Yeasts in the Era of Astrobiological Research

Leo, Patrick; Onofri, Silvano

doi:10.1007/s41745-023-00378-5

Cited by 3 publications

(3 citation statements)

References 82 publications

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“…Fungi are found in low abundance in SAFs, seemingly insignificant (Moissl et al, 2007;Plemenitaš et al, 2014;Venkateswaran et al, 2014;Checinska et al, 2015;Weinmaier et al, 2015;Hendrickson et al, 2017). However, their resiliency suggests that fungi remain a particular concern in regard to forward planetary protection (Leo and Onofri, 2023). The diversity of the fungal assemblage in SAFs appears to be very much lower than that of the bacterial assemblage.…”

Section: Discussionmentioning

confidence: 99%

“…Fungi currently hold the record for growth at the lowest a w (Pitt and Christian, 1968;Williams and Hallsworth, 2009). Therefore, discussions of planetary protection need to include salinotolerant fungi (Leo and Onofri, 2023). Finding fungi capable of long-term survival and proliferation in concentrated MgSO 4 and NaClO 3 brines, demonstrates that fungi may be carried by spacecraft and further have the potential to influence life detection missions or native microbial communities.…”

Section: Discussionmentioning

confidence: 99%

“…Broad tolerance to salinity, without halophilicity, with slower growth at high salinities, supports the suggestion that fungal communities in hypersaline environments are not highly specialized. Fungi use mechanisms similar to those of bacteria to survive in brines, including tight membranes, ion efflux pumps and the accumulation of compatible solutes to balance internal osmotic potential with that of the medium (Plemenitaš et al, 2014;Leo and Onofri 2023;Suryanarayanan and Ravishankar, 2023). In addition, fungi reinforce their cell wall to withstand increased turgor pressure and resist salt uptake (Gunde-Cimerman and Zalar, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Succession of the fungal community of a spacecraft assembly clean room when enriched in brines relevant to Mars

Carte,

Chen,

Clark

et al. 2024

International Journal of Astrobiology

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Spacecraft can carry microbial contaminants from spacecraft assembly facilities (SAFs) to the cold arid surface of Mars that may confound life detection missions or disrupt native ecosystems. Dry hygroscopic sulphate and (per)chlorate salts on Mars may absorb atmospheric humidity and deliquesce at certain times to produce dense brines, potential sources of liquid water. Microbial growth is generally prohibited under the non-permissive condition of extremely low water activity in the frigid potential brines on Mars. Here we challenged the microbial community from samples of the Jet Propulsion Laboratory SAF with the extreme chemical conditions of brines relevant to Mars. Enrichment cultures in SP medium supplemented with 50% MgSO4 or 20% NaClO3 were inoculated from washes of SAF floor wipes. Samples were taken for each of the first four weeks and then at six months after inoculation to follow changes in the SAF microbial community under high salinity for long periods. Metagenomic DNA extracts of community samples were examined by Illumina sequencing of 18S rRNA gene sequences using fungal primers. The fungal assemblage during the first month of enrichment was predominantly common Ascomycetes, primarily Saccharomyete yeasts. Basidiomycetes were detected, mainly in the Microbotryomycetes and Tremellomycetes. Fungi were much less abