Investigating the evolutionary dynamics and genetic mechanisms of Wolbachia-host interactions

Wolbachia are bacteria that are widespread endosymbionts found in more than half of all arthropod species, like all endosymbionts they potentially affect many aspects of their host biology. In particular, many Wolbachia ensure their own transmission to the next generation by selfishly manipulating the reproduction of their host as Wolbachia are primarily transmitted from the host mother to her offspring. This research investigates both short and long-term interactions between hosts and Wolbachia. Specifically, it aims to understand how Wolbachia manipulate host reproduction and how hosts co-evolve to resist these manipulations. The results will be of broad significance to both basic and applied questions in biology. First, given their abundance and effects on their arthropod hosts, endosymbionts including Wolbachia likely contribute to species diversification and broader patterns of biodiversity. The findings will help understand how endosymbionts contribute to the evolutionary and ecological processes that generate and maintain biodiversity. Second, Wolbachia are currently used for biocontrol of insect vectors that transmit human pathogens as well as of agricultural pests that cause harm to plants. The evolutionary dynamics that occur in natural host-endosymbiont interactions likely also occur in engineered biocontrol systems. The findings of this study will inform the potential consequences of wide-scale release of Wolbachia-infected insects, including both how the host evolves to modulate Wolbachia’s effects, as well as how Wolbachia co-evolves to result in strain replacements. Critical to completing the scientific aims is training the next generation of the STEM workforce. This research will provide mentored research opportunities for trainees of all levels, who will receive hands-on training in scientific research methods and communication. This project specifically investigates the genetic interactions and co-evolutionary dynamics between two sister Drosophila fly species and two Wolbachia strains. In the wild, D. recens is infected with two closely related strains of Wolbachia, both of which cause moderate cytoplasmic incompatibility, or the death of offspring of uninfected females and infected males, in this host. When transferred to the host D. subquinaria, one of these Wolbachia strains causes strong cytoplasmic incompatibility, while the other causes strong male killing, where the sons of infected females die. This project will result in key insights into i) the mechanisms by which endosymbionts cause reproductive manipulations, ii) the mechanisms by which hosts counteract these reproductive manipulations, and iii) the dynamics of how endosymbionts invade and spread through host populations. To complete the aims, the research will integrate field assays, molecular genetics, genetic mapping, population genetics, and laboratory assays. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2548547 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Kelly Dyer | Institution: University of Georgia Research Foundation Inc, ATHENS, GA | Award Amount: $1,229,568 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2548547 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2548547.html