Crop yield is strongly affected by abiotic stress such as heat and drought, both intensified by climate change. More stress-tolerant crops with a higher intrinsic yield are urgently needed to ensure food security to a growing population. The communication between nutrient assimilating and depositing organs is of uttermost importance for crop yield. Two key protein kinases that function in this communication are the growth-stimulating TOR kinase and its antagonistic SnRK1. Together with the sugar-sensing and SnRK1-inhibiting trehalose-6-P, they form the cornerstone of growth regulation in plants. We will exploit the signalling networks involving these kinases and T6P to generate high-order combinatorial mutants in Arabidopsis through CRISPR-Cas9 and Prime Editing. Adequate screening assays will be implemented to search for high-yield and stress-resilience. The potential of plant cell suspension cultures to enhance this labour-intensive screening will be evaluated. Detailed functional analysis of plants with beneficial phenotypes will be conducted providing molecular insight in the underlying genetic interactions altering plant growth. In parallel, a dynamic in vivo kinase reporter system will be developed to monitor TOR/SnRK1 activity during plant development. These reporters will allow us to assess the influence of the mutations on kinase activity. In the long term, we aim to transfer the obtained knowledge to higher-yielding, more stress-resilient cereal crop varieties.