Response of Methanogenic Archaea from Siberian Permafrost and Non-permafrost Environments to Simulated Mars-like Desiccation and the Presence of Perchlorate

Abstract

Numerous preflight investigations were necessary prior to the exposure experiment BIOMEX on the International Space Station to test the basic potential of selected microorganisms to resist or even to be active under Mars-like conditions. In this study, methanogenic archaea, which are anaerobic chemolithotrophic microorganisms whose lifestyle would allow metabolism under the conditions on early and recent Mars, were analyzed. Some strains from Siberian permafrost environments have shown a particular resistance. In this investigation, we analyzed the response of three permafrost strains (Methanosarcina soligelidi SMA-21, Candidatus Methanosarcina SMA-17, Candidatus Methanobacterium SMA-27) and two related strains from non-permafrost environments (Methanosarcina mazei, Methanosarcina barkeri) to desiccation conditions (-80°C for 315 days, martian regolith analog simulants S-MRS and P-MRS, a 128-day period of simulated Mars-like atmosphere). Exposure of the different methanogenic strains to increasing concentrations of magnesium perchlorate allowed for the study of their metabolic shutdown in a Mars-relevant perchlorate environment. Survival and metabolic recovery were analyzed by quantitative PCR, gas chromatography, and a new DNA-extraction method from viable cells embedded in S-MRS and P-MRS. All strains survived the two Mars-like desiccating scenarios and recovered to different extents. The permafrost strain SMA-27 showed an increased methanogenic activity by at least 10-fold after deep-freezing conditions. The methanogenic rates of all strains did not decrease significantly after 128 days S-MRS exposure, except for SMA-27, which decreased 10-fold. The activity of strains SMA-17 and SMA-27 decreased after 16 and 60 days P-MRS exposure. Non-permafrost strains showed constant survival and methane production when exposed to both desiccating scenarios. All strains showed unaltered methane production when exposed to the perchlorate concentration reported at the Phoenix landing site (2.4 mM) or even higher concentrations. We conclude that methanogens from (non-)permafrost environments are suitable candidates for potential life in the martian subsurface and therefore are worthy of study after space exposure experiments that approach Mars-like surface conditions.

Limits of Life and the Habitability of Mars: The ESA Space Experiment BIOMEX on the ISS

“…The results presented in this special collection are arranged to provide an overview of each step of the processes involved in the BIOMEX experiment, that is, from selecting samples for simulation experiments to the final exposure experiments in space. Results from pretests on the chosen methanogenic archaeon of the genus Methanosarcina at the preselection level are reported in Serrano et al (2019). This archaeon was chosen because of its relevance with regard to its potential for being metabolically active on Mars.…”

Survival and growth of soil microbial communities under influence of sodium perchlorates

“…A higher tolerance to perchlorate was detected for Archaea in comparison to Bacteria according to the FISH analysis results. Earlier, archaeal family Halobacteriaceae showed to have a resistance to high UV and γ radiation levels, the ability to persist for a long time within brine inclusions in salt crystals, as well as tolerance to perchlorates (at a concentration of 1.2%) which participate in anaerobic metabolism (Oren, 2014; Serrano et al ., 2019). The maximum NaClO 4 concentration suitable for the growth of Archaea is currently considered to be 9.8% (Heinz et al ., 2020).…”

Habitability of Mars: How Welcoming Are the Surface and Subsurface to Life on the Red Planet?

“…Methanogens are of great interest for studying the potential for survival on Mars due to their ability to use hydrogen and carbon dioxide as the only energy and carbon sources, respectively [104]. They are often present in high numbers in the most extreme of environments and have been shown to survive and grow under low temperatures, high salinity, and both acidic and alkaline environments [128]. Moreover, some of their representatives, such as Methanosarcina spp., can use various carbon compounds to produce methane, which may provide an explanation for the detection of methane on Mars.…”