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发挥着至关重要的作用，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，植物蒸腾作用除了其一般的生态重要性之外，也是陆地气候和碳循环的关键。当受到水分限制时，植物通过协调蒸腾作用与根部介导的水分吸收来保持水分状态，这会导致气体交换并改善叶子的生长。如何实现这一点似乎只是初步了解，植物对水限制的反应涉及根和芽之间的快速水力对话，其本身依赖于植物内的水通量。水通道蛋白通道的传导、水分利用效率以及植物的气体交换均受应激激素脱落酸（ABA）的控制，脱落酸是调节植物对干旱反应的关键因素。不同的ABA敏感性和细胞和细胞不同的ABA信号反应。植物器官对于协调水稳态是必需的。由于在定义分子机制和确定分子机制方面的实验困难，在这些原理之外理解植物的长距离协调水稳态一直是一个挑战。在 ABA 信号传导和植物水力学控制领域的最新进展的推动下，法德联合研究小组认为在解决这一谜题方面处于有利地位。拟议的 ABAqua 项目将使用这些技术。并产生对 ABA 信号通路和水通道蛋白调节的前沿了解，以阐明如何通过根和叶之间的通讯实现水分稳态。该项目的重点是回答 ABA 对根和保卫细胞水力学的不同激素敏感性和作用是如何实现的。并将针对水通道蛋白的原型 ABA 信号模块的详细分子分析与磷酸蛋白质组学和失调表达相结合。拟南芥中的信号成分。全植物水平的分析将包括嫁接实验以及 ABA 信号和水通道蛋白突变体的组织特异性互补。这些分析将揭示关键的水力调节机制及其对水分充足条件下植物气体交换的影响。植物水稳态的新原理影响气体交换和随之而来的水利用变化，将为改进水限制下碳循环和植物生产力的预测提供机械基础。