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. Overall design: 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 .

反硝化作用是高盐生态环境中嗜盐古菌（haloarchaea）广泛存在的关键生化途径，近年来因其重要的生态学意义而受到广泛关注。然而，嗜盐古菌中调控该呼吸/解毒过程的潜在分子机制与遗传调控机制，迄今仍未得到充分解析。本研究采用RNA测序（RNA-sequencing）技术，对比了地中海嗜盐盒菌（Haloferax mediterranei）在有氧与反硝化条件下的转录组，揭示了细胞内发生的复杂代谢重塑，包括金属稳态的精准调控。此外，本研究还鉴定出多个编码转录调控因子及潜在辅助蛋白的基因，这些蛋白被推测在反硝化过程中发挥功能，其中包括细菌视蛋白转录激活因子、携带未知功能结构域（DUF2249）的蛋白，以及蓝球蛋白。同时，本研究深入探究了反硝化作用的遗传调控机制，在启动子区域中发现了可激活众多反硝化相关基因的调控基序。本研究为未来嗜盐古菌的分子生物学研究奠定了基础，为解析嗜盐古菌反硝化作用的复杂调控机制这一具有重要生态学意义的途径提供了极具前景的研究方向。整体实验设计：将地中海嗜盐盒菌（Haloferax mediterranei）R4 ATCC33500菌株置于添加硝酸盐的培养基中，分别在有氧与反硝化条件下进行培养。本研究旨在通过比较转录组学（RNA-Seq）分析，解析反硝化条件下的基因表达变化，明确该菌株的代谢重塑情况，并鉴定出在反硝化途径中潜在发挥功能的蛋白编码基因。