Sphingosine-1-phosphate and stomata


Drought-induced guard cell signal transduction involves sphingosine-1-phosphate.

Ng C. K. Y., Carr K., McAinsh M. R., Powell B., Hetherington A. M. (2001)

Carl K.-Y. Ng1, Kathryn Carr2, Martin R. McAinsh1, Brian Powell2 & Alistair M. Hetherington1

  1. Department of Biological Sciences, Institute of Environmental and Natural Sciences, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK
  2. Avecia Limited, Hexagon House, Blackley, Manchester M9 8ZS, UK


in Nature 410, 596–599. – doi: 10.1038/35069092 –

PubMed Abstract | CrossRef Full Text | Google Scholar – 



Stomata form pores on leaf surfaces that regulate the uptake of CO2 for photosynthesis and the loss of water vapour during transpiration1. An increase in the cytosolic concentration of free calcium ions ([Ca2+]cyt) is a common intermediate in many of the pathways leading to either opening or closure of the stomatal pore2, 3.

This observation has prompted investigations into how specificity is controlled in calcium-based signalling systems in plants. One possible explanation is that each stimulus generates a unique increase in [Ca2+]cyt, or ‘calcium signature’, that dictates the outcome of the final response4.

It has been suggested that the key to generating a calcium signature, and hence to understanding how specificity is controlled, is the ability to access differentially the cellular machinery controlling calcium influx and release from internal stores2, 3, 4, 5 .

Here we report that sphingosine-1-phosphate is a new calcium-mobilizing molecule in plants. We show that after drought treatment sphingosine-1-phosphate levels increase, and we present evidence that this molecule is involved in the signal-transduction pathway linking the perception of abscisic acid to reductions in guard cell turgor.


ABA signaling in stomata and nitric oxide


Nitric oxide is a novel component of abscisic acid signaling in stomatal guard cells.

by Neill S. J., Desikan R., Clarke A., Hancock J. T. (2002)

  1. Steven J. Neill
  2. Radhika Desikan
  3. Andrew Clarke
  4. John T. Hancock

Centre for Research in Plant Science, University of the West of England, Bristol, Coldharbour Lane, Bristol BS16 1QY, United Kingdom


in Plant Physiology 128, 13-16. – doi: http://dx.doi.org/10.1104/pp.010707 – 

CrossRef | CAS | PubMed | FREE Full Text – PubMed Abstract | CrossRef Full Text | Google Scholar – 



Stomatal closure in response to the hormone abscisic acid (ABA) is mediated by a complex signaling network involving both calcium-dependent and calcium-independent pathways (Assmann and Shimazaki, 1999; Webb et al., 2001), activated by several signaling intermediates (Schroeder et al., 2001) that include hydrogen peroxide (Miao et al., 2000; Pei et al., 2000;Zhang et al., 2001) and lipids such as sphingosine-1-phosphate (Ng et al., 2001).

Here, we provide evidence that nitric oxide (NO) is also a signaling component of ABA-induced stomatal closure.

Our data show that NO synthesis is required for ABA-induced closure and that ABA enhances NO synthesis in guard cells.

Exogenous NO induces stomatal closure, and ABA and NO-induced closure require the synthesis and action of cGMP and cyclic ADP Rib (cADPR).


Engineering stomatal responses to control CO2 intake and plant water loss.


Guard cell abscisic acid signaling and engineering drought hardiness in plants.

by Schroeder J. I., Kwak J. M., Allen G. J. (2001)

Julian I. Schroeder, June M. Kwak, Gethyn J. Allen

in Nature 410, 327–330. – doi: 10.1038/35066500 –

PubMed Abstract | CrossRef Full Text | Google ScholarMedline, – 



Guard cells are located in the epidermis of plant leaves, and in pairs surround stomatal pores. These control both the influx of CO2 as a raw material for photosynthesis and water loss from plants through transpiration to the atmosphere.

Guard cells have become a highly developed system for dissecting early signal transduction mechanisms in plants. In response to drought, plants synthesize the hormone abscisic acid, which triggers closing of stomata, thus reducing water loss.

Recently, central regulators of guard cell abscisic acid signalling have been discovered. The molecular understanding of the guard cell signal transduction network opens possibilities for engineering stomatal responses to control CO2 intake and plant water loss.

