Systems analysis of guard cell oscillatory mechanics in stomatal dynamics

气孔动力学中保卫细胞振荡力学的系统分析

• 批准号: BB/F001177/1
• 负责人: Alistair Hetherington
• 金额: $ 26.81万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FF001177%2F1
• 关键词: Systems; analysis; guard; cell; oscillatory

Stomata in the epidermis of plant leaves play a vital role in regulating CO2 exchange for photosynthesis while minimising transpirational water loss between the inner leaf air space and the atmosphere. Guard cells surrounding the stomata take up inorganic solutes and water, increasing in volume to open the stomatal pore when CO2 in the leaf is depleted; and they lose solutes and water, decreasing in volume to close the stomatal pore and conserve leaf water under stress, in the dark and when CO2 is high. We know a great deal about the mechanisms that drive stomatal movements between the extremes in pore aperture. By contrast, our knowledge is remarkably poor of the mechanisms that give rise to the dynamic continuum of apertures normally observed in the field, much less how such fine-tuning is regulated. This gap in knowledge can be seen, for example, in the focus of past efforts in quantitative modelling. Stomatal characteristics underpin models for transpiration and plant water use efficiency that have proven successful in reproducing and predicting transpirational behaviours at the plant and community levels. However all of these models reflect a 'top-down' approach and consider guard cell mechanics as a 'black box', subsuming these processes within a few empirical parameters, hydraulic pathways and conductances. There are very few models that have been developed 'bottom-up' from the properties of the guard cells themselves, despite the wealth of knowledge we have for guard cell transport and signalling, and none that are sufficiently generalised to be widely applicable in predicting stomatal behaviour. A further complication is that much of our knowledge at the cellular level is based on in vitro studies with guard cells in epidermal peels or isolated as protoplasts. We need to bridge these gaps in our knowledge and to understand how stomata compensate dynamically in the face of real environmental challenges. Studies over the past 15 years have yielded several important clues to the mechanisms behind stomatal dynamics. The clues point to oscillations of the guard cell membrane between two quasi-stable states that control and balance osmotic fluxes. This postulate finds support in well-documented observations that stomatal apertures also oscillate and can be driven experimentally under defined conditions. Indeed, such a 'time-averaging' mechanism has already been predicted from a systems analysis of guard cell ion transport, albeit using a mathematical model with significant parameter limitations. These several lines of evidence need now to be drawn together and subject to rigorous experimental testing in order to address a number of key issues. We need to know whether more comprehensive mathematical models for guard cell transport / incorporating, for example, known regulatory properties for the major ion transporters / are able to return the full range of observed behaviours in aperture and voltage, and to predict novel ones. We want to know how these behaviours are underpinned by the dynamics of guard cell ion fluxes and osmotic contents. Finally, we want to test whether experimental manipulations of the relevant guard cell parameters can be shown to yield well-defined and predictable changes in stomatal behaviour. We propose here to develop this line of enquiry jointly through systems kinetic modelling to derive quantitative and testable predictions and through experimental analysis and validation. Our knowledge of guard cell transport and homeostasis is now sufficiently well-developed to make an approach of this kind a readily achievable goal. We fully expect answers to the questions we pose to yield new and exciting insights into the behaviour of stomata and to open entirely new dimensions to practical applications in agriculture and crop development.

植物叶片表皮中的气孔在调节光合作用的CO2交换中起着至关重要的作用，同时最大限度地减少内部叶片空气空间和大气之间的蒸腾水分损失。气孔周围的保卫细胞吸收无机溶质和水，当叶片中的CO2耗尽时，体积增加以打开气孔;并且它们失去溶质和水，在黑暗和CO2高的胁迫下，体积减少以关闭气孔并保存叶片水分。我们知道很多关于气孔运动的机制之间的极端孔隙。相比之下，我们的知识是显着贫穷的机制，产生了动态连续的光圈通常在现场观察到，更不用说这种微调是如何调节。例如，从过去定量建模工作的重点可以看出这一知识差距。气孔特征支持蒸腾和植物水分利用效率的模型，这些模型已被证明在植物和群落水平上成功地再现和预测蒸腾行为。然而，所有这些模型都反映了一个“自上而下”的方法，并考虑警卫细胞力学作为一个“黑箱”，这些过程包含在几个经验参数，液压通路和电导。有很少的模型，已开发的“自下而上”的保卫细胞本身的属性，尽管我们有丰富的知识，保卫细胞的运输和信号，并没有足够的概括，广泛适用于预测气孔行为。更复杂的是，我们在细胞水平上的许多知识都是基于对表皮表皮中的保卫细胞或分离为原生质体的保卫细胞的体外研究。我们需要填补知识上的这些空白，了解气孔在面对真实的环境挑战时如何动态补偿。过去15年的研究已经为气孔动力学机制提供了一些重要线索。这些线索指向保卫细胞膜在两个准稳定状态之间的振荡，这两个准稳定状态控制和平衡渗透通量。这一假设在有据可查的观察中得到了支持，即气孔孔径也会振荡，并且可以在定义的条件下通过实验驱动。事实上，这样的“时间平均”机制已经从保护细胞离子传输的系统分析中预测，尽管使用具有显著参数限制的数学模型。这几条证据现在需要汇集在一起，并接受严格的实验测试，以解决一些关键问题。我们需要知道是否更全面的数学模型的保护细胞运输/纳入，例如，已知的监管性质的主要离子转运蛋白/能够返回的孔径和电压的观察到的行为的全部范围，并预测新的。我们想知道这些行为是如何由保卫细胞离子通量和渗透内容物的动态支持的。最后，我们要测试是否实验操作相关的保卫细胞参数可以显示出良好的定义和可预测的气孔行为的变化。在这里，我们建议通过系统动力学建模，以获得定量和可测试的预测，并通过实验分析和验证，共同开发这条调查线。我们对保卫细胞运输和体内平衡的了解现在已经足够发达，使这种方法成为一个容易实现的目标。我们完全期待我们提出的问题的答案，以产生新的和令人兴奋的见解气孔的行为，并打开全新的层面，在农业和作物发展的实际应用。

项目成果

Control of vacuolar dynamics and regulation of stomatal aperture by tonoplast potassium uptake

• DOI: 10.1073/pnas.1320421111
• 发表时间: 2014-04-29
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Andres, Zaida;Perez-Hormaeche, Javier;Pardo, Jose M.
• 通讯作者: Pardo, Jose M.

Actin filament reorganisation controlled by the SCAR/WAVE complex mediates stomatal response to darkness.

由 SCAR/WAVE 复合物控制的肌动蛋白丝重组介导气孔对黑暗的反应

• DOI: 10.1111/nph.14655
• 发表时间: 2017-08
• 期刊: The New phytologist
• 作者: Isner JC;Xu Z;Costa JM;Monnet F;Batstone T;Ou X;Deeks MJ;Genty B;Jiang K;Hetherington AM
• 通讯作者: Hetherington AM

A stress-specific calcium signature regulating an ozone-responsive gene expression network in Arabidopsis.

• DOI: 10.1111/j.1365-313x.2012.05043.x
• 发表时间: 2012-09
• 期刊: The Plant journal : for cell and molecular biology
• 作者: E. Short;K. A. North;M. Roberts;A. Hetherington;A. Shirras;M. McAinsh