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PhD Opportunities in Geddes Lab

Plant with Root Microbiome
Photo Credit:
Dr. Barney Geddes
Illustration of Plant with Root Microbiome

2022 PhD Openings

We seek to fill two three-year funded PhD level graduate student positions under the supervision of Dr. Barney Geddes in the Department of Microbiological Sciences at North Dakota State University. Positions will begin spring, summer or fall 2022. The ideal applicants will have significant experience in molecular biology and microbial genetics.


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 MedicagoProceedings of the National Academy of Sciences118(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 microbiology5(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 communications10(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 microbiology82(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 biotechnology32, pp.216-222.