CO2 regulator SLAC1 and its homologues in stomata


CO2 regulator SLAC1 and its homologues are essential for anion homeostasis in plant cells.

by Negi J.Matsuda O.Nagasawa T.Oba Y.Takahashi H.Kawai-Yamada M.Uchimiya H.Hashimoto M.Iba K. (2008)

Juntaro Negi1, Osamu Matsuda1, Takashi Nagasawa1, Yasuhiro Oba1, Hideyuki Takahashi2, Maki Kawai-Yamada3, Hirofumi Uchimiya2,3, Mimi Hashimoto1 & Koh Iba1

  1. Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
  2. Iwate Biotechnology Center, Kitakami, Iwate 024-0003, Japan
  3. Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo 113-0032, Japan

in Nature 452: 483486 – doi: 10.1038/nature06720 –

Pubmed Abstract | Pubmed Full Text | CrossRef Full Text | Google Scholar – Medline– 



The continuing rise in atmospheric [CO2] is predicted to have diverse and dramatic effects on the productivity of agriculture, plant ecosystems and gas exchange1, 2, 3.

Stomatal pores in the epidermis provide gates for the exchange of CO2and water between plants and the atmosphere, processes vital to plant life4, 5, 6. Increased [CO2] has been shown to enhance anion channel activity7 proposed to mediate efflux of osmoregulatory anions (Cl and malate2–) from guard cells during stomatal closure8, 9.

However, the genes encoding anion efflux channels in plant plasma membranes remain unknown.

Here we report the isolation of an Arabidopsis gene, SLAC1 (SLOW ANION CHANNEL-ASSOCIATED 1, At1g12480), which mediates CO2 sensitivity in regulation of plant gas exchange. The SLAC1 protein is a distant homologue of bacterial and fungal C4-dicarboxylate transporters, and is localized specifically to the plasma membrane of guard cells.

It belongs to a protein family that in Arabidopsis consists of four structurally related members that are common in their plasma membrane localization, but show distinct tissue-specific expression patterns.

The loss-of-function mutation in SLAC1 was accompanied by an over-accumulation of the osmoregulatory anions in guard cell protoplasts. Guard-cell-specific expression of SLAC1 or its family members resulted in restoration of the wild-type stomatal responses, including CO2 sensitivity, and also in the dissipation of the over-accumulated anions.

These results suggest that SLAC1-family proteins have an evolutionarily conserved function that is required for the maintenance of organic/inorganic anion homeostasis on the cellular level.

Stomata and sensing or preventing xylem cavitation


Limitation of stomatal conductance by hydraulic traits: sensing or preventing xylem cavitation?

by Nardini A., Salleo S. (2000)

  • Andrea Nardini
  • Sebastiano Salleo

in Trees 15, 14–24 (2000). doi:10.1007/s004680000071 –



We tested the hypothesis that hydraulic conductance per unit leaf surface area of plant shoots (KSL) determines the maximum diurnal stomatal conductance (gL) that can be reached by plants growing in the field.

A second hypothesis was tested that some xylem cavitation cannot be avoided by transpiring plants and might act as a signal for regulating gL.

Eleven woody species were studied, differing from each other with respect to taxonomy, wood anatomy and leaf habit. Maximum diurnal gL, transpiration rate (EL), pre-dawn and minimum diurnal leaf water potential (Ψpd and Ψmin, respectively) were measured in the field. The critical Ψ level at which stem cavitation was triggered (Ψcav) was measured on detached branches, using the acoustic method. A high-pressure flow meter was used to measure maximum KSL of 1-year-old shoots.

Both gL and EL were positively related to KSL. The whole-plant hydraulic conductance per unit leaf area (KWL) of all the species studied, calculated as the ratio of EL to ΔΨ (=<I>Ψ</I><SUB>pd</SUB>-<I>Ψ</I><SUB>min</SUB>) was closely related to KSL. In every case, Ψmin (ranging between –0.85 and –1.35 MPa in the different species) dropped to the Ψcav range or was <Ψcav (ranging between –0.71 and –1.23 MPa), thus suggesting that some cavitation-induced embolism could not be avoided.

The possibility is discussed that some cavitation-induced reduction in KSL is the signal for stomatal closure preventing runaway embolism. The lack of correlation of gL to Ψcav is discussed in terms of the inconsistency of Ψcav as an indicator of the vulnerability of plants to cavitation.

