PhD Opportunities in Geddes Lab
A Microbial Symbiont for N2-Fixing Cereals
The PhD projects build on previous research developing fundamental understandings and systems to support a “holy grail” of synthetic biology - engineering nitrogen fixing cereals. While advances have been made towards developing cereal root nodule organs, to fully realize the dream of N2-fixing cereals we must uncover foundational knowledge that guides the development of a compatible rhizobium symbiont that will “boot-up” in a cereal root nodule and efficiently deliver nitrogen to the host. Using synthetic biology, microbial genomics and large-scale genome-manipulation the Ph.D. students will work on complementary projects to develop this knowledge. These projects will involve 1) Deciphering the minimal genetic programming required for rhizobia to perform as optimal symbionts for their legume partners 2) Experimental engineering of new-to-nature symbioses between rhizobia and non-host legumes as a model system to uncover and overcome the challenges associated with achieving root nodule invasion and nitrogen-fixation in future root-nodule forming cereals.
How to Apply
We value diversity as a source of strength, creativity and innovation, and believe we will grow and learn better together with a diverse team. Interested candidates should contact Dr. Barney Geddes with a letter of motivation and CV. Formal applications will be submitted through the NDSU Graduate School. Review of applications will begin immediately and continue until positions are filled.
Relevant Publications
Geddes, B.A., Kearsley, J.V., Huang, J., Zamani, M., Muhammed, Z., Sather, L., Panchal, A.K. and Finan, T.M., 2021. Minimal gene set from Sinorhizobium(Ensifer) meliloti pSymA required for efficient symbiosis with Medicago. Proceedings of the National Academy of Sciences, 118(2), p.e2018015118.
Ryu, M.H., Zhang, J., Toth, T., Khokhani, D., Geddes, B.A., Mus, F., Garcia-Costas, A., Peters, J.W., Poole, P.S., Ané, J.M. and Voigt, C.A., 2020. Control of nitrogen fixation in bacteria that associate with cereals. Nature microbiology, 5(2), pp.314-330.
Geddes, B.A., Paramasivan, P., Joffrin, A., Thompson, A.L., Christensen, K., Jorrin, B., Brett, P., Conway, S.J., Oldroyd, G.E. and Poole, P.S., 2019. Engineering transkingdom signalling in plants to control gene expression in rhizosphere bacteria. Nature communications, 10(1), pp.1-11.
Mus, F., Crook, M.B., Garcia, K., Costas, A.G., Geddes, B.A., Kouri, E.D., Paramasivan, P., Ryu, M.H., Oldroyd, G.E., Poole, P.S. Udvardi, M.K., Voigt, C. W., Ané J-M., and Peters, J. W. 2016. Symbiotic nitrogen fixation and the challenges to its extension to nonlegumes. Applied and environmental microbiology, 82(13), pp.3698-3710.
Geddes, B.A., Ryu, M.H., Mus, F., Costas, A.G., Peters, J.W., Voigt, C.A. and Poole, P., 2015. Use of plant colonizing bacteria as chassis for transfer of N2-fixation to cereals. Current opinion in biotechnology, 32, pp.216-222.
