Sensing of O 2 and nitrate by bacteria: alternative strategies for transcriptional regulation of nitrate respiration by O 2 and nitrate

• Published in: Environmental microbiology Vol. 23; no. 1; pp. 5 - 14
• Main Authors: Unden, Gottfried, Klein, Robin
• Format: Journal Article
• Language: English
• Published: England 01.01.2021
• Subjects: Anaerobiosis; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Gene Expression Regulation, Bacterial; Nitrates - metabolism; Oxygen - metabolism; Phosphoric Monoester Hydrolases - genetics; Phosphoric Monoester Hydrolases - metabolism; Phosphorylation; Phosphotransferases - genetics; Phosphotransferases - metabolism; Staphylococcus - genetics; Staphylococcus - metabolism
• ISSN: 1462-2912; 1462-2920
• DOI: 10.1111/1462-2920.15293

Many bacteria are able to use O 2 and nitrate as alternative electron acceptors for respiration. Strategies for regulation in response to O 2 and nitrate can vary considerably. In the paradigmatic system of E . coli (and γ‐proteobacteria), regulation by O 2 and nitrate is established by the O 2 ‐sensor FNR and the two‐component system NarX‐NarL (for nitrate regulation). Expression of narGHJI is regulated by the binding of FNR and NarL to the promoter. A similar strategy by individual regulation in response to O 2 and nitrate is verified in many genera by the use of various types of regulators. Otherwise, in the soil bacteria Bacillus subtilis (Firmicutes) and Streptomyces (Actinobacteria), nitrate respiration is subject to anaerobic induction, without direct nitrate induction. In contrast, the NreA‐NreB‐NreC two‐component system of Staphylococcus (Firmicutes) performs joint sensing of O 2 and nitrate by interacting O 2 and nitrate sensors. The O 2 ‐sensor NreB phosphorylates the response regulator NreC to activate narGHJI expression. NreC‐P transmits the signal for anaerobiosis to the promoter. The nitrate sensor NreA modulates NreB function by converting NreB in the absence of nitrate from the kinase to a phosphatase that dephosphorylates NreC‐P. Thus, widely different strategies for coordinating the response to O 2 and nitrate have evolved in bacteria.