One of the major challenges for plant productivity is balancing survival under stress conditions with the investment of resources into growth and reproduction. The role of plant mitochondria and chloroplasts has been recognised as pivotal not only in growth permissive conditions, but also under a variety of stresses, ranging from water to pathogen attack. Furthermore, the energy organelles are considered to be more than just targets of stress-induced damage, but are thought to be part of the first signalling steps that launch an efficient stress response. Plant mitochondria and chloroplasts are able to signal their functional status to the nucleus, a process termed retrograde signalling. These retrograde signals alter nuclear gene expression of organellar proteins and importantly, also of many other proteins functioning in hormone metabolism and transport. Together these signalling events can enhance plant survival. However, the nature of the signals and how they are transmitted is only beginning to be understood. Recently several breakthroughs were made by the identification of transcription factors that can activate or repress transcriptional responses to mitochondrial or chloroplast dysfunction. In the present project, I will focus on identifying additional components that lead to activation of mitochondrial retrograde signalling in plants.