Pivotal to the essential plant process of photosynthesis, which determines crop productivity, are iron-sulfur (Fe-S) cofactors. My outgoing phase host, Dr. Pilon at Colorado State University (USA), played a major role in defining the core components of the chloroplast Fe-S cluster assembly machinery essential for photosynthesis. Using an integrated biochemical-physiological-genetic approach in the model plant Arabidopsis thaliana I aim to investigate how the machinery components interact to produce Fe-S clusters, and how assembly is regulated. Specifically, I will study protein-protein interactions that mediate Fe-S assembly and use inducible RNA interference to create conditional loss-of-function mutants for individual components. This will also train me in methods developed in Dr. Pilon’s group: affinity purification, protein-protein interaction, in vitro reconstitution and RNAi. I will use these tools and skills in the return phase in the group of Dr. Gaymard in Montpellier (France) where I will establish a model for regulation of Fe-S assembly. Using the state of the art high-throughput “Phenopsis” platform I will study Fe-S assembly in the various mutant plant lines and investigate its response to changing environmental conditions, and stresses that limit agricultural productivity. This innovative project will provide basic knowledge and have additional impact for the breeding of more productive, nutritious plants. The importance of iron for food production and quality, key areas in the EU, cannot be overstated. This fellowship will contribute to European excellence and mobility via training, knowledge transfer and implementation of integrated methods. The project provides mentoring and management training; further complementary skills training is ensured by the highly interactive environments of both host labs at premier research institutes. The proposed project will provide excellent professional preparation for a group leader in the post-genomic era.