Nearly all aphids of economic importance belong to the Aphididae family, all species of which live symbiotically with an intracellular bacterium of the genus Buchnera (Enterobacteriaceae, close to Escherichia coli). This bacterium is currently used as the model for the endosymbiotic bacteria, about which we have the most molecular information. Its genome (640 kb) is extremely small compared to the genomes of other nonsymbiotic Enterobacteriaceae. One of the functional characteristics of this genome is that most of the biosynthesis pathways of the aphid’s essential amino acids have been conserved. The genome of the aphid (525 Mbp, 4 chromosomes) is currently undergoing assembly and annotation. A high degree of genetic complementarity at the metabolic level has been found between the two associated organisms (biosynthesis of nucleotides, amino acids, vitamins…).
We hope to improve our skills base in integrative biology by continuing to perform experiments ranging from the molecular mechanism to physiology (transcriptomics, analytical biochemistry, histology, and functional biology). One of our objectives is to root our research in some more specific questions with potential applications in terms of aphid control. At the same time, we are also continuing to invest in the modeling of systematic biology (analysis of genetic and metabolic networks).
The scientific project of our topic can be divided into 5 closely interconnected avenues of research: (1) Modeling symbiotic networks, (2) systematic characterization of trophic interactions, (3) functional characterization of trophic interactions, (4) functional characterization of the transportation system between the symbiotic partners, and (5) metabolomics of trophic interactions. These 5 avenues of research all focus on the analysis of the entire symbiotic system (bacteria and insects), and attempting to find a potential application in agronomics (looking for targets to control aphids by destabilizing the symbiotic system).