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Guard cell endomembrane Ca2+-ATPases underpin a ‘carbon memory’ of photosynthetic assimilation that impacts on water-use efficiency

Jezek, Mareike and Silva-Alvim, Fernanda AL and Hills, Adrian and Donald, Naomi and Ishka, Maryam Rahmati and Shadbolt, Jessica and He, Bingqing and Lawson, Tracy and Harper, Jeffrey F and Wang, Yizhou and Lew, Virgilio L and Blatt, Michael R (2021) 'Guard cell endomembrane Ca2+-ATPases underpin a ‘carbon memory’ of photosynthetic assimilation that impacts on water-use efficiency.' Nature Plants. ISSN 2055-026X

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Abstract

Stomata of most plants close to preserve water when the demand for CO2 by photosynthesis is reduced. Stomatal responses are slow compared with photosynthesis, and this kinetic difference erodes assimilation and water-use efficiency under fluctuating light. Despite a deep knowledge of guard cells that regulate the stoma, efforts to enhance stomatal kinetics are limited by our understanding of its control by foliar CO2. Guided by mechanistic modelling that incorporates foliar CO2 diffusion and mesophyll photosynthesis, here we uncover a central role for endomembrane Ca2+ stores in guard cell responsiveness to fluctuating light and CO2. Modelling predicted and experiments demonstrated a delay in Ca2+ cycling that was enhanced by endomembrane Ca2+-ATPase mutants, altering stomatal conductance and reducing assimilation and water-use efficiency. Our findings illustrate the power of modelling to bridge the gap from the guard cell to whole-plant photosynthesis, and they demonstrate an unforeseen latency, or ‘carbon memory’, of guard cells that affects stomatal dynamics, photosynthesis and water-use efficiency.

Item Type: Article
Divisions: Faculty of Science and Health > Life Sciences, School of
Depositing User: Elements
Date Deposited: 10 Aug 2021 08:33
Last Modified: 10 Aug 2021 08:33
URI: http://repository.essex.ac.uk/id/eprint/30865

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