Environmental Microbiology (2017) 19, 4238-4255
Jack Pilgrim, Mats Ander, Claire Garros, Matthew Baylis, Gregory D.D. Hurst and Stefanos Siozios (2017)
Torix group Rickettsia are widespread in Culicoides biting midges (Diptera: Ceratopogonidae), reach high frequency and carry unique genomic features
Environmental Microbiology 19 (10), 4238-4255
Abstract: There is increasing interest in the heritable bacteria of invertebrate vectors of disease as they present novel targets for control initiatives. Previous studies on biting midges (Culicoides spp.), known to transmit several RNA viruses of veterinary importance, have revealed infections with the endosymbiotic bacteria, Wolbachia and Cardinium. However, rickettsial symbionts in these vectors are underexplored. Here, we present the genome of a previously uncharacterized Rickettsia endosymbiont from Culicoides newsteadi (RiCNE). This genome presents unique features potentially associated with host invasion and adaptation, including genes for the complete non-oxidative phase of the pentose phosphate pathway, and others predicted to mediate lipopolysaccharides and cell wall modification. Screening of 414 Culicoides individuals from 29 Palearctic or Afrotropical species revealed that Rickettsia represent a widespread but previously overlooked association, reaching high frequencies in midge populations and present in 38% of the species tested. Sequence typing clusters the Rickettsia within the Torix group of the genus, a group known to infect several aquatic and hematophagous taxa. FISH analysis indicated the presence of Rickettsia bacteria in ovary tissue, indicating their maternal inheritance. Given the importance of biting midges as vectors, a key area of future research is to establish the impact of this endosymbiont on vector competence.
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Database assignments for author(s): Matthew Baylis
Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Culicoides impunctatus | Sweden | |||
| Culicoides impunctatus | United Kingdom | |||
| Culicoides pulicaris | France | |||
| Culicoides pulicaris | Sweden | |||
| Culicoides pulicaris | United Kingdom | |||
| Culicoides newsteadi | France | |||
| Culicoides newsteadi | Sweden | |||
| Culicoides newsteadi | United Kingdom |
