"Bacteria with Multiple-Chromosomes (BMC) are relatively frequent. This project was designed to understand the advantages of such a genomic organization. Based on observations from comparative genomics these could be: shorter generation time by providing additionalorigins of replication, a differential chromosome copy number regulation that changes relatives gene doses of the unlinked gene sets and physical separation of the “core genome” and the “flexible genome” genes. This project will focus principally on the two last hypothesesaddressing them experimentally using leading-edge techniques. Vibrio cholera will be used as model. Its genome consists of two circular chromosomes that vary in their origin of replication (oriCI and oriCII respectively). The project will study extensively rearranged V. cholera strains obtained through genomic engineering techniques. Monochromosomal under oriCI or oriCII derivatives will be employed. Strains where both chromosomes will be under oriCI or oriCII control will also be analyzed. All strains transcriptomes will be analyzed using Illumina RNA-seq. These studies will show to what extent variation in genome structure can affect the relative gene expression. The exploration of the relative accessibility of the two chromosomes to DNA integration will be probed. These experiments will contribute to understand differences in architecture plasticity, gene content and lack of genetic flux between both chromosomes.The proposed researcher profile matches to project needs. The host institution has all facilities needed. All former trainees of the proposed supervisor have progressed in their academic careers. Hence the project is feasible and has great chances to be completed successfully.EU excellence and competiveness in Science will benefit from training shuch an excellent applicant in the best scientific environment and will give the chance to generate a long-term collaboration with Argentina."