No differences in hydraulic traits were observed between evergreen and deciduous species.

CPK13 reduces stomatal aperture through its inhibition of the guard cell-expressed KAT2 and KAT1 channels.


CPK13, a noncanonical Ca2+-dependent protein kinase, specifically inhibits KAT2 and KAT1 shaker K+ channels and reduces stomatal opening.

by Ronzier E.Corratgé-Faillie C.Sanchez F.Prado K.Brière C.Leonhardt N.Thibaud J. B.Xiong T. C. (2014)

  1. Elsa Ronzier,
  2. Claire Corratgé-Faillie,
  3. Frédéric Sanchez,
  4. Karine Prado,
  5. Christian Brière,
  6. Nathalie Leonhardt,
  7. Jean-Baptiste Thibaud
  8. Tou Cheu Xiong
  1. Institut National de la Recherche Agronomique, Unité Mixte de Recherche 386, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5004, SupAgro, and Université Montpellier 2, Laboratoire de Biochimie & Physiologie Moléculaire des Plantes, F–34060 Montpellier cedex 2, France (E.R., C.C.-F., F.S., K.P., J.-B.T., T.C.X.);

  2. Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5546, Laboratoire de Recherche en Sciences Végétales, 31326 Castanet-Tolosan, France (C.B.);

  3. Université Paul Sabatier, Pôle de Biotechnologies Végétales 24, Chemin de Borde Rouge, Boite Postale 42617 Auzeville, 31326 Castanet-Tolosan, France (C.B.); and

  4. Laboratoire de Biologie du Développement des Plantes, Unité Mixte de Recherche 7265 Centre National de la Recherche Scientifique-Commissariat à l’Energie Atomique-Université Aix-Marseille II, Commissariat à l’Energie Atomique Cadarache Bat 156, 13108 St. Paul Lez Durance, France (N.L.)

in Plant Physiol. 166: 314326 – doi: http://dx.doi.org/10.1104/pp.114.240226

Abstract/FREE Full Text – 



Ca2+-dependent protein kinases (CPKs) form a large family of 34 genes in Arabidopsis (Arabidopsis thaliana).

Based on their dependence on Ca2+, CPKs can be sorted into three types: strictly Ca2+-dependent CPKs, Ca2+-stimulated CPKs (with a significant basal activity in the absence of Ca2+), and essentially calcium-insensitive CPKs.

Here, we report on the third type of CPK, CPK13, which is expressed in guard cells but whose role is still unknown. We confirm the expression of CPK13 in Arabidopsis guard cells, and we show that its overexpression inhibits light-induced stomatal opening.

We combine several approaches to identify a guard cell-expressed target. We provide evidence that CPK13

(1) specifically phosphorylates peptide arrays featuring Arabidopsis K+ Channel KAT2 and KAT1 polypeptides,

(2) inhibits KAT2 and/or KAT1 when expressed in Xenopus laevis oocytes, and

(3) closely interacts in plant cells with KAT2 channels (Förster resonance energy transfer-fluorescence lifetime imaging microscopy).

We propose that CPK13 reduces stomatal aperture through its inhibition of the guard cell-expressed KAT2 and KAT1 channels.

A potassium channel gene in stomata


Expression of an Arabidopsis potassium channel gene in guard cells.

by Nakamura R. L., McKendree W. L., Hirsch R. E., Sedbrook J. C., Gaber R. F., Sussman M. R. (1995)

  1. R. L. Nakamura,
  2. W. L. McKendree Jr,
  3. R. E. Hirsch,
  4. J. C. Sedbrook,
  5. R. F. Gaber
  6. M. R. Sussman

Program in Cell and Molecular Biology and Department of Horticulture, 1575 Linden Drive (W.L.M., R.E.H., M.R.S.)


in Plant Physiology 109, 371–374. – doi: http://dx.doi.org/10.1104/pp.109.2.371 – 

Abstract – 



The Arabidopsis thaliana KAT1 cDNA encodes a voltage-gated inward-rectifying K+ channel. A KAT1 genomic DNA clone was isolated and sequenced, and a 5[prime] promoter and coding sequences containing eight introns were identified.

Reporter gene analysis of transgenic plants containing the KAT1 promoter fused to bacterial [beta]-glucuronidase showed robust [beta]-glucuronidase activity primarily in guard cells.