Multifactorial stress combination as a driving force in the decline of uni- and multicellular organisms

Abstract

This doctoral thesis investigates how plants respond to multifactorial environmental stress conditions (MFSC) caused by climate change, focusing on both the crop Solanum lycopersicum (tomato) and the alga Chlamydomonas reinhardtii. Physiological, transcriptomic, metabolomic, and proteomic analyses revealed that stress complexity leads to declining photosynthetic performance, increased oxidative damage, and metabolic reprogramming in tomato. Jasmonic acid was shown to be crucial for mitigating oxidative stress. In C. reinhardtii, MFSC impaired growth and chlorophyll content, with the ROS-deficient mutant rbo1 showing reduced extracellular H₂O₂ and increased cell aggregation. Transcriptomic profiling identified conserved stress-responsive genes across species, suggesting a shared molecular signature. Proteomic and metabolomic data indicated adaptations prioritizing redox balance and osmoprotection. Overall, this work highlights conserved stress response pathways in unicellular and multicellular systems, offering targets for enhancing crop resilience.