Perchlorate affects the expression of genes involved in ETC, oxidative phosphorylation, and removal of oxidative species. Gene names of DEGs belonging to those processes are shown. Expression changes of DEGs are indicated with red (upregulated) or blue (downregulated) triangles next to gene names. NDH: NAD(P)H dehydrogenase; Sdh: succinate dehydrogenase; Q: quinone; bc1: cytochrome bc1 complex; Hcy: halocyanine; Cox: cytochrome c oxidase; Cba: ba3 cytochrome c oxidase; ROS: reactive oxidative species; Sod: superoxide dismutase; Prx: peroxiredoxin; Trx: thioredoxin. — Genetics and Molecular Biology via PubMed
Perchlorate is a strong chaotropic agent that causes macromolecule denaturation, DNA damage, and oxidative stress.
However, perchlorate deliquescence is thought to promote the formation of liquid salt brines, even at hyper-arid and cold environments, such as the Martian regolith. For that reason, the detection of high levels of perchlorate at different locations on the Martian surface led to hypotheses about the existence of Martian microenvironments compatible with life, especially with those organisms tolerant to hyper-salinity and perchlorate.
Extreme halophilic archaea have been proposed as the best candidates to inhabit those environments not only due to their high tolerance to salinity and perchlorate, but also because of their resistance to a wide variety of stress conditions.
Since specific perchlorate responses remain largely unknown, in this work, we have analyzed the molecular mechanisms of perchlorate tolerance exhibited by the model extreme halophilic archaeon Haloferax volcanii using a transcriptomic approach.
We report that perchlorate produced transcriptional effects opposite to those of salinity, and we propose that the “salt-in” strategy could promote high perchlorate tolerance in extreme halophilic archaea due to the intracellular accumulation of KCl, which may shield the chaotropic activity of perchlorate.
This natural adaptation would be enhanced by changes in other stress responses like DNA repair, refolding and turnover of damaged proteins, removal of oxidative species, and tRNA modifications, among others. These results may help to understand how life could survive on Mars, now or in the past, and highlight the importance of extreme halophiles in the development of in situ resource utilization systems.
Molecular adaptations specific to extreme halophilic archaea could promote high perchlorate tolerance, Genetics and Molecular Biology via PubMed
Molecular adaptations specific to extreme halophilic archaea could promote high perchlorate tolerance, Genetics and Molecular Biology (open access)
Astrobiology, genomics,