Prion domains in Plant Environmental Response

• Applicants: Professorin Dr. Yvonne Stahl; Professor Dr. Philip Anthony Wigge, Ph.D.
• Subject Area: Plant Cell and Developmental Biology ; Plant Biochemistry and Biophysics
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 490818643

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.

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partners: Dr. Alessandro Barducci; Dr. Luca Costa; Privatdozentin Dr. Chloe Zubieta