Prion domains in Plant Environmental Response

植物通过调整自身的发育来适应环境，以响应包括光和温度在内的线索。这使它们能够预测压力，通过生长和发育的变化做出反应，并在不同的环境条件下优化它们的生存和繁殖成功率。随着气候变化，成功适应的过程对许多物种来说是一个挑战。由于气候变化，植物物候已经发生了变化，但其潜在机制尚不清楚。该联盟最近发现控制生长、发育和应激反应的关键转录调控因子含有朊病毒样结构域（PrDs）。prd赋予了响应环境信号进行相变（液-液相分离，LLPS）的能力，使这些蛋白质能够作为发育开关。该项目重点研究含有转录因子过多3 (PLT3)，热休克因子1a （HSFA1a）和植物色素相互作用因子4,5和7（“pif”）的PrD。这些转录因子在植物发育和胁迫反应中起主要调控作用，均具有prd。我们已经证明它们在体外和/或体内经历了LLPS。利用体外、结构、建模和体内的综合方法，我们将确定对LLPS重要的变量，检查不同氨基酸序列在相分离中的作用，并设计具有改变LLPS的突变体。通过迭代体外表征，包括小角度x射线和中子散射（SAXS/SANS）研究，荧光显微镜和使用过程粒度模拟和原子模型的理论建模，我们的目标蛋白的LLPS规则将被确定。这些体外和模拟结果将与模式植物拟南芥的瞬时表达系统和稳定转化系的体内研究相关。荧光标记的靶蛋白和突变体的体内成像、ChIP-seq研究和转录组分析将使我们能够直接将植物的生物反应与我们蛋白质的LLPS特性联系起来。正在研究的系统将允许在细胞和生物体水平上直接探测LLPS的影响。了解PrDs如何根据物理化学环境控制蛋白质活性，将使我们能够直接调节植物的生长和胁迫反应。这将代表着我们对植物如何适应环境的理解发生了重大变化。这个跨学科项目结合了法国和德国合作伙伴在结构生物学、生物物理建模、体外分子分析和植物研究方面的专业知识。

Plants adapt to the environment by adjusting their development in response to cues including light and temperature. This enables them to anticipate stresses, respond via changes in their growth and development and optimize their survival and reproductive success under varying environmental conditions. With climate change, the process of successful adaptation represents a challenge for many species. The phenology of plants has already altered due to climate change, but the underlying mechanisms of this are not well understood. The consortium has recently discovered that key transcriptional regulators controlling growth, development and stress response contain prion-like domains (PrDs). PrDs confer the ability to undergo phase-change (liquid-liquid phase separation, LLPS) in response to environmental signals, enabling these proteins to act as developmental switches. The project focuses on the PrD containing transcription factors PLETHORA 3 (PLT3), HEAT SHOCK FACTORA1a (HSFA1a) and the PHYTOCHOROME INTERACTING FACTORS 4,5 and 7 (“PIFs”). These transcription factors act as master regulators in plant development and stress response and all possess PrDs. We have demonstrated that they undergo LLPS in vitro and/or in vivo. Using an integrated in vitro, structural, modeling and in vivo approach, we will determine the variables that are important for LLPS, examine the role of different amino acid sequences in phase separation and design mutants with altered LLPS. Through iterative in vitro characterization including studies by small angle X-ray and neutron scattering (SAXS/SANS), fluorescence microscopy and theoretical modeling using course grained simulations and atomistic models, the rules governing LLPS of our target proteins will be determined. These in vitro and modeling results will be correlated with in vivo studies in transient expression systems and stably transformed lines in the model plant, Arabidopsis thaliana. In vivo imaging of fluorescently labelled target proteins and mutants, ChIP-seq studies and transcriptome analysis will allow us to directly relate plant biological response to the LLPS properties of our proteins. The system under study will allow the direct probing of the effects of LLPS at the cellular and organism level. Understanding how PrDs control protein activity in response to the physicochemical environment will enable us to directly tune growth and stress responses in plants. This will represent a step-change in our understanding of how plants adapt to their environment. This interdisciplinary project combines expertise from French and German partners in structural biology, biophysical modeling, in vitro molecular assays, and in planta studies.