Transcriptional and environmental control of bacterial nitrous oxide emissions

(ROWLEY_UBIO19ARIES)

Transcriptional and environmental control of bacterial nitrous oxide emissions

(ROWLEY_UBIO19ARIES)

Project Description

Supervisors

Dr Gary Rowley (UEA Biological Sciences)

Dr Jon Todd (UEA)

Prof Elizabeth Baggs (University of Edinburgh)

Background

Nitrous oxide (N2O) is a potent greenhouse gas. Although atmospheric N2O levels are lower than that of CO2, it has a 300-fold greater global warming potential, and represents around 10% of total global greenhouse gas emissions. Denitrifying bacteria play key roles in the synthesis and consumption of N2O. In oxygen (O2)-limited environments, these bacteria can use nitrate (eg from fertiliser) to respire. Here, nitrate is converted via nitrite, nitric oxide and N2O to dinitrogen (N2), a process termed denitrification. The last step in denitrification is carried out by nitrous oxide reductase, NosZ. NosZ is the major enzyme on the planet responsible for the destruction of N2O, without it atmospheric levels of N2O would be much greater. Given the importance of this enzyme, it is surprising that we do not understand the switches inside the bacteria that allow NosZ to be produced. The fact that so much N2O is produced from natural environments implies that NosZ in the microbial population is not always active.  An understanding of the switches that control NosZ is crucial if novel chemical or biological mitigation strategies are to be developed to drive bacterial communities to be net N2O consumers rather than producers.

The Project

Building from our recent publications  we are looking for a highly-motivated student who will determine:

  • the key environmental variables that regulate nosZ transcription in pure cultures of model soil and marine denitrifying bacteria.
  • the role of bacterial sRNA in responding to these variables and regulating N2O emissions.

Student Role

The student will be involved in all aspects of the project from experimental design and environmental sampling, to laboratory analyses and data management. The project will involve a period of time based in Edinburgh. The student will also be part of our outreach activities.

Training

To study this exciting project we will employ a multi-disciplinary approach incorporating microbial culture and genetics, RNA-seq, and microbial ecology.  Training will be provided in these areas, but the student must have a BSc with modules covering at least one of them. Presentation of results at international conferences will be an important aspect of the training provided.

References

  • Gaimster, H., Chalklen, L., Alston, M., Munnoch, J. T., Richardson, D. J., Gates, A. J., and Rowley, G. (2016) Genome-Wide Discovery of Putative sRNAs in Paracoccus denitrificans Expressed under Nitrous Oxide Emitting Conditions. Front Microbiol 7, 1806
  • Sullivan, M. J., Gates, A. J., Appia-Ayme, C., Rowley, G., and Richardson, D. J. (2013) Copper control of bacterial nitrous oxide emission and its impact on vitamin B12-dependent metabolism. Proc Natl Acad Sci U S A 110, 19926-19931
  • Hartop, K. R., Sullivan, M. J., Giannopoulos, G., Gates, A. J., Bond, P. L., Yuan, Z., Clarke, T. A., Rowley, G., and Richardson, D. J. (2017) The metabolic impact of extracellular nitrite on aerobic metabolism of Paracoccus denitrificans. Water Res 113, 207-214
  • Gaimster, H., Alston, M., Richardson, D. J., Gates, A. J., and Rowley, G. (2018) Transcriptional and environmental control of bacterial denitrification and N2O emissions. FEMS Microbiol Lett 365
  • Leff, J. W., Bardgett, R. D., Wilkinson, A., Jackson, B. G., Pritchard, W. J., De Long, J. R., Oakley, S., Mason, K. E., Ostle, N. J., Johnson, D., Baggs, E. M., and Fierer, N. (2018) Predicting the structure of soil communities from plant community taxonomy, phylogeny, and traits. The ISME Journal 12, 1794-1805

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