CRC/TRR 175/1: The Green Hub. Central Coordinator of Acclimation in Plants

Plants constantly adjust (acclimate) to environmental changes, involving signalling and multiple genetic and metabolic changes. The chloroplast has emerged as a hub of acclimation, serving as both sensor and target of acclimation. The TRR175 brings together scientists from Munich, Kaiserslautern, Berlin/Golm and now Bielefeld, with outstanding expertise in the genetics, molecular biology, biochemistry and systems biology in the model species Arabidopsis, tobacco, Chlamydomonas, Camelina and now Chlorella. While in the first funding period, TRR175 focused on acclimation to cold, heat and high light, in the second funding period fluctuating light, drought and prolonged cold periods have been added. TRR175 has also targeted the role of the nucleocytosolic compartment in acclimation signalling. In addition, results from cyanobacterial adaptive laboratory evolution (ALE) experiments were successfully tested in plants. Quantitative experimentation pervaded the entire research network, providing a high level of synergy between physiological, biochemical and systems biology approaches. In the third funding period, we will also address acclimation in natural environments where multiple factors are changing. In Area A (Genetic Modulators), we will build on our finding that translation is critical for acclimation, particularly to cold, and investigate the role of phase separation, the spatial organisation of acclimation responses, and, in two new projects, acclimation to multiple environmental changes. In Area B (Metabolic Modulators), we will continue to identify modulators involved in redox regulation, transport processes and primary metabolism. In a new project, we will study the interaction between photoreceptors and acclimation and analyse structure-function relationships. In Area C (Signalling), we have found that biogenic and operational chloroplast signalling is strongly intertwined with acclimation pathways. A strong focus will be on nuclear transcription factors (TFs) as targets of chloroplast signalling, and on the interplay between the chloroplast unfolded membrane protein response and retrograde signalling. In Area D (Data Mining and Modelling), we will continue to model and reconstruct acclimation processes, integrate quantitative data to predict acclimation modulators, and extend this to TF networks in a new project. Our central scientific project Z1 will continue to bundle quantitative biology approaches and to pursue innovative projects. These include a new forward genetics tool (pamiR approach), a novel approach to improve photosynthetic acclimation (F2P2) and the extension of our ALE approach to green algae. For Camelina, we will generate several additional transgenic lines with improved carbohydrate and carotenoid metabolism. The expected results will help to unravel the complexity of acclimation and to address the challenge of effectively identifying genetic factors with high potential to ultimately improve acclimation in crops.