Skip to main content
PMC home page
Plant Physiology logoLink to Plant Physiology
. 1995 Oct;109(2):549–556. doi: 10.1104/pp.109.2.549

Tonoplast Na+/H+ Antiport Activity and Its Energization by the Vacuolar H+-ATPase in the Halophytic Plant Mesembryanthemum crystallinum L.

B J Barkla 1, L Zingarelli 1, E Blumwald 1, JAC Smith 1
PMCID: PMC157619  PMID: 12228611

Abstract

Tonoplast vesicles were isolated from leaf mesophyll tissue of the inducible Crassulacean acid metabolism plant Mesembryanthemum crystallinum to investigate the mechanism of vacuolar Na+ accumulation in this halophilic species. In 8-week-old plants exposed to 200 mM NaCl for 2 weeks, tonoplast H+-ATPase activity was approximately doubled compared with control plants of the same age, as determined by rates of both ATP hydrolysis and ATP-dependent H+ transport. Evidence was also obtained for the presence of an electroneutral Na+/H+ antiporter at the tonoplast that is constitutively expressed, since extravesicular Na+ was able to dissipate a pre-existing transmembrane pH gradient. Initial rates of H+ efflux showed saturation kinetics with respect to extravesicular Na+ concentration and were 2.1-fold higher from vesicles of salt-treated plants compared with the controls. Na+-dependent H+ efflux also showed a high selectivity for Na+ over K+, was insensitive to the transmembrane electrical potential difference, and was more than 50% inhibited by 200 [mu]M N-amidino-3,5-diamino-6-chloropyrazinecarboxamide hydrochloride. The close correlation between increased Na+/H+ antiport and H+-ATPase activities in response to salt treatment suggests that accumulation of the very high concentrations of vacuolar Na+ found in M. crystallinum is energized by the H+ electrochemical gradient across the tonoplast.

Full Text

The Full Text of this article is available as a PDF (898.8 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Barkla B. J., Blumwald E. Identification of a 170-kDa protein associated with the vacuolar Na+/H+ antiport of Beta vulgaris. Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):11177–11181. doi: 10.1073/pnas.88.24.11177. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Barkla B. J., Charuk J. H., Cragoe E. J., Blumwald E. Photolabeling of tonoplast from sugar beet cell suspensions by [h]5-(N-methyl-N-isobutyl)-amiloride, an inhibitor of the vacuolar na/h antiport. Plant Physiol. 1990 Jul;93(3):924–930. doi: 10.1104/pp.93.3.924. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Blumwald E., Poole R. J. Salt tolerance in suspension cultures of sugar beet : induction of na/h antiport activity at the tonoplast by growth in salt. Plant Physiol. 1987 Apr;83(4):884–887. doi: 10.1104/pp.83.4.884. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bowman E. J., Siebers A., Altendorf K. Bafilomycins: a class of inhibitors of membrane ATPases from microorganisms, animal cells, and plant cells. Proc Natl Acad Sci U S A. 1988 Nov;85(21):7972–7976. doi: 10.1073/pnas.85.21.7972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1006/abio.1976.9999. [DOI] [PubMed] [Google Scholar]
  6. Cushman J. C., Michalowski C. B., Bohnert H. J. Developmental control of crassulacean Acid metabolism inducibility by salt stress in the common ice plant. Plant Physiol. 1990 Nov;94(3):1137–1142. doi: 10.1104/pp.94.3.1137. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Garbarino J., Dupont F. M. NaCl Induces a Na/H Antiport in Tonoplast Vesicles from Barley Roots. Plant Physiol. 1988 Jan;86(1):231–236. doi: 10.1104/pp.86.1.231. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Garbarino J., Dupont F. M. Rapid induction of na/h exchange activity in barley root tonoplast. Plant Physiol. 1989 Jan;89(1):1–4. doi: 10.1104/pp.89.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Guern J., Mathieu Y., Kurkdjian A., Manigault P., Manigault J., Gillet B., Beloeil J. C., Lallemand J. Y. Regulation of Vacuolar pH of Plant Cells: II. A P NMR Study of the Modifications of Vacuolar pH in Isolated Vacuoles Induced by Proton Pumping and Cation/H Exchanges. Plant Physiol. 1989 Jan;89(1):27–36. doi: 10.1104/pp.89.1.27. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Matoh T., Ishikawa T., Takahashi E. Collapse of ATP-Induced pH Gradient by Sodium Ions in Microsomal Membrane Vesicles Prepared from Atriplex gmelini Leaves: Possibility of Na/H Antiport. Plant Physiol. 1989 Jan;89(1):180–183. doi: 10.1104/pp.89.1.180. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Reuveni M., Bennett A. B., Bressan R. A., Hasegawa P. M. Enhanced H Transport Capacity and ATP Hydrolysis Activity of the Tonoplast H-ATPase after NaCl Adaptation. Plant Physiol. 1990 Oct;94(2):524–530. doi: 10.1104/pp.94.2.524. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Sze H, Ward JM, Lai S, Perera I., I VACUOLAR-TYPE H+-TRANSLOCATING ATPases IN PLANT ENDOMEMBRANES: SUBUNIT ORGANIZATION AND MULTIGENE FAMILIES. J Exp Biol. 1992 Nov 1;172(Pt 1):123–135. doi: 10.1242/jeb.172.1.123. [DOI] [PubMed] [Google Scholar]
  13. White P. J., Marshall J., Smith J. A. Substrate kinetics of the tonoplast h-translocating inorganic pyrophosphatase and its activation by free mg. Plant Physiol. 1990 Jul;93(3):1063–1070. doi: 10.1104/pp.93.3.1063. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES