Cardinium symbiosis as a potential confounder of mtDNA based phylogeographic inference in Culicoides imicola (Diptera: Ceratopogonidae), a vector of veterinary viruses

Parasites & Vectors

Claire Garros¹  Gert Venter²  Stefanos Siozios³  Jack Pilgrim³  Gregory D. D. Hurst³  Matthew Baylis⁴ 

[1] ASTRE, University of Montpellier, Cirad, INRA, Montpellier, France;Cirad, UMR ASTRE, 34398, Montpellier, France;Agricultural Research Council- Onderstepoort Veterinary Research, Pretoria, South Africa;Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa;Faculty of Health and Life Sciences, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK;Faculty of Health and Life Sciences, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK;Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, UK;

关键词: Cardinium;    Endosymbiont;    Symbiosis;    COI;    Culicoides;   

DOI  :  10.1186/s13071-020-04568-3

来源: Springer

【 摘 要 】

BackgroundCulicoides imicola (Diptera: Ceratopogonidae) is an important Afrotropical and Palearctic vector of disease, transmitting viruses of animal health and economic significance including African horse sickness and bluetongue viruses. Maternally inherited symbiotic bacteria (endosymbionts) of arthropods can alter the frequency of COI (cytochrome c oxidase subunit I) mitochondrial haplotypes (mitotypes) in a population, masking the true patterns of host movement and gene flow. Thus, this study aimed to assess the mtDNA structure of C. imicola in relation to infection with Candidatus Cardinum hertigii (Bacteroides), a common endosymbiont of Culicoides spp.MethodsUsing haplotype network analysis, COI Sanger sequences from Cardinium-infected and -uninfected C. imicola individuals were first compared in a population from South Africa. The network was then extended to include mitotypes from a geographic range where Cardinium infection has previously been investigated.ResultsThe mitotype network of the South African population demonstrated the presence of two broad mitotype groups. All Cardinium-infected specimens fell into one group (Fisher’s exact test, P = 0.00071) demonstrating a linkage disequilibrium between endosymbiont and mitochondria. Furthermore, by extending this haplotype network to include other C. imicola populations from the Mediterranean basin, we revealed mitotype variation between the Eastern and Western Mediterranean basins (EMB and WMB) mirrored Cardinium-infection heterogeneity.ConclusionsThese observations suggest that the linkage disequilibrium of Cardinium and mitochondria reflects endosymbiont gene flow within the Mediterranean basin but may not assist in elucidating host gene flow. Subsequently, we urge caution on the single usage of the COI marker to determine population structure and movement in C. imicola and instead suggest the complementary utilisation of additional molecular markers.

【 授权许可】

CC BY