Plant pathogens devastate crops resulting in yield losses and increasing the use of often unsustainable pesticides. Understanding the basic mechanisms of the plant immune system will increase our ability to successfully combat plant diseases, satisfying the growing needs for sustainable food production, a future challenge for European agriculture.Cell death has a central role in innate immune responses in both animals and plants. The hypersensitive response (HR) is a plant-specific form of programmed cell death (PCD) occurring at the site of attempted pathogen invasion. A tight regulation of HR is essential in order to avoid unnecessary tissue damage beyond the infection site. However, the signaling pathways leading to HR still remain ill-defined. We have recently shown that Arabidopsis metacaspases, distant homologs of animal caspases, antagonistically control pathogen-triggered HR. However, their precise mode of action, regulation and substrates remain largely unknown. With this project we will use a combination of proteomic, genetic, cell biology and biochemical approaches to dissect the mechanisms underlying PCD control by this family of proteins. Defining the first plant deathosome will be a major breakthrough in plant sciences, moving forward with knowledge that can be directly translated into agronomically relevant species.We will use a multidisciplinary approach, benefitting from transnational collaborations already established by the candidate with research groups located in Europe and the USA. A Marie Curie International Incoming Fellowship will ensure the continuity of the candidate’s high-impact research at the host institution, an emerging reference center for plant sciences in Spain. Reintegration of the candidate will complement and synergize with the expertise of the host, directly contributing to European excellence.