Guard cell endomembrane Ca2+-ATPases underpin a 'carbon memory' of photosynthetic assimilation that impacts on water-use efficiency
Guard cell endomembrane Ca2+-ATPases underpin a 'carbon memory' of photosynthetic assimilation that impacts on water-use efficiency
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保卫细胞内膜Ca2+-ATP酶支撑光合同化的“碳记忆”，影响水分利用效率
DOI：
10.1038/s41477-021-00966-2
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发表时间：
2021-07-29
期刊：
影响因子：
18
通讯作者：
Blatt, Michael R.
中科院分区：
文献类型：
--
作者：
Jezek, Mareike;Silva-Alvim, Fernanda A. L.;Blatt, Michael R.
当光合作用对二氧化碳的需求减少时，大多数植物的气孔会接近保存水分。与光合作用相比，气孔反应缓慢，这种动力学差异会削弱波动光下的同化和水分利用效率。尽管对调节气孔的保卫细胞有深入的了解，但我们对叶面二氧化碳控制的理解限制了增强气孔动力学的努力。在结合叶面二氧化碳扩散和叶肉光合作用的机械模型的指导下，我们揭示了内膜 Ca2+ 储存在保卫细胞对波动光和二氧化碳的响应中的核心作用。模型预测和实验表明，内膜 Ca2+-ATPase 突变体会增强 Ca2+ 循环的延迟，从而改变气孔导度并降低同化和水分利用效率。我们的研究结果说明了建模的力量，可以弥补保卫细胞与全植物光合作用之间的差距，并且证明了保卫细胞的不可预见的潜伏期或“碳记忆”会影响气孔动力学、光合作用和水分利用效率。
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.