Endosymbiosis is an important evolutionary process which has led to the formation of organelles such as mitochondria and plastids. A process where two unrelated cellular lineages, in specific circumstances, can become one. These cellular compartments have changed how complex cells function and how the eukaryotic form diversified, and represent a critical acquisition that underpinned the evolution of multicellular organisms like plants and animals. However, we still do not know how unrelated cells can form stable interactions that lead to obligate endosymbiotic associations. For example, we do not understand the cell biology that underpins such associations or how cellular interactions can lead to stable ecological interactions.
The Richards’ lab has recently been awarded an ERC consolidator grant to develop new approaches to dissect how cells of different species can interact to form ‘stable’ endosymbiotic interactions. This project uses a range of methods including cell biological experiments, high-throughput gene knock-down approaches and phylogenomic analyses to understand the evolutionary, ecological and cellular basis of endosymbiotic interactions. Within this project, we are developing a systems biology approach to study how the ciliate protist Paramecium bursaria interacts with its green algal endosymbionts. We have evidence that this is a multi-player association and that bacterial endosymbionts are also involved in the interaction, potentially functioning as mediators, commensals or pathogens. The aim of this D. Phil. project is therefore to investigate the diversity and role of the bacterial endosymbionts in this multi-player endosymbiotic interaction.
There is scope within this project to focus on genome evolution or, alternatively, a more experimental laboratory-based project, or a combination of both. Previous work within the lab has produced a large range of data on the Paramecium bursaria system. As such the D. Phil. candidate will be given the intellectual space and support to develop their own ideas within this general subject. Furthermore, the team includes a range of senior staff working on bioinformatic and cellular biological approaches, providing a highly supportive environment for the proposed D. Phil. project. This is a new branch of research from the Richards’ lab, see the following references [1-6] for related themes. For recent work from our lab with overlapping interest please see [7-9].
If interested please contact Professor Thomas Richards ([email protected]
) in the first instance. Application procedure details at: https://www.ox.ac.uk/admissions/graduate/courses/dphil-zoology?wssl=1
. The application deadline is 24th January 2020.
1. Lowe, C D., Minter, E J., Cameron, D D., and Brockhurst, M A. (2016). Shining a light on exploitative host control in a photosynthetic endosymbiosis. Curr Biol 26, 207-211.
2. Husnik, F., Nikoh, N., Koga, R., Ross, L., Duncan, R.P., Fujie, M., Tanaka, M., Satoh, N., Bachtrog, D., Wilson, Alex C.C., et al. (2013). Horizontal gene transfer from diverse bacteria to an insect genome enables a tripartite nested mealybug symbiosis. Cell 153, 1567-1578.
3. Keeling, P.J., and McCutcheon, J.P. (2017). Endosymbiosis: the feeling is not mutual. Journal of Theoretical Biology 434, 75-79.
4. Spribille, T., Tuovinen, V., Resl, P., Vanderpool, D., Wolinski, H., Aime, M.C., Schneider, K., Stabentheiner, E., Toome-Heller, M., Thor, G., et al. (2016). Basidiomycete yeasts in the cortex of ascomycete macrolichens. Science.
5. Gong, J., Qing, Y., Guo, X., and Warren, A. (2014). “Candidatus Sonnebornia yantaiensis”, a member of candidate division OD1, as intracellular bacteria of the ciliated protist Paramecium bursaria (Ciliophora, Oligohymenophorea). Systematic and Applied Microbiology 37, 35-41.
6. Kwong, W.K., del Campo, J., Mathur, V., Vermeij, M.J.A., and Keeling, P.J. (2019). A widespread coral-infecting apicomplexan with chlorophyll biosynthesis genes. Nature 568, 103-107.
7. Milner, D.S., Attah, V., Cook, E., Maguire, F., Savory, F.R., Morrison, M., Müller, C.A., Foster, P.G., Talbot, N.J., Leonard, G., et al. (2019). Environment-dependent fitness gains can be driven by horizontal gene transfer of transporter-encoding genes. Proceedings of the National Academy of Sciences 116, 5613.
8. Savory, F.R., Milner, D.S., Miles, D.C., and Richards, T.A. (2018). Ancestral function and diversification of a horizontally acquired oomycete carboxylic acid transporter. Molecular Biology and Evolution, msy082.
9. Monier, A., Chambouvet, A., Milner, D.S., Attah, V., Terrado, R., Lovejoy, C., Moreau, H., Santoro, A.E., Derelle, É., and Richards, T.A. (2017). Host-derived viral transporter protein for nitrogen uptake in infected marine phytoplankton. Proc Natl Acad Sci USA 114, E7489-E7498.