoining internodes, the permeability of the nodal complex for the photometabolites was assessed in the resting state and after the action potential (AP) generation. The electrically induced AP had no influence on Chl fluorescence in noncalcified cell regions but disturbed temporarily the metabolite transport along the internode and caused a disproportionally strong inhibition of intercellular metabolite transmission. In chloroplasts located close to calcified zones, Chl fluorescence increased transiently after cell excitation, which indicated the deceleration of photosynthetic electron flow on the acceptor side of photosystem I. Functional distinctions of chloroplasts located in noncalcified and calcified cell areas were also manifested in different modes of LL-induced changes of Chl fluorescence, which were accompanied by dissimilar changes in efficiency of PSII-driven electron flow. We conclude that chloroplasts located near the encrusted areas and in the incrustation-free cell regions are functionally distinct even in the absence of large-scale variations of cell surface pH. The inhibition of transnodal transport after AP generation is probably due to Ca2+-regulated changes in plasmodesmal aperture.
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Affiliation(s)
| | - Alexey Eremin
- Institute of Physics, Otto-von-Guericke University, Magdeburg, Germany
| | | | - Anna V Alova
- Faculty of Biology, Moscow State University, Moscow, Russia.
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3
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Khlopkov A, Sherstneva O, Ladeynova M, Grinberg M, Yudina L, Sukhov V, Vodeneev V. Participation of calcium ions in induction of respiratory response caused by variation potential in pea seedlings. PLANT SIGNALING & BEHAVIOR 2021; 16:1869415. [PMID: 33404323 PMCID: PMC7971294 DOI: 10.1080/15592324.2020.1869415] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 05/25/2023]
Abstract
Electrical signals in plants caused by external stimuli are capable of inducing various physiological responses. The mechanisms of transformation of a long-distance electrical signal (ES) into a functional response remain largely unexplored and require additional research. In this work, we investigated the role of calcium ions in the development of ES-induced respiratory response. Gradual heating of the leaf causes the propagation of variation potential (VP) in the pea seedling. The propagation of VP leads to a transient activation of respiration in an unaffected leaf. During the VP generation, a transient increase in the intracellular calcium concentration takes place. A calcium channel blocker inhibits the respiratory response, and a calcium ionophore induces the activation of respiration. Inhibitory analysis has showed that the VP-induced increase in respiration activity is probably associated with calcium-mediated activation of rotenone-insensitive alternative NADPH dehydrogenases in mitochondria.
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Affiliation(s)
- Andrey Khlopkov
- Department of Biophysics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Oksana Sherstneva
- Department of Biophysics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Maria Ladeynova
- Department of Biophysics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Marina Grinberg
- Department of Biophysics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Lyubov Yudina
- Department of Biophysics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Vladimir Sukhov
- Department of Biophysics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Vladimir Vodeneev
- Department of Biophysics, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
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Premkumar A, Lindberg S, Lager I, Rasmussen U, Schulz A. Arabidopsis PLDs with C2-domain function distinctively in hypoxia. PHYSIOLOGIA PLANTARUM 2019; 167:90-110. [PMID: 30417386 DOI: 10.1111/ppl.12874] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/31/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
Hypoxia (oxygen deprivation) causes metabolic disturbances at physiological, biochemical and genetic levels and results in decreased plant growth and development. Phospholipase D (PLD)-mediated signaling was reported for abiotic and biotic stress signaling events in plants. To investigate the participatory role of PLDs also in hypoxia signaling, we used wild type of Arabidopsis thaliana and 10 pld isoform mutants containing C2-domain. Hypoxia-induced changes in three major signaling players, namely, cytosolic free calcium (Ca2+ cyt ), reactive oxygen species (ROS) and phosphatidic acid (PA), were determined in mesophyll protoplasts. The Ca2+ cyt and ROS levels were monitored by fluorescence microscopy and confocal imaging, while PA levels were quantified by an enzymatic method. Our findings reveal that the elevations of cytosolic calcium and PA are reduced in all the 10 mutants dysfunctional in PLD isoforms. The hypoxia-related changes in both calcium and ROS show different kinetic patterns depending on the type of PLD studied. Pharmacological experiments confirm that both external and internal sources contribute to calcium and ROS accumulation under hypoxia. PLDα1-3, PLDβ1 and PLDγ1-3 are likely involved in calcium signaling under hypoxia as well as in PA production, while all investigated PLDs, except for PLDγ3, take part in ROS elevation.
