Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

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

Abstract

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 CO2 and 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.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: The slac1 mutations impair CO 2 -, ABA- and dark-induced stomatal closure.
Figure 2: Tissue-specific expression and subcellular localization of SLAC1-family proteins.
Figure 3: Implication of SLAC1-family proteins in the maintenance of ion homeostasis across the plant plasma membranes.

References

  1. Hetherington, A. M. & Woodward, F. I. The role of stomata in sensing and driving environmental change. Nature 424, 901–908 (2003)

    Article  CAS  ADS  Google Scholar 

  2. Sellers, P. J. et al. Modeling the exchanges of energy, water, and carbon between continents and the atmosphere. Science 275, 502–509 (1997)

    Article  CAS  Google Scholar 

  3. Shaw, M. R. et al. Grassland responses to global environmental changes suppressed by elevated CO2 . Science 298, 1987–1990 (2002)

    Article  CAS  ADS  Google Scholar 

  4. MacRobbie, E. A. C. Signal transduction and ion channels in guard cells. Phil. Trans. R. Soc. Lond. B 353, 1475–1488 (1998)

    Article  CAS  Google Scholar 

  5. Hetherington, A. M. Guard cell signaling. Cell 107, 711–714 (2001)

    Article  CAS  Google Scholar 

  6. Schroeder, J. I. et al. Guard cell signal transduction. Annu. Rev. Plant Physiol. Plant Mol. Biol. 52, 627–658 (2001)

    Article  CAS  Google Scholar 

  7. Raschke, K., Shabahang, M. & Wolf, R. The slow and the quick anion conductance in whole guard cells: their voltage-dependent alternation, and the modulation of their activities by abscisic acid and CO2 . Planta 217, 639–650 (2003)

    Article  CAS  Google Scholar 

  8. Schroeder, J. I. & Hagiwara, S. Cytosolic calcium regulates ion channels in the plasma membrane of Vicia faba guard cells. Nature 338, 427–430 (1989)

    Article  ADS  Google Scholar 

  9. Willmer, C. M. & Fricker, M. D. Stomata 2nd edn (Chapman and Hall, London, 1996)

    Book  Google Scholar 

  10. Hashimoto, M. et al. Arabidopsis HT1 kinase controls stomatal movements in response to CO2 . Nature Cell Biol. 8, 391–397 (2006)

    Article  CAS  Google Scholar 

  11. Merlot, S. et al. Use of infrared thermal imaging to isolate Arabidopsis mutants defective in stomatal regulation. Plant J. 30, 601–609 (2002)

    Article  CAS  Google Scholar 

  12. Xie, X. D. et al. The identification of genes involved in the stomatal response to reduced atmospheric relative humidity. Curr. Biol. 16, 882–887 (2006)

    Article  CAS  Google Scholar 

  13. Negi, J., Hashimoto, M. & Iba, K. Characterization of CO2–insensitive Arabidopsis mutant cdi3. Plant Cell Physiol. 46, s176 (2005)

    Google Scholar 

  14. Vahisalu, T. et al. SLAC1 is required for plant guard cell S-type anion channel function in stomatal signalling. Nature (this issue) 10.1038/nature06608

  15. Uemura, T., Yoshimura, S., Takeyasu, K. & Sato, M. Vacuolar membrane dynamics revealed by GFP–AtVam3 fusion protein. Genes Cells 7, 743–753 (2002)

    Article  CAS  Google Scholar 

  16. Saier, M. H. et al. Phylogenetic characterization of novel transport protein families revealed by genome analyses. Biochim. Biophys. Acta 1422, 1–56 (1999)

    Article  CAS  Google Scholar 

  17. Grobler, J., Bauer, F., Subden, R. E. & van Vuuren, H. J. The mae1 gene of Schizosaccharomyces pombe encodes a permease for malate and other C4 dicarboxylic acids. Yeast 11, 1485–1491 (1995)

    Article  CAS  Google Scholar 

  18. Pfam database. 〈http://pfam.sanger.ac.uk/family?acc=PF03595〉 (2007)

  19. Vavasseur, A. & Raghavendra, A. Guard cell metabolism and CO2 sensing. New Phytol. 165, 665–682 (2005)

    Article  CAS  Google Scholar 

  20. Outlaw, D. et al. Requirements for activation of the signal-transduction network that leads to regulatory phosphorylation of leaf guard-cell phosphoenolpyruvate carboxylase during fusicoccin-stimulated stomatal opening. Arch. Biochem. Biophys. 407, 63–71 (2002)

