Transcriptomic profiling of haloarchaeal denitrification through RNA-Seq analysis

Denitrification, a crucial biochemical pathway prevalent among haloarchaea in hypersaline ecosystems, has garnered considerable attention in recent years due to its ecological implications. Nevertheless, the underlying molecular mechanisms and genetic regulation governing this respiration/detoxification process in haloarchaea remain largely unexplored. In this study, RNA-sequencing was used to compare the transcriptomes of the haloarchaeon Haloferax mediterranei under oxic and denitrifying conditions, shedding light on the intricate metabolic alterations occurring within the cell such as the accurate control of the metal homeostasis. Furthermore, the investigation identifies several genes encoding transcriptional regulators and potential accessory proteins with putative roles in denitrification. Among these are bacterioopsin transcriptional activators, proteins harbouring a domain of unknown function (DUF2249), and a cyanoglobin. Additionally, the study delves into the genetic regulation of denitrification, finding a regulatory motif within promoter regions that activates numerous denitrification-related genes. This research serves as a starting point for future molecular biology studies in haloarchaea, offering a promising avenue to unravel the intricate mechanisms governing haloarchaeal denitrification, a pathway of paramount ecological importance. Haloferax mediterranei R4 ATCC33500 cells were grown under oxic and denitrifying conditions in media supplemented with nitrate. The aim of this research was to perform comparative transcriptomics (RNA-Seq) to analyse the gene expression changes under denitrifying conditions and identify the metabolic changes of these cells , as well as genes encoding proteins with a potential role in the denitrification pathway .