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Affiliation(s)
- Albert Premkumar
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Sylvia Lindberg
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ida Lager
- Department of Plant Breeding, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden
| | - Ulla Rasmussen
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Alexander Schulz
- Center for Advanced Bioimaging, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Fredriksberg, Denmark
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Kaňa R, Kotabová E, Šedivá B, Kuthanová Trsková E. Photoprotective strategies in the motile cryptophyte alga Rhodomonas salina-role of non-photochemical quenching, ions, photoinhibition, and cell motility. Folia Microbiol (Praha) 2019; 64:691-703. [PMID: 31352667 DOI: 10.1007/s12223-019-00742-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 07/15/2019] [Indexed: 12/20/2022]
Abstract
We explored photoprotective strategies in a cryptophyte alga Rhodomonas salina. This cryptophytic alga represents phototrophs where chlorophyll a/c antennas in thylakoids are combined with additional light-harvesting system formed by phycobiliproteins in the chloroplast lumen. The fastest response to excessive irradiation is induction of non-photochemical quenching (NPQ). The maximal NPQ appears already after 20 s of excessive irradiation. This initial phase of NPQ is sensitive to Ca2+ channel inhibitor (diltiazem) and disappears, also, in the presence of non-actin, an ionophore for monovalent cations. The prolonged exposure to high light of R. salina cells causes photoinhibition of photosystem II (PSII) that can be further enhanced when Ca2+ fluxes are inhibited by diltiazem. The light-induced reduction in PSII photochemical activity is smaller when compared with immotile diatom Phaeodactylum tricornutum. We explain this as a result of their different photoprotective strategies. Besides the protective role of NPQ, the motile R. salina also minimizes high light exposure by increased cell velocity by almost 25% percent (25% from 82 to 104 μm/s). We suggest that motility of algal cells might have a photoprotective role at high light because algal cell rotation around longitudinal axes changes continual irradiation to periodically fluctuating light.
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Affiliation(s)
- Radek Kaňa
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic.
| | - Eva Kotabová
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic
| | - Barbora Šedivá
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic
| | - Eliška Kuthanová Trsková
- Institute of Microbiology, Centre ALGATECH, Czech Academy of Sciences, Třeboň, Czech Republic.,Student of Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
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Bulychev AA, Foissner I. Pathways for external alkalinization in intact and in microwounded Chara cells are differentially sensitive to wortmannin. PLANT SIGNALING & BEHAVIOR 2017; 12:e1362518. [PMID: 28805493 PMCID: PMC5640205 DOI: 10.1080/15592324.2017.1362518] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 07/26/2017] [Accepted: 07/27/2017] [Indexed: 05/13/2023]
Abstract
Proton flows across the plant cell membranes play a major role in electrogenesis and regulation of photosynthesis and ion balance. The profiles of external pH along the illuminated internodal cells of characean algae consist of alternating high- and low-pH zones that are spatially coordinated with the distribution of photosynthetic activity of chloroplasts underlying these zones. The results based on confocal laser scanning fluorescence microscopy, pH microsensors, and pulse-amplitude-modulated chlorophyll microfluorometry revealed that the coordination of H+ transport and photosynthesis is disrupted by the 2 different environmental cues (low light and wounding) and by a chemical, wortmannin interfering with the inositol phospholipid metabolism. On the one hand, the transition from moderate to low irradiance diminished the peaks in the profiles of photosystem II (PSII) quantum efficiency but did not remove the pH bands. On the other hand, the microwounding of the internode with a glass micropipette, impacting primarily the cell wall, resulted in a rapid local alkalinization of the external medium (by 2-2.5 pH units) near the cell surface, thus mimicking the appearance of natural pH bands. Despite their seeming similarity, the alkaline bands of intact cells were eliminated by wortmannin, whereas the wound-induced alkalinization was insensitive to this drug. Furthermore, the attenuation of natural pH bands in wortmannin-treated cells was accompanied by the enhancement in spatial heterogeneity of PSII efficiency and electron transport rates, which indicates the complexity of chloroplast-plasma membrane interactions. The results suggest that the light- and wound-induced alkaline areas on the cell surface are associated with different ion-transport systems.
