Transcriptome Sequencing Reveals Novel Candidate Genes forCardinium 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.

A Tangled Web: Origins of Reproductive Parasitism

“…Conversely, we did not find evidence for CI-like TA modules in the genome of the CI-inducing Cardinium strain cEper1, an endoparasite of Encarsia wasps ( Penz et al. 2012 ), although a recent report illuminated unrelated candidate CI-inducing proteins in this species ( Mann et al. 2017 ).…”

Comparative Genomics of Wolbachia–Cardinium Dual Endosymbiosis in a Plant-Parasitic Nematode

“…In theory, obligate mutualism could lead to 100% prevalence, but this is not known in Cardinium . Instead, high prevalence may be a sign of strong reproductive parasitism: CI and high Cardinium prevalence have been observed in spider mites ( Gotoh et al, 2007 ; Kopecky et al, 2013 ; Zhao et al, 2013 ; Zhang et al, 2016a ; Zhu et al, 2018 ) and Encarsia wasps ( Hunter et al, 2003 ; Zchori-Fein et al, 2004 ; Zchori-Fein and Perlman, 2004 ; Perlman et al, 2008 ; White et al, 2011 ; Gebiola et al, 2017 ; Mann et al, 2017 ).…”

“…Because both Cardinium and Wolbachia are thought to manipulate host cellular processes including reproduction using a set of eukaryote-derived protein domains, such as the ubiquitination-modulating proteins ( Schmitz-Esser et al, 2010 ; Beckmann et al, 2017 ; Mann et al, 2017 ; White et al, 2017 ), we examined these in detail and found moderate abundance of these in cPpe, particularly FBOX domain genes expanded and unique USP homologous in cPpe, cBtQ1, and cEper1, with blast similarity to nematodes and algae. These domains are thought to modify ubiquitination, marking proteins for degradation or changing their interactions with other proteins.…”

The draft genome of a new Verminephrobacter eiseniae strain: a nephridial symbiont of earthworms

“…The P-loop containing nucleoside triphosphate hydrolase superfamily proteins play a crucial role in determining the host specificity of the endophyte Streptomyces scabrisporus NF3 during symbiosis (Ceapă et al 2018). Besides, the transcriptome analysis of the Cardinium strain cEper1, in its host parasitic wasps, Encarsia suzannae demonstrated the upregulation of the P-loop NTPase domain-containing gene CAHE_0544 upregulated within the male insects (Mann et al 2017). The V. eiseniae msu protein dataset associated with P-loop containing nucleoside triphosphate hydrolase family denoted the presence of AAA family ATPase, ABC transporters, ATP-binding cassette domain-containing proteins, and DEAD/DEAH box helicase.…”