Genomes of Rickettsia species

Abstract

Rickettsia species are strictly intracellular Gram-negative bacteria that infect a variety of mammalian hosts, including humans. Many Rickettsia species are associated to arthropod vectors. Their adaptation to life within eukaryotic cells resulted in a progressive genomic degradation via pseudogenization of genes involved in various metabolisms. Paradoxically, some species exhibit conjugative plasmids and gene duplications. As the genomes from most species have been sequenced, we review here the main characteristics of rickettsial genomes.