The pathogenic bacterium Xylella fastidiosa threatens European agricultural and natural flora through the loss of economically, environmentally and culturally important host plants such as grape, olive and oak. This bacterium was first detected in Italy in 2013 and then in Corsica,France. Although X. fastidiosa is a generalist pathogen, infecting over 300 plant species, only a few plant species develop disease symptoms, and these infections always depend on a specific pathogen genotype. Although X. fastidiosa has been studied for over 80 years in the U.S.A., the determinants of X. fastidiosa host specificity remain unknown. In other words, it is not know why genotypes cause disease in one plant species but not another. Understanding what constrains X. fastidiosa host specificity is of paramount importance because it is currently not possible to predict what plant species are susceptible in Europe; this represents a major knowledge gap and limiting an adequate analysis of the risks posed by X. fastidiosa. This project aims to answer this important question by studying populations of the bacterium that are already host specific as well as one epidemic population exploiting a novel plant species in the EU. This will be done through collaboration between U.C. Berkeley -a leading expert on this pathogen- and BGPI, a French institute with excellent expertise in population genomics and interdisciplinary research. Besides reinforcing the link between the U.S.A. and European research on a subject of major importance, this project will result in the training of a European expert on this emerging pathogen. It will also broaden the Experienced Researcher's knowledge in plant-pathogen interactions. Finally, this project intends to disseminate knowledge on X. fastidiosa to the European society through (i) a collaboration with the French non-academic institute ANSES, (ii) a website dedicated to this pathogen and (iii) a collaboration with European farmers and agronomical schools.

The overarching goal of MEAL fish is to further understand the role of chaperone-Mediated autophagy (CMA) and Endosomal microautophagy (eMI) in AquacuLture fish, and to determine their relative contribution to nutrient utilization and metabolism. Deciphering the role of CMA and eMI in the control of carbohydrate metabolism will contribute to shed light on diverse physiological processes that can ultimately affect fish production, including nutrition and growth. During this trainee-development focused project, the fellow, through his interactions with the supervisor and the partners (H. Wodrich, and A. Herpin, from the stellar French research institutions CNRS and INRAE, respectively), will acquire diverse state-of-the-art skills that significantly enhance his scientific and technical knowledge. The mentor (I. Seiliez, UMR1419 INRAE NuMeA) is an internationally recognized leader in autophagy, fish metabolism and genomics and provides an excellent training environment for the applicant, an experienced researcher (ER) and emerging young leader in fish biology research. It is noteworthy the novelty and originality of the project, which proposes to gain insights on the function of a recently discovered process in fish, CMA, together with the barely known eMI, and to study its applied scope in aquaculture for the promotion of the use of non-fishmeal nutrients in aquafeeds. The project focuses on an important commercial species of the European aquaculture, the rainbow trout (O. mykiss). The European research competitiveness will be continuously enhanced throughout the project by the superior training of the ER, the interaction between multidisciplinary researchers, and translating for commercial use of the derived new knowledge on the regulation of CMA and eMI and its contribution to fish production. This project will ultimately contribute to the EU food sustainability, economy, employment and maintenance of its status as a group of high-level-knowledge countries.

Bacteria are fascinating organism, relatively and yet not fully understood. Fundamental research on bacteria led across the years to major technological breakthroughs like the discovery of genetic editing with CRISPR-Cas9. Besides, resistance of bacteria to antibiotics is becoming a growing public health concern, raising the need for a better understanding of the molecular mechanisms involved. We propose here to further our understanding of the molecular biology of bacteria by studying the dynamic of lipids in bacterial (B. Subtilis) membranes. In eukaryotic cells, it was found that lipid dynamics can reveal the micro- and nanoscale organisation of the plasma membrane, revealing a dynamic interplay between membrane components such as lipids, membrane proteins, and the actin cytoskeleton. Bacterial membranes were thought until recently to be much simpler, but accumulating evidence over the last ten years suggested that they too were highly heterogeneous and dynamic. However, very few studies so far focused on the question of lipid dynamics, in part because of the experimental complexity of such measurements. To address this, we will transfer new technologies based on fluorescence correlation spectroscopy (FCS), that were developed mainly for eukaryotic research, to the field of microbiology. With this unique methodology, we will answer a series of fundamental open questions: how do bacterial membranes organise at the nanoscale? Do they exhibit transient lipid-mediated interactions (called lipid rafts) as is thought to be the case in eukaryotes? Does MreB, bacterial equivalent of actin, also compartmentalises lipid diffusion? Answering these questions will help us build a holistic picture of the mechanisms associated with essential bacterial processes such as biofilm formation or antibiotic resistance, which will have far-reaching implications in both biology and medicine.