Transcriptional Regulation of Bacterial Nitrous Oxide Emissions

Leigh, Tomas (2024) Transcriptional Regulation of Bacterial Nitrous Oxide Emissions. Doctoral thesis, University of East Anglia.

Preview

PDF Download (2MB) | Preview

Abstract

Nitrous oxide (N2O) is a potent greenhouse gas and a major threat to the ozone layer. It is primarily produced during the final stage of microbial denitrification through the enzymatic reduction of nitric oxide (NO). This process mainly happens in terrestrial environments, with agricultural soils being dominant N2O emitters due to the large quantities of nitrogen added as fertilisers. These fertilisers, containing ammonium and nitrate, provide soil microorganisms with sufficient nitrogen species to denitrify at an elevated rate. Each stage of denitrification requires unique enzymes that have been well-characterised, however, much less research has been done on the regulation of gene expression for each process. Further investigating transcriptional regulation could help unearth why incomplete denitrification occurs.

Small RNAs (sRNAs) are small, non-coding RNA molecules which posttranscriptionally regulate gene expression, yet their role in regulating the denitrification pathway is not well understood. Recent studies have identified sRNAs and their chaperones as potentially crucial to the pathway’s regulation. In this study, we used the model soil denitrifier Paracoccus denitrificans to characterise the role of two sRNAs and the RNA chaperone Hfq on N2O emissions when overexpressed under denitrifying conditions. The overexpression of these regulators caused varying impacts on N2O production and consumption. Overexpression of P. denitrificans’ sRNA11 resulted in an 80% reduction in N2O emissions and a significantly impaired cell growth rate. Hfq overexpression also substantially reduced N2O emissions, showing a potential overarching role of Hfq in sRNA denitrification regulation. sRNA Pda200 overexpression also decreased N2O emissions, experimentally confirming hypotheses from previous studies.

These findings show that the sRNAs and chaperone examined here are relevant to the denitrification pathway in P. denitrificans. Therefore, sRNAs and their chaperones should be further considered in environmental bacteria when developing strategies to reduce N2O emissions.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Jennifer Whitaker
Date Deposited:	04 Apr 2025 12:00
Last Modified:	04 Apr 2025 12:00
URI:	https://ueaeprints.uea.ac.uk/id/eprint/98937
DOI:

Downloads

Actions (login required)

View Item