Transcriptome Sequencing Reveals Novel Candidate Genes for Cardinium hertigii -Caused Cytoplasmic Incompatibility and Host-Cell Interaction

Abstract

The majority of insects carry maternally inherited intracellular bacteria that are important in their hosts’ biology, ecology, and evolution. Some of these bacterial symbionts cause a reproductive failure known as cytoplasmic incompatibility (CI). In CI, the mating of symbiont-infected males and uninfected females produces few or no daughters. The CI symbiont then spreads and can have a significant impact on the insect host population. Cardinium , a bacterial endosymbiont of the parasitoid wasp Encarsia in the Bacteroidetes , is the only bacterial lineage known to cause CI outside the Alphaproteobacteria , where Wolbachia and another recently discovered CI symbiont reside. Here, we sought insight into the gene expression of a CI-inducing Cardinium strain in its natural host, Encarsia suzannae . Our study provides the first insights into the Cardinium transcriptome and provides support for the hypothesis that Wolbachia and Cardinium target similar host pathways with distinct and largely unrelated sets of genes.