Systems dynamic modeling of the stomatal guard cell predicts emergent behaviors in transport, signaling, and volume control

Chen, Z.-H., Hills, A., Batz, U., Amtmann, A. , Lew, V.L. and Blatt, M.R. (2012) Systems dynamic modeling of the stomatal guard cell predicts emergent behaviors in transport, signaling, and volume control. Plant Physiology, 159(3), pp. 1235-1251. (doi: 10.1104/pp.112.197350)

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Abstract

The dynamics of stomatal movements and their consequences for photosynthesis and transpirational water loss have long been incorporated into mathematical models, but none have been developed from the bottom up that are widely applicable in predicting stomatal behavior at a cellular level. We previously established a systems dynamic model incorporating explicitly the wealth of biophysical and kinetic knowledge available for guard cell transport, signaling, and homeostasis. Here we describe the behavior of the model in response to experimentally documented changes in primary pump activities and malate (Mal) synthesis imposed over a diurnal cycle. We show that the model successfully recapitulates the cyclic variations in H(+), K(+), Cl(-), and Mal concentrations in the cytosol and vacuole known for guard cells. It also yields a number of unexpected and counterintuitive outputs. Among these, we report a diurnal elevation in cytosolic-free Ca(2+) concentration and an exchange of vacuolar Cl(-) with Mal, both of which find substantiation in the literature but had previously been suggested to require additional and complex levels of regulation. These findings highlight the true predictive power of the OnGuard model in providing a framework for systems analysis of stomatal guard cells, and they demonstrate the utility of the OnGuard software and HoTSig library in exploring fundamental problems in cellular physiology and homeostasis.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hills, Mr Adrian and Blatt, Professor Michael and Amtmann, Professor Anna
Authors: Chen, Z.-H., Hills, A., Batz, U., Amtmann, A., Lew, V.L., and Blatt, M.R.
College/School:College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
Journal Name:Plant Physiology
ISSN:0032-0889
ISSN (Online):1532-2548
Published Online:01 May 2012

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