Anion channel sensitivity to cytosolic organic acids implicates a central role for oxaloacetate in integrating ion flux with metabolism in stomatal guard cells

Wang, Y. and Blatt, M.R. (2011) Anion channel sensitivity to cytosolic organic acids implicates a central role for oxaloacetate in integrating ion flux with metabolism in stomatal guard cells. Biochemical Journal, 439(1), pp. 161-170. (doi: 10.1042/BJ20110845) (PMID:21745184) (PMCID:PMC3181827)

Abstract

Stomatal guard cells play a key role in gas exchange for photosynthesis and in minimizing transpirational water loss from plants by opening and closing the stomatal pore. The bulk of the osmotic content driving stomatal movements depends on ionic fluxes across both the plasma membrane and tonoplast, the metabolism of organic acids, primarily Mal (Imitate), and its accumulation and loss. Anion channels at the plasma membrane are thought to comprise a major pathway for Mal efflux during stomatal closure, implicating their key role in linking solute flux with metabolism. Nonetheless, little is known of the regulation of anion channel current (I(Cl)) by cytosolic Mal or its immediate metabolite OAA (oxaloacetate). In the present study, we have examined the impact of Mal, OAA and of the monocarboxylic acid anion acetate in guard cells of Vicia faba L. and report that all three organic acids affect I(Cl), but with markedly different characteristics and sidedness to their activities. Most prominent was a suppression of I(Cl) by OAA within the physiological range of concentrations found in vivo. These findings indicate a capacity for OAA to co-ordinate organic acid metabolism with I(Cl), through the direct effect of organic acid pool size. The findings of the present study also add perspective to in vivo recordings using acetate-based electrolytes.

• Item Type: Articles
• Additional Information: The author(s) has paid for this article to be freely available under the terms of the Creative Commons Attribution Non-Commercial Licence which permits unrestricted non-commercial use, distribution and reproduction in any medium, provided the original work is properly cited.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Blatt, Professor Michael
• Authors: Wang, Y., and Blatt, M.R.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Biochemical Journal
• Publisher: Biochemical Society
• ISSN: 0264-6021
• Published Online: 11 July 2011
• Copyright Holders: Copyright © 2011 The Authors
• First Published: First published in Biochemical Journal 439(1):161-170
• Publisher Policy: Reproduced under a Creative Commons Licence

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
45256	2	Analysis of membrane traffic in adaptive stress tolerance in plants	Michael Blatt	Biotechnology and Biological Sciences Research Council (BBSRC)	BB/F001630/1	Institute of Molecular Cell and Systems Biology