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

Cytoplasmic incompatibility (CI) is an intriguing, widespread, symbiont-induced reproductive failure that decreases offspring production of arthropods through crossing incompatibility of infected males with uninfected females or with females infected with a distinct symbiont genotype. For years, the molecular mechanism of CI remained unknown. Recent genomic, proteomic, biochemical, and cell biological studies have contributed to understanding of CI in the alphaproteobacterium Wolbachia and implicate genes associated with the WO prophage. Besides a recently discovered additional lineage of alphaproteobacterial symbionts only moderately related to Wolbachia, Cardinium (Bacteroidetes) is the only other symbiont known to cause CI, and genomic evidence suggests that it has very little homology with Wolbachia and evolved this phenotype independently. Here, we present the first transcriptomic study of the CI Cardinium strain cEper1, in its natural host, Encarsia suzannae, to detect important CI candidates and genes involved in the insect-Cardinium symbiosis. Highly expressed transcripts included genes involved in manipulating ubiquitination, apoptosis, and host DNA. Female-biased genes encoding ribosomal proteins suggest an increase in general translational activity of Cardinium in female wasps. The results confirm previous genomic analyses that indicated that Wolbachia and Cardinium utilize different genes to induce CI, and transcriptome patterns further highlight expression of some common pathways that these bacteria use to interact with the host and potentially cause this enigmatic and fundamental manipulation of host reproduction

The terminal oxidases of Paracoccus denitrificans

Summary Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding subunit i of the aaa-type cytochrome c oxidase have been isolated before, namely ctaDi and ctaDil. Each of these genes can be expressed separately to complement a double mutant (ActaDi, ActaDIl), indicating that they are isoforms of subunit i of the aas-type oxidase. The genomic locus of a quinol oxidase has been isoiated: cyoABC. This protohaem-containing oxidase, called cytochrome bb^, is the oniy quinoi oxidase expressed under the conditions used, in a tripie oxidase mutant (sctaDI, ActaDII, cyoS::Km") an aiternative cytochrome c oxidase has t>een characterized; this ebbstype oxidase has been partiaiiy purified. Both cytochrome ass and cytochrome b/>3 are redox-driven proton pumps. The proton-pumping capacity of cytochrome cbb^ has been analysed; arguments for and against the active transport of protons by this novel oxidase compiex are discussed

Data from: The effect of Wolbachia on the lifetime reproductive success of its insect host in the field

Wolbachia is a widespread endosymbiont that induces dramatic manipulations of its host's reproduction. Although there has been substantial progress in the developing theory for Wolbachia–host interactions and in measuring the effects of Wolbachia on host fitness in the laboratory, there is a widely recognized need to quantify the effects of Wolbachia on the host fitness in the field. The wasp Anagrus sophiae, an egg parasitoid of planthoppers, carries a Wolbachia strain that induces parthenogenesis, but its effects on the fitness of its Anagrus host are unknown. We developed a method to estimate the realized lifetime reproductive success of female wasps by collecting them soon after they die naturally in the field, counting the number of eggs remaining in their ovaries and quantifying Wolbachia density in their body. We sampled from a highly infected A. sophiae population and found no evidence for Wolbachia virulence and possible evidence for positive effects of Wolbachia on realized reproductive success

Segoli & Rosenheim 2013

Data for egg loads of newly emerged females collected as pupae from the field (potential fitness), estimated number of eggs laid by females collected dead from the field (realized fitness), hind tibia length, and relative Wolbachia density in the body individual females (estimated as -ddCt)

Development of a multi-locus sequence typing system helps reveal the evolution of Cardinium hertigii, a reproductive manipulator symbiont of insects

Background Cardinium is an intracellular bacterial symbiont in the phylum Bacteroidetes that is found in many different species of arthropods and some nematodes. This symbiont is known to be able to induce three reproductive manipulation phenotypes, including cytoplasmic incompatibility. Placing individual strains of Cardinium within a larger evolutionary context has been challenging because only two, relatively slowly evolving genes, 16S rRNA gene and Gyrase B, have been used to generate phylogenetic trees, and consequently, the relationship of different strains has been elucidated in only its roughest form. Results We developed a Multi Locus Sequence Typing (MLST) system that provides researchers with three new genes in addition to Gyrase B for inferring phylogenies and delineating Cardinium strains. From our Cardinium phylogeny, we confirmed the presence of a new group D, a Cardinium clade that resides in the arachnid order harvestmen (Opiliones). Many Cardinium clades appear to display a high degree of host affinity, while some show evidence of host shifts to phylogenetically distant hosts, likely associated with ecological opportunity. Like the unrelated reproductive manipulator Wolbachia, the Cardinium phylogeny also shows no clear phylogenetic signal associated with particular reproductive manipulations. Conclusions The Cardinium phylogeny shows evidence of diversification within particular host lineages, and also of host shifts among trophic levels within parasitoid-host communities. Like Wolbachia, the relatedness of Cardinium strains does not necessarily predict their reproductive phenotypes. Lastly, the genetic tools proposed in this study may help future authors to characterize new strains and add to our understanding of Cardinium evolution.NSFNational Science Foundation (NSF) [IOS-1256905]; center for Insect Science at the University of ArizonaOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]