Integrating population genetic structure, microbiome, and pathogens presence data in Dermacentor variabilis

Paula Lado; Bo Luan; Michelle E J Allerdice; Christopher D Paddock; Sandor E Karpathy; Hans Klompen

doi:10.7717/peerj.9367

Integrating population genetic structure, microbiome, and pathogens presence data in Dermacentor variabilis

PeerJ. 2020 Jul 7:8:e9367. doi: 10.7717/peerj.9367. eCollection 2020.

Authors

Paula Lado¹, Bo Luan², Michelle E J Allerdice³, Christopher D Paddock³, Sandor E Karpathy³, Hans Klompen¹

Affiliations

¹ Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, United States of America.
² Statistics, The Ohio State University, Columbus, OH, United States of America.
³ Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America.

Abstract

Tick-borne diseases (TBDs) continue to emerge and re-emerge in several regions of the world, highlighting the need for novel and effective control strategies. The development of effective strategies requires a better understanding of TBDs ecology, and given the complexity of these systems, interdisciplinary approaches are required. In recent years, the microbiome of vectors has received much attention, mainly because associations between native microbes and pathogens may provide a new promising path towards the disruption of pathogen transmission. However, we still do not fully understand how host genetics and environmental factors interact to shape the microbiome of organisms, or how pathogenic microorganisms affect the microbiome and vice versa. The integration of different lines of evidence may be the key to improve our understanding of TBDs ecology. In that context, we generated microbiome and pathogen presence data for Dermacentor variabilis, and integrated those data sets with population genetic data, and metadata for the same individual tick specimens. Clustering and multivariate statistical methods were used to combine, analyze, and visualize data sets. Interpretation of the results is challenging, likely due to the low levels of genetic diversity and the high abundance of a few taxa in the microbiome. Francisella was dominant in almost all ticks, regardless of geography or sex. Nevertheless, our results showed that, overall, ticks from different geographic regions differ in their microbiome composition. Additionally, DNA of Rickettsia rhipicephali, R. montanensis, R. bellii, and Anaplasma spp., was detected in D. variabilis specimens. This is the first study that successfully generated microbiome, population genetics, and pathogen presence data from the same individual ticks, and that attempted to combine the different lines of evidence. The approaches and pre-processing steps used can be applied to a variety of taxa, and help better understand ecological processes in biological systems.

Keywords: Ecology; Microbiome; Ticks; Anaplasma; Core microbiome; Dermacentor variabilis; Integrative approach; Population genetics; Rickettsia; Tick-borne diseases.

Grants and funding

This work was supported by the Ohio State University: the Graduate School’s Alumni Grants for Graduate Research and Scholarship to Paula Lado. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.