Iron acquisiton is essential for pathogenic Bacteria. In host, iron is not free : he’s bound to proteins like transferrin or ferritin used for storage and homeostasis, or included inside hemoproteins. In order to remove this iron, Bacteria developped several systems including secreted molecules (siderophore) with high affinity for iron, or surface proteins. In Bacillus cereus (opportunistic pathogen for insect and human), we have demonstarted that both surface protein IlsA and siderophore bacillibactin are involved in iron acquisiton of exogenous Mammalian ferritin, and are important for infection (Segond et al, 2014, Plos Pathogen). In this project, we aim i) to assess the importance of ferritin sources in iron acquisition efficiency. We will focus on insect ferritin, in order to test the hypothesis that IlsA is better adapted to an invertebrate ferritin (mostly extracellular) rather than vertebrate ferritin. In an other part, we’ll investigate ii) the importance of siderophore binding protein FeuA in virulence of Bacillus cereus during host infection. To better understanding we’ll use Galleria mellonella as insect model. Finally, iii) in vivo trials will be run to determine a time-related and/or tissue specific expression of bacillibactin and IlsA in the insect, by using reporter genes and microscopic observations. This project will provide molecular and mechanistic insights during host infection, and new fallouts about bioavailability of ferritin iron contained in insect floors for industrial applications.