ABA-dependent control of plant hydraulics in acclimation to water deficit

植物水力学在适应水分亏缺时依赖于 ABA 的控制

• 批准号: 406910788
• 负责人: Professor Dr. Erwin Grill
• 金额: --
• 依托单位: Lehrstuhl für Botanik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/406910788?language=en
• 关键词: ABA; dependent; control; plant; hydraulics

Water plays a crucial role in terrestrial ecosystems with plants acting as a major factor in water cycling. By dominating the water flux from the soil to atmosphere, plant transpiration is key for terrestrial climate and carbon cycling. Besides its general ecological importance, water availability is the major constraint for higher plant productivity in the field. When subjected to water limitation, plants homeostase their water status by coordinating transpiration with root-mediated water uptake. This leads to altered gas exchange and can result in improved leaf water use efficiency. How this is achieved is only rudimentarily understood. It appears that the plant response to water limitation involves a rapid hydraulic dialog between roots and shoots which itself relies on fundamental plant physiological mechanisms. Water flux within the plant is facilitated by water-conducting aquaporin channels and water use efficiency as well as plant’s gas exchange are governed by the stress hormone abscisic acid (ABA) which is the key factor in adjusting plant responses to drought. Different ABA sensitivities and distinct ABA signalling responses of cells and plant organs are required for coordinated water homeostasis.Understanding the long distance-coordinated water homeostasis of plants beyond these principles has been a challenge. Progress in this field has been very slow over the last decade because of the experimental difficulties in defining molecular mechanisms and to test them in plants. Initiated by recent advances in the field of ABA signaling and the control of plant hydraulics, the joint French-German research team feels to be in an excellent position to achieve a breakthrough on this enigma. The proposed ABAqua project will use and generate frontline understanding of ABA signalling pathways and aquaporin regulation to elucidate how water homeostasis is achieved through communication between roots and leaves. An emphasis of the project is to answer how the different hormone sensitivities and actions of ABA on root and guard cell hydraulics are realized and relayed to water-conducting aquaporins. Detailed molecular analysis of prototypic ABA signaling modules targeting aquaporins will be employed in combination with phosphoproteomics and expression of deregulated signaling components in Arabidopsis. Analyses at the whole-plant level will include grafting experiments and tissue-specific complementation of ABA signaling and aquaporin mutants. These analyses will reveal the key hydraulic regulatory mechanisms and their impact on gas exchange in plants under well-watered condition and drought. The emerging principles of plant’s water homeostasis, affecting gas exchange and concomitant changes in water use, will provide a mechanistic basis for improved prediction of carbon cycling and plant productivity under water limitation.

水在陆地生态系统中起着至关重要的作用，植物是水循环的主要因素。通过控制从土壤到大气的水通量，植物蒸腾作用是陆地气候和碳循环的关键。除了具有一般的生态重要性外，水分有效性是田间植物生产力提高的主要制约因素。当受到水分限制时，植物通过协调蒸腾和根介导的水分吸收来平衡水分状态。这导致了气体交换的改变，可以导致叶片水分利用效率的提高。这是如何实现的，人们只是初步了解。植物对水分限制的响应涉及根和芽之间的快速水力对话，这本身依赖于植物的基本生理机制。水分在植物体内的流动主要通过水孔蛋白通道进行，水分利用效率和植物的气体交换受胁迫激素ABA的调控，ABA是调节植物对干旱反应的关键因子。不同的ABA敏感性和不同的ABA信号反应需要细胞和植物器官的协调水稳态。在这些原理之外理解植物长距离协调的水分平衡一直是一个挑战。在过去的十年中，由于在定义分子机制和在植物中进行测试方面的实验困难，这一领域的进展非常缓慢。受ABA信号和植物水力控制领域最新进展的启发，法德联合研究小组认为，在这个谜上取得突破是非常有利的。拟议的ABAqua项目将利用ABA信号通路和水通道蛋白调控的前沿知识来阐明如何通过根和叶之间的交流实现水稳态。该项目的重点是回答ABA对根和保护细胞水力学的不同激素敏感性和作用是如何实现的，并将其传递给导水的水通道蛋白。针对水通道蛋白的原型ABA信号模块的详细分子分析将结合磷酸化蛋白质组学和拟南芥中失调信号成分的表达。整个植株水平的分析将包括嫁接实验和ABA信号和水通道蛋白突变体的组织特异性互补。这些分析将揭示水分充足和干旱条件下植物的关键水力调节机制及其对气体交换的影响。植物水分平衡的新原理，影响气体交换和伴随的水分利用变化，将为改进水分限制下的碳循环和植物生产力预测提供机制基础。