Free Ca2+ and cytoplasmic streaming in the alga Chara

Williamson, R. E.; Ashley, C. C.

doi:10.1038/296647a0

Cited by 424 publications

(190 citation statements)

References 37 publications

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“…Generally, plant maintains a low level of Ca 2+ in cytoplasm by regulating membrane Ca 2+ transport and the intracellular Ca 2+ pools (Song and Fu, 1997). Under abiotic stresses, Ca 2+ was released into cytoplasm from cell walls and vacuoles through Ca 2+ channel, the activation of Ca 2+ pools, the reduction of Ca 2+ pump functions and the Na + -Ca 2+ exchange system (Liu et al, 2010;Saunders and Hepler, 1981;Williamson and Ashley, 1982). Our observation also indicated that Ca 2+ level rose accordingly with increasing exposure time to the cold stress, resulting in the accumulation of Ca 2+ in cytoplasm.…”

Section: Discussionsupporting

confidence: 57%

Changes in Cell Ca2+ Distribution in Loquat Leaves and Its Effects on Cold Tolerance

Zheng¹,

Dong-ming²,

Niu³

et al. 2014

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Calcium has been associated with improved cold tolerance in many crops. The aim of this study was to investigate the changes in leaf cell Ca 2+ distribution and cell organelle ultrastructure of loquat (Eriobotrya japonica Lindl.) plants in response to cold stress at -3°C, using transmission electron microscopy (TEM). Two loquat accessions, Zaozhong 6 (a commercial cultivar) and oakleaf loquat (a wild relative) were used. Cold tolerance, as measured by leaf browning rate, was higher in oakleaf plants, and calcium treatment improved cold tolerance in both species. Cold stress first induced inward transport of Ca 2+ from the intracellular space. Then, the imported Ca 2+ was aggregated around the chloroplast membrane, finally entering the chloroplast. This pattern of Ca 2+ distribution in leaf cells occurred earlier in Zaozhong 6 than in the wild loquat. With increasing time of cold exposure, the chloroplast membranes of Zaozhong 6 leaves were damaged, blurred and even disappeared, while those of wild oakleaf loquat leaves maintained their structure longer. In Zaozhong 6, cold stress induced a clear cavity between poorly structured granal thylakoids and vesicles appearing inside the chloroplast, while in oakleaf leaves cold stress had little effect on the ultrastructure of chloroplasts (although chloroplast membranes looked blurred). Loquat leaves accumulated free calcium ions around chloroplasts in response to cold stress, with earlier calcium accumulation occurring in the cold-sensitive cultivar Zaozhong 6 than in wild oakleaf loquat. These results demonstrate that these two loquat species have differences in both cold tolerance and calcium accumulation dynamics.

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Section: Discussionsupporting

confidence: 57%

Changes in Cell Ca2+ Distribution in Loquat Leaves and Its Effects on Cold Tolerance

Zheng¹,

Dong-ming²,

Niu³

et al. 2014

HST

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“…The Ca 2ϩ activities were selected to embrace the range of [Ca 2ϩ ] c that occurs physiologically, i.e. 0.2 m in resting cells to 6 m during the action potential (Williamson and Ashley, 1982). Figure 2A shows that at the resting pH of 7.8, Cl Ϫ efflux increased as a function of [Ca 2ϩ ] c , as shown previously by Shiina and Tazawa (1988).…”

Section: Direct Effect Of Ph Cmentioning

confidence: 51%

Control of Cl− Efflux in Chara corallina by Cytosolic pH, Free Ca2+, and Phosphorylation Indicates a Role of Plasma Membrane Anion Channels in Cytosolic pH Regulation1