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Affiliation(s)
- Alexander A. Bulychev
- Department of Biophysics, Faculty of Biology, Moscow State University, Moscow, Russia
| | - Ilse Foissner
- Department of Cell Biology and Physiology, Division of Plant Physiology, University of Salzburg, Salzburg, Austria
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Sukhov V. Electrical signals as mechanism of photosynthesis regulation in plants. PHOTOSYNTHESIS RESEARCH 2016; 130:373-387. [PMID: 27154573 DOI: 10.1007/s11120-016-0270-x] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 04/26/2016] [Indexed: 05/24/2023]
Abstract
This review summarizes current works concerning the effects of electrical signals (ESs) on photosynthesis, the mechanisms of the effects, and its physiological role in plants. Local irritations of plants induce various photosynthetic responses in intact leaves, including fast and long-term inactivation of photosynthesis, and its activation. Irritation-induced ESs, including action potential, variation potential, and system potential, probably causes the photosynthetic responses in intact leaves. Probable mechanisms of induction of fast inactivation of photosynthesis are associated with Ca2+- and (or) H+-influxes during ESs generation; long-term inactivation of photosynthesis might be caused by Ca2+- and (or) H+-influxes, production of abscisic and jasmonic acids, and inactivation of phloem H+-sucrose symporters. It is probable that subsequent development of inactivation of photosynthesis is mainly associated with decreased CO2 influx and inactivation of the photosynthetic dark reactions, which induces decreased photochemical quantum yields of photosystems I and II and increased non-photochemical quenching of photosystem II fluorescence and cyclic electron flow around photosystem I. However, other pathways of the ESs influence on the photosynthetic light reactions are also possible. One of them might be associated with ES-connected acidification of chloroplast stroma inducing ferredoxin-NADP+ reductase accumulation at the thylakoids in Tic62 and TROL complexes. Mechanisms of ES-induced activation of photosynthesis require further investigation. The probable ultimate effect of ES-induced photosynthetic responses in plant life is the increased photosynthetic machinery resistance to stressors, including high and low temperatures, and enhanced whole-plant resistance to environmental factors at least during 1 h after irritation.
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Affiliation(s)
- Vladimir Sukhov
- Department of Biophysics, N. I. Lobachevsky State University of Nizhny Novgorod, Gagarin Avenue 23, Nizhny Novgorod, Russia, 603950.
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Łabuz J, Samardakiewicz S, Hermanowicz P, Wyroba E, Pilarska M, Gabryś H. Blue light-dependent changes in loosely bound calcium in Arabidopsis mesophyll cells: an X-ray microanalysis study. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3953-64. [PMID: 26957564 PMCID: PMC4915525 DOI: 10.1093/jxb/erw089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Calcium is involved in the signal transduction pathway from phototropins, the blue light photoreceptor kinases which mediate chloroplast movements. The chloroplast accumulation response in low light is controlled by both phot1 and phot2, while only phot2 is involved in avoidance movement induced by strong light. Phototropins elevate cytosolic Ca(2+) after activation by blue light. In higher plants, both types of chloroplast responses depend on Ca(2+), and internal calcium stores seem to be crucial for these processes. Yet, the calcium signatures generated after the perception of blue light by phototropins are not well understood. To characterize the localization of calcium in Arabidopsis mesophyll cells, loosely bound (exchangeable) Ca(2+) was precipitated with potassium pyroantimonate and analyzed by transmission electron microscopy followed by energy-dispersive X-ray microanalysis. In dark-adapted wild-type Arabidopsis leaves, calcium precipitates were observed at the cell wall, where they formed spherical structures. After strong blue light irradiation, calcium at the apoplast prevailed, and bigger, multilayer precipitates were found. Spherical calcium precipitates were also detected at the tonoplast. After red light treatment as a control, the precipitates at the cell wall were smaller and less numerous. In the phot2 and phot1phot2 mutants, calcium patterns were different from those of wild-type plants. In both mutants, no elevation of calcium after blue light treatment was observed at the cell periphery (including the cell wall and a fragment of cytoplasm). This result confirms the involvement of phototropin2 in the regulation of Ca(2+) homeostasis in mesophyll cells.
