Analysing GORK clustering for enhanced stomatal control

分析 GORK 聚类以增强气孔控制

• 批准号: BB/M001601/1
• 负责人: Michael Blatt
• 金额: $ 57.06万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FM001601%2F1
• 关键词: Analysing; GORK; clustering; enhanced; stomatal

Stomata are pores that provide for gaseous exchange across the impermeable cuticle of plant leaves. They open and close to balance the requirement for CO2 entry for photosynthesis against the need to reduce the transpiration of water vapour and prevent leaf drying. Stomatal transpiration is at the centre of a crisis in water availability and crop production that is expected to unfold over the next 20-30 years: globally, agricultural water usage has increased 6-fold in the past 100 years, twice as fast as the human population, and is projected to double again before 2030. The bulk of water used in agriculture passes through the stomatal pore. Thus stomata represent an important target for manipulating crop performance. Significantly, stomatal responses are often delayed in the face of environmental fluctuations, especially of light. Improving water use efficiency (=amount of carbon fixed in photosynthesis/amount of water transpired) should be possible, without a cost to carbon assimilated in photosynthesis, if the speed of stomatal response can be enhanced.Stomatal movements are driven by solute transport - and consequent uptake/loss of water - across the cell membrane of the guard cells which surround the stomatal pore. Guard cells harbour ion channel proteins to facilitate cation flux for stomatal movement. Uniquely, the opening (or gating) of one class of plant ion channels is also sensitive to external K+ concentration. These channels are found in guard cells of tobacco, Vicia and Arabidopsis, in the latter encoded solely by the GORK gene. Increasing K+ outside moderates channel opening in parallel with the equilibrium voltage for K+ and affects whole-cell conductance. These channels are the main pathway for K+ efflux during stomatal closure, but their K+-sensitivity constrains K+ flux capacity, notably at higher external K+. Estimates based on recent modelling suggests that stomatal closure could be accelerated 3-fold with only a moderate increase in the flux capacity of these channels.The K+-sensitivity of the GORK channel is a property of the channel protein itself, which should facilitate manipulating K+ efflux capacity to accelerate stomatal closure. My laboratory has uncovered evidence that the K+-dependence of GORK gating is associated with its assembly in clusters. These assemblies require the the so-called 'voltage-sensor domains' (VSDs) of GORK to interact with one another. Movement of the VSDs is known to couple voltage to channel gating, so it is likely that interaction between VSDs provides a mechanism for cooperative self-regulation. I propose now to complete the analysis of GORK VSD interaction and the consequences for channel control and for stomatal movements. Regardless of the mechanism, it is clear that these discoveries offer the means to explore a unique and fundamental property of this class of K+ channels in plants and to manipulate channel activity, potentially enhancing the kinetics of stomatal closure and water use by the plant.

气孔是在植物叶子的不渗透角质层之间提供气体交换的孔隙。它们的打开和关闭是为了平衡光合作用二氧化碳进入的需要与减少水蒸气蒸腾和防止叶子干燥的需要。气孔蒸腾是水资源供应和农作物生产危机的核心，预计这一危机将在未来 20-30 年内展开：全球范围内，农业用水量在过去 100 年中增加了 6 倍，是人类用水速度的两倍人口，预计到 2030 年将再次翻倍。农业用水的大部分通过气孔。因此，气孔代表了操纵作物性能的重要目标。值得注意的是，面对环境波动，尤其是光的波动，气孔反应通常会延迟。如果可以提高气孔响应速度，则应该可以提高水分利用效率（=光合作用中固定的碳量/蒸腾的水量），而不需要光合作用中碳同化的成本。气孔运动是由溶质运输驱动的 - 和随后的水吸收/损失 - 穿过气孔周围的保卫细胞的细胞膜。保卫细胞含有离子通道蛋白，以促进气孔运动的阳离子通量。独特的是，一类植物离子通道的开放（或门控）也对外部 K+ 浓度敏感。这些通道存在于烟草、蚕豆和拟南芥的保卫细胞中，后者仅由 GORK 基因编码。增加外部 K+ 会与 K+ 的平衡电压同时缓和通道开放，并影响全细胞电导。这些通道是气孔关闭期间 K+ 流出的主要途径，但它们的 K+ 敏感性限制了 K+ 通量能力，特别是在较高的外部 K+ 情况下。基于最近模型的估计表明，只要这些通道的通量能力适度增加，气孔关闭就可以加速 3 倍。GORK 通道的 K+ 敏感性是通道蛋白本身的特性，这应该有助于操纵 K+加速气孔关闭的外排能力。我的实验室发现了证据表明 GORK 门控的 K+ 依赖性与其簇中的组装有关。这些组件需要 GORK 所谓的“电压传感器域”(VSD) 相互交互。众所周知，VSD 的运动会将电压耦合到通道选通，因此 VSD 之间的相互作用很可能提供了一种协作自我调节的机制。我现在建议完成 GORK VSD 相互作用及其对通道控制和气孔运动的影响的分析。无论机制如何，很明显，这些发现提供了探索植物中此类 K+ 通道的独特且基本特性并操纵通道活动的方法，从而有可能增强植物气孔关闭和水分利用的动力学。

项目成果

Plant Physiology Launches Associate Features Editors.

植物生理学推出副专题编辑。

• DOI: http://dx.10.1104/pp.18.00113
• 发表时间: 2018
• 期刊: Plant physiology
• 影响因子: 7.4
• 作者: Blatt MR

Molecular Evolution of Grass Stomata.

草气孔的分子进化。

• DOI: 10.1016/j.tplants.2016.09.005
• 发表时间: 2017-02-01
• 期刊: Trends in plant science
• 影响因子: 20.5
• 作者: Zhonghua Chen;Guang Chen;F. Dai;Yizhou Wang;A. Hills;Y. Ruan;Guo;P. Franks;E. Nevo
• 通讯作者: E. Nevo

Liposome-based measurement of light-driven chloride transport kinetics of halorhodopsin.

基于脂质体的光驱动氯化物转运动力学的盐视紫红质测量。

• DOI: http://dx.10.1016/j.bbamem.2021.183637
• 发表时间: 2021
• 期刊: Biochimica et biophysica acta. Biomembranes
• 作者: Feroz H

New Faces behind the Scenes.

幕后新面孔。

• DOI: http://dx.10.1104/pp.18.00140
• 发表时间: 2018
• 期刊: Plant physiology
• 影响因子: 7.4
• 作者: Blatt MR

Evolutionary Conservation of ABA Signaling for Stomatal Closure

气孔关闭 ABA 信号的进化保守

• DOI: http://dx.10.1104/pp.16.01848
• 发表时间: 2017
• 期刊: Plant Physiology
• 影响因子: 7.4
• 作者: Cai S