1998

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Enhanced Cl ؊ efflux during acidosis in plants is thought to play a role in cytosolic pH (pH c ) homeostasis by short-circuiting the current produced by the electrogenic H ؉ pump, thereby facilitating enhanced H ؉ efflux from the cytosol. Using an intracellular perfusion technique, which enables experimental control of medium composition at the cytosolic surface of the plasma membrane of charophyte algae (Chara corallina), we show that lowered pH c activates Cl ؊ efflux via two mechanisms. The first is a direct effect of pH c on Cl ؊ efflux; the second mechanism comprises a pH cinduced increase in affinity for cytosolic free Ca 2؉ ([Ca 2؉ ] c ), which also activates Cl ؊ efflux. Cl Plasma membrane anion channels play fundamental roles in several areas of plant cell biology (Tyerman, 1992; Hedrich, 1994;Schroeder, 1995). Salt loss from guard cells during stomatal closure and from euryhaline algae responding to hypoosmotic stress is effected principally by the opening of anion channels (Okazaki and Tazawa, 1990; Okazaki and Iwasaki, 1992; Schroeder et al., 1993; Schwartz et al., 1995). Thus, because the equilibrium potential of permeant anions is positive of 0 mV, the opening of anion channels depolarizes the membrane and brings the membrane potential into a range in which outward-rectifying K ϩ channels open to provide accompanying cation loss.A second important function of anion channels is likely to relate to the early stages of signal transduction. A wide range of stimuli, including fungal elicitors (Nü rnberger et al., 1994), red light (Ermolayeva et al., 1997, blue light (Cho and Spalding, 1996), and Nod factors (Ehrhardt et al., 1992), evoke a rapid depolarization of the plasma membrane, which, based on the measurements of fluxes, ionic currents, and inhibitor sensitivity, indicates the opening of anion channels. Ward et al. (1995) have proposed that one function of these anion-channel-evoked depolarizations might be to open voltage-dependent Ca 2ϩ channels, which, by allowing entry of external Ca 2ϩ , would elevate [Ca 2ϩ ] c . As befits these important roles in cell biology, the activities of anion channels are tightly regulated by voltage (Keller et al., 1989; Okihara et al

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“…However, the characteristics of these elevations cannot easily be controlled beyond altering the concentration of the agonist. We were aware of reports that the action potential produced by application of voltage is accompanied by an increase in intracellular calcium [Ca 2+ ] c in Chara spp (Williamson and Ashley, 1982) and that similar action potentials produced by voltage in higher plants can stimulate gene expression (Wildon et al, 1992;Herde et al, 1995). We therefore tested the hypothesis that application of voltage to Arabidopsis would cause an increase in [Ca 2+ ] c , which we could subsequently use to study calcium-regulated gene expression.…”

Section: Controlled Electrical Stimulations Elicit Specific Types Of mentioning

confidence: 99%

Transcriptomic Analysis Reveals Calcium Regulation of Specific Promoter Motifs inArabidopsis

et al. 2011

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Increases in intracellular calcium concentration ([Ca 2+ ] c ) mediate plant responses to stress by regulating the expression of genes encoding proteins that confer tolerance. Several plant stress genes have previously been shown to be calciumregulated, and in one case, a specific promoter motif Abscisic Acid Responsive-Element (ABRE) has been found to be regulated by calcium. A comprehensive survey of the Arabidopsis thaliana transcriptome for calcium-regulated promoter motifs was performed by measuring the expression of genes in Arabidopsis seedlings responding to three calcium elevations of different characteristics, using full genome microarray analysis. This work revealed a total of 269 genes upregulated by [Ca 2+ ] c in Arabidopsis. Bioinformatic analysis strongly indicated that at least four promoter motifs were [Ca 2+ ] c -regulated in planta. We confirmed this finding by expressing in plants chimeric gene constructs controlled exclusively by these cis-elements and by testing the necessity and sufficiency of calcium for their expression. Our data reveal that the C-Repeat/Drought-Responsive Element, Site II, and CAM box (along with the previously identified ABRE) promoter motifs are calcium-regulated. The identification of these promoter elements targeted by the second messenger intracellular calcium has implications for plant signaling in response to a variety of stimuli, including cold, drought, and biotic stress.

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Free Ca2+ and cytoplasmic streaming in the alga Chara

Cited by 424 publications

References 37 publications

Changes in Cell Ca2+ Distribution in Loquat Leaves and Its Effects on Cold Tolerance

Changes in Cell Ca2+ Distribution in Loquat Leaves and Its Effects on Cold Tolerance

Control of Cl− Efflux in Chara corallina by Cytosolic pH, Free Ca2+, and Phosphorylation Indicates a Role of Plasma Membrane Anion Channels in Cytosolic pH Regulation1

Transcriptomic Analysis Reveals Calcium Regulation of Specific Promoter Motifs inArabidopsis

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