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Affiliation(s)
- Justyna Łabuz
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Sławomir Samardakiewicz
- Laboratory of Electron and Confocal Microscopy, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Paweł Hermanowicz
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Elżbieta Wyroba
- Laboratory of Electron Microscopy, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Maria Pilarska
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Halina Gabryś
- Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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Hocking B, Tyerman SD, Burton RA, Gilliham M. Fruit Calcium: Transport and Physiology. FRONTIERS IN PLANT SCIENCE 2016; 7:569. [PMID: 27200042 PMCID: PMC4850500 DOI: 10.3389/fpls.2016.00569] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 04/13/2016] [Indexed: 05/18/2023]
Abstract
Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium-regulated signaling pathways that control ripening would assist in addressing calcium deficiency disorders and improving fruit pathogen resistance.
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Affiliation(s)
- Bradleigh Hocking
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
- ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Stephen D. Tyerman
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Rachel A. Burton
- ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Matthew Gilliham
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
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Bulychev AA, Komarova AV. Long-distance signal transmission and regulation of photosynthesis in characean cells. BIOCHEMISTRY (MOSCOW) 2014; 79:273-81. [DOI: 10.1134/s0006297914030134] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Abstract
"All things flow and change…even in the stillest matter there is unseen flux and movement." Attributed to Heraclitus (530-470 BC), from The Story of Philosophy by Will Durant. Heraclitus, a Greek philosopher, was thinking on a much larger scale than molecular signaling; however, his visionary comments are an important reminder for those studying signaling today. Even in unstimulated cells, signaling pathways are in constant metabolic flux and provide basal signals that travel throughout the organism. In addition, negatively charged phospholipids, such as the polyphosphorylated inositol phospholipids, provide a circuit board of on/off switches for attracting or repelling proteins that define the membranes of the cell. This template of charged phospholipids is sensitive to discrete changes and metabolic fluxes-e.g., in pH and cations-which contribute to the oscillating signals in the cell. The inherent complexities of a constantly fluctuating system make understanding how plants integrate and process signals challenging. In this review we discuss one aspect of lipid signaling: the inositol family of negatively charged phospholipids and their functions as molecular sensors and regulators of metabolic flux in plants.
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Affiliation(s)
- Wendy F Boss
- Department of Plant Biology, North Carolina State University, Raleigh, NC 27695-7649, USA.