    Article  CAS  Google Scholar 

  21. TMHMM Server v.2.0 〈http://www.cbs.dtu.dk/services/TMHMM/〉 (2007)

  22. De Angeli, A. et al. The nitrate/proton antiporter AtCLCa mediates nitrate accumulation in plant vacuoles. Nature 442, 939–942 (2006)

    Article  CAS  ADS  Google Scholar 

  23. Xu, J. et al. A protein kinase, interacting with two calcineurin B-like proteins, regulates K+ transporter AKT1 in Arabidopsis. Cell 125, 1347–1360 (2006)

    Article  CAS  Google Scholar 

  24. Ryan, P. R., Delhaize, E. & Jones, D. L. Function and mechanism of organic anion exudation from plant roots. Annu. Rev. Plant Physiol. Plant Mol. Biol. 52, 527–560 (2001)

    Article  CAS  Google Scholar 

  25. Köhler, B. & Raschke, K. The delivery of salts to the xylem. Three types of anion conductance in the plasmalemma of the xylem parenchyma of roots of barley. Plant Physiol. 122, 243–254 (2000)

    Article  Google Scholar 

  26. Clough, S. J. & Bent, A. F. Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant J. 16, 735–743 (1998)

    Article  CAS  Google Scholar 

  27. Mustilli, A. C., Merlot, S., Vavasseur, A., Fenzi, F. & Giraudat, J. Arabidopsis OST1 protein kinase mediates the regulation of stomatal aperture by abscisic acid and acts upstream of reactive oxygen species production. Plant Cell 14, 3089–3099 (2002)

    Article  CAS  Google Scholar 

  28. Inada, H. & Iba, K. in Photosynthesis: Mechanisms and Effects (ed. Garab, G.) 4 2999–3002 (Dordrecht, London, 1998)

  29. Chiu, W. et al. Engineered GFP as a vital reporter in plants. Curr. Biol. 6, 325–330 (1996)

    Article  CAS  Google Scholar 

  30. Dong, J., Kim, S. T. & Lord, E. M. Plantacyanin plays a role in reproduction in Arabidopsis. Plant Physiol. 138, 778–789 (2005)

    Article  CAS  Google Scholar 

  31. Hirata, N., Yonekura, D., Yanagisawa, S. & Iba, K. Possible involvement of the 5′-flanking region and the 5′UTR of plastid accD gene in NEP-dependent transcription. Plant Cell Physiol. 45, 176–186 (2004)

    Article  CAS  Google Scholar 

  32. Pandey, S., Wang, X. Q., Coursol, S. A. & Assmann, S. M. Preparation and applications of Arabidopsis thaliana guard cell protoplasts. New Phytol. 153, 517–526 (2002)

    Article  CAS  Google Scholar 

  33. Ueno, K. et al. Biochemical characterization of plasma membrane H+-ATPase activation in guard cell protoplasts of Arabidopsis thaliana in response to blue light. Plant Cell Physiol. 46, 955–963 (2005)

    Article  CAS  Google Scholar 

  34. Gotow, K. et al. Light activation of NADP-malate dehydrogenase in guard cell protoplasts from Vicia faba. Plant Physiol. 79, 829–832 (1985)

    Article  CAS  ADS  Google Scholar 

Download references

Acknowledgements

We thank M. H. Sato for providing the tonoplast control plants, I. C. Mori for technical advice, and N. Kawahara for technical assistance. This research was supported by a Core Research for Evolution and Technology (CREST)-type JST grant and a JSPS grant, and by the Ministry of Agriculture, Forestry and Fisheries of Japan (Rice Genome Project IP-5005) grants (K.I.). J.N. is the recipient of scholarships from JSPS and Nara Institute of Science and Technology (NAIST). M.H. is the JST post-doctoral fellow.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Koh Iba.

Additional information

Arabidopsis Genome Initiative (AGI) identifiers for SLAC1-family members are: SLAC1, At1g12480; SLAH1, At1g62280; SLAH2, At4g27970; and SLAH3, At5g24030.

Supplementary information

Supplementary Figures

The file contains Supplementary Figures S1-S5 with Legends. (PDF 577 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Negi, J., Matsuda, O., Nagasawa, T. et al. CO2 regulator SLAC1 and its homologues are essential for anion homeostasis in plant cells. Nature 452, 483–486 (2008). https://doi.org/10.1038/nature06720

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature06720

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing