Flux4LIVES_Thylakoid ion flux-Linking photosynthetic efficiency with osmotic stress response

未来几十年，全球对粮食和燃料的需求急剧增加，需要迅速发展具有更高光合作用效率和对环境挑战的稳健性或耐受性的作物。最近的工作表明，光合作用光保护机制的激活和失活的动力学(或速度)对于避免光损伤和提高光合作用的光捕获效率至关重要。有趣的是，对类囊体离子转运蛋白缺陷突变体的初步表征揭示了类囊体离子通量在调节这些动态反应中的关键作用。此外，类囊体离子载体作用于钙信号，钙信号是渗透胁迫反应的中心媒介。综上所述，这些发现强烈表明，类囊体离子通量是植物改良的一个有前途的、或许是关键的目标，但我们对关键成分的了解还远远不完整。我们的初步结果表明，更多的、以前未确定的蛋白质参与了微调类囊体膜离子稳态机制的网络，并且多个离子通量系统协同发挥其生理功能。我们联盟的一个关键目标是开发一个数学模型，将对类囊体离子通量的修改与光合作用效率和高渗透胁迫反应联系起来。该模型将允许测试在各种环境下提高植物产量的新策略。我们将使用两个数据集来验证和训练我们的模型：(A)来自拟南芥和番茄突变体的实验数据，这些突变体在类囊体膜离子转运蛋白中的功能丧失和获得；以及(B)来自西班牙商业种植的番茄的数据。该项目汇集了一个在叶绿体生物学、类囊体离子通量、生物能量学、光谱学、表型、模型、离子和生物化学方面具有互补专业知识的国际小组。我们建议进行以下工作包(WP)：(I)完成类囊体膜离子转运蛋白质清单；(Ii)确定类囊体膜离子通量相互作用在光合作用和高渗透胁迫抗性中的作用；(Iii)确定类囊体膜离子通量影响高渗透胁迫响应的过程；(Iv)分析类囊体膜离子通量对番茄主要农艺性状的影响；以及(V)建立模拟光合作用效率和抗盐性随类囊体离子通量增加而增加的模型。

The global need for dramatic increases in food and fuel over the next decades requires the rapid development of crops with enhanced photosynthetic efficiency and robustness or tolerance to environmental challenges. Recent work suggests that the dynamics (or speed) of activation and deactivation of photoprotective mechanisms of photosynthesis are critical for avoidance of photodamage and for improving the efficiency of light capture of photosynthesis. Intriguingly, the initial characterization of mutants defective in thylakoid ion transport proteins uncovered a key role for thylakoid ion flux in regulating these dynamic responses. Moreover, thylakoid ion carriers act on Ca2+ signalling, a central mediator in the osmotic stress response. Taken together, these findings strongly suggest thylakoid ion flux as a promising, perhaps pivotal, target for plant improvement, yet our knowledge of key components is far from complete. Our preliminary results suggest that additional, previously uncharacterized, proteins are involved in fine-tuning the thylakoid network of ion homeostatic mechanisms and that multiple ion flux systems cooperate towards their physiological functions. A key goal of our consortium is to develop a mathematical model which will link modifications to thylakoid ion flux with photosynthetic efficiency and hyperosmotic stress response. The model will allow for testing new strategies to improve plant yield in various environments. We will use two data sets to verify and train our model: (a) experimental data derived from Arabidopsis and tomato mutants with loss- and gain of function in thylakoid ion transport proteins and (b) data derived from tomatoes grown commercially in Spain. The project brings together an international group with complementary expertise in chloroplast biology, thylakoid ion flux, bioenergetics, spectroscopy, phenotyping, modelling, ionomics, and biochemistry. We propose to pursue the following work packages (WP): (i) complete the thylakoid ion transport protein inventory; (ii) Determine the role of thylakoid ion flux interactions in photosynthesis and hyperosmotic stress resistance; (iii) Identify the process by which thylakoid ion flux impacts the hyperosmotic stress response; (iv) Analyse thylakoid ion flux impacts on key agronomical traits in tomato; and (v) Generate a model for simulating increases to photosynthetic efficiency and salt stress resistance as a function of thylakoid ion flux.