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Krupenina NA, Bulychev AA, Schreiber U. Chlorophyll fluorescence images demonstrate variable pathways in the effects of plasma membrane excitation on electron flow in chloroplasts of Chara cells. PROTOPLASMA 2011; 248:513-522. [PMID: 20740294 DOI: 10.1007/s00709-010-0198-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 08/10/2010] [Indexed: 05/29/2023]
Abstract
Chlorophyll fluorescence Imaging and Microscopy PAM fluorometry were applied to study spatial dynamics of photosystem II quantum yield (ΔF/F'(m)) and non-photochemical quenching (NPQ) in resting and electrically stimulated Chara corallina cells in the absence and presence of the hydrophilic electron acceptor methyl viologen (MV) in the external medium. Electrical excitation of the plasma membrane temporarily enhanced the heterogeneity of photosynthetic patterns under physiological conditions (in the absence of MV), but irreversibly eliminated these patterns in the presence of MV. These findings suggest that the action potential (AP) of the excitable plant cell affects the spatial patterns of photosynthesis and chlorophyll fluorescence through different pathways operated in the absence and presence of MV. Based on the extent of NPQ as an indicator of MV-dependent electron flow, it is supposed that MV cannot permeate into the chloroplasts of photosynthetically active "acid cell regions" but gains an immediate access to the stroma of these chloroplasts after triggering of an AP. The AP-triggered MV-dependent non-photochemical quenching in the chloroplasts of acidic cell regions was routinely observed at 0.1 mM Ca(2+) in the medium but not at elevated (2 mM) external Ca(2+) concentration. The results are interpreted in terms of competition between two permeant divalent ion species, Ca(2+) and MV(2+), for their passage through the voltage-gated calcium channels of the plasma membrane. It is proposed that the herbicidal activity of MV in characean cells, here serving as model object, can be manipulated by triggering AP and varying Ca(2+) concentration in the environmental medium.
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Bulychev AA, Krupenina NA. Transient removal of alkaline zones after excitation of Chara cells is associated with inactivation of high conductance in the plasmalemma. PLANT SIGNALING & BEHAVIOR 2009; 4:727-34. [PMID: 19820298 PMCID: PMC2801383 DOI: 10.4161/psb.4.8.9306] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The action potential (AP) of excitable plant cells is a multifunctional physiological signal. Its generation in characean algae suppresses the pH banding for 15-30 min and enhances the heterogeneity of spatial distribution of photosynthetic activity. This suppression is largely due to the cessation of H(+) influx (OH(-) efflux) in the alkaline cell regions. Measurements of local pH and membrane conductance in individual space-clamped alkaline zones (small cell areas bathed in an isolated pool of external medium) showed that the AP generation is followed by the transient disappearance of alkaline zone in parallel with a large decrease in membrane conductance. These changes, specific to alkaline zones, were only observed under continuous illumination following a relaxation period of at least 15 min after previous excitation. The excitation of dark-adapted cells produced no conductance changes in the post-excitation period. The results indicate that the origin of alkaline zones in characean cells is not due to operation of electroneutral H(+)/HCO(3)(-) symport or OH(-)/HCO(3)(-) antiport. It is concluded that the membrane excitation is associated with inactivation of plasmalemma high conductance in the alkaline cell regions.
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Affiliation(s)
- Alexander A Bulychev
- Department of Biophysics, Faculty of Biology, Moscow State University, Moscow, Russia.
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14
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Abstract
In numerous plant signal transduction pathways, Ca2+ is a versatile second messenger which controls the activation of many downstream actions in response to various stimuli. There is strong evidence to indicate that information encoded within these stimulus-induced Ca2+ oscillations can provide signalling specificity. Such Ca2+ signals, or 'Ca2+ signatures', are generated in the cytosol, and in noncytosolic locations including the nucleus and chloroplast, through the coordinated action of Ca2+ influx and efflux pathways. An increased understanding of the functions and regulation of these various Ca2+ transporters has improved our appreciation of the role these transporters play in specifically shaping the Ca2+ signatures. Here we review the evidence which indicates that Ca2+ channel, Ca2+-ATPase and Ca2+ exchanger isoforms can indeed modulate specific Ca2+ signatures in response to an individual signal.
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Affiliation(s)
- Martin R McAinsh
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK;Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Jon K Pittman
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK;Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
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15
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Bulychev AA, Krupenina NA. Facilitated permeation of methyl viologen into chloroplasts in situ during electric pulse generation in excitable plant cell membranes. BIOCHEMISTRY (MOSCOW) SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2008. [DOI: 10.1134/s1990747808040132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Weinl S, Held K, Schlücking K, Steinhorst L, Kuhlgert S, Hippler M, Kudla J. A plastid protein crucial for Ca2+-regulated stomatal responses. THE NEW PHYTOLOGIST 2008; 179:675-686. [PMID: 18507772 DOI: 10.1111/j.1469-8137.2008.02492.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
* Guard cell movements are regulated by environmental cues including, for example, elevations in extracellular Ca(2+) concentration. Here, the subcellular localization and physiological function of the Ca(2+)-sensing receptor (CAS) protein was investigated. * CAS protein localization was ascertained by microscopic analyses of green fluorescent protein (GFP) fusion proteins and biochemical fractionation assays. Comparative guard cell movement investigations were performed in wild-type and cas loss-of-function mutant lines of Arabidopsis thaliana. Cytoplasmic Ca(2+) dynamics were addressed in plants expressing the yellow cameleon reporter protein YC3.6. * This study identified CAS as a chloroplast-localized protein that is crucial for proper stomatal regulation in response to elevations of external Ca(2+). CAS fulfils this role through modulation of the cytoplasmic Ca(2+) concentration. * This work reveals a novel role of the chloroplast in cellular Ca(2+) signal transduction.
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Affiliation(s)
- Stefan Weinl
- Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany
| | - Katrin Held
- Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany
| | - Kathrin Schlücking
- Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany
| | - Leonie Steinhorst
- Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany
| | - Sebastian Kuhlgert
- Institut für Biochemie und Biotechnologie der Pflanzen, Universität Münster, Hindenburgplatz 55, 48143 Münster, Germany
| | - Michael Hippler
- Institut für Biochemie und Biotechnologie der Pflanzen, Universität Münster, Hindenburgplatz 55, 48143 Münster, Germany
| | - Jörg Kudla
- Molekulare Entwicklungsbiologie der Pflanzen, Institut für Botanik und Botanischer Garten, Universität Münster, Schlossplatz 4, 48149 Münster, Germany
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Nomura H, Komori T, Kobori M, Nakahira Y, Shiina T. Evidence for chloroplast control of external Ca2+-induced cytosolic Ca2+ transients and stomatal closure. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 53:988-98. [PMID: 18088326 DOI: 10.1111/j.1365-313x.2007.03390.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The role of guard cell chloroplasts in stomatal function is controversial. It is usually assumed that stomatal closure is preceded by a transient increase in cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)) in the guard cells. Here, we provide the evidence that chloroplasts play a critical role in the generation of extracellular Ca(2+) ([Ca(2+)](ext))-induced [Ca(2+)](cyt) transients and stomatal closure in Arabidopsis. CAS (Ca(2+) sensing receptor) is a plant-specific putative Ca(2+)-binding protein that was originally proposed to be a plasma membrane-localized external Ca(2+) sensor. In the present study, we characterized the intracellular localization of CAS in Arabidopsis with a combination of techniques, including (i) in vivo localization of green fluorescent protein (GFP) fused gene expression, (ii) subcellular fractionation and fractional analysis of CAS with Western blots, and (iii) database analysis of thylakoid membrane proteomes. Each technique produced consistent results. CAS was localized mainly to chloroplasts. It is an integral thylakoid membrane protein, and the N-terminus acidic Ca(2+)-binding region is likely exposed to the stromal side of the membrane. The phenotype of T-DNA insertion CAS knockout mutants and cDNA mutant-complemented plants revealed that CAS is essential for stomatal closure induced by external Ca(2+). In contrast, overexpression of CAS promoted stomatal closure in the absence of externally applied Ca(2+). Furthermore, using the transgenic aequorin system, we showed that [Ca(2+)](ext)-induced [Ca(2+)](cyt) transients were significantly reduced in CAS knockout mutants. Our results suggest that thylakoid membrane-localized CAS is essential for [Ca(2+)](ext)-induced [Ca(2+)](cyt) transients and stomatal closure.
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Affiliation(s)
- Hironari Nomura
- Graduate School of Human and Environmental Sciences, Kyoto Prefectural University, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
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Affiliation(s)
- Alex A R Webb
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
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