Abstracts (first author)
Comparative genomics of insect endosymbionts extracted from single hosts
Insect endosymbionts represent the paradigm of bacterial adaptation to a host-dependent life and their study contributes to our understanding on microbial ecology and genome evolution. Their informative nature is nonetheless counterpoised to their inaccessibility. Here we demonstrate that single-host endosymbiotic communities can be studied from next-generation sequencing data after purification and whole-genome amplification of endosymbionts. We focus on the comparative genomic study of two samples belonging to pure Hamiltonella defensa sequences extracted from two individual aphids from the tribe Macrosiphini. The assembly of their genomes show that they are 1.8 and 2.0 Mb-long, respectively, and their gene content is shown to be similar to that of other H. defensa genomes. We used this new data to fully resolve the phylogenetic relationships between the known H. defensa and related enterobacteria, and to reconstruct the history of gene gains and losses in their evolutionary lineage. Finally, we performed an in-depth analysis of the genome content and evolution of the APSE bacteriophage, inserted in the H. defensa genomes, which has a remarkable ecological importance in protecting the aphid host against parasitoid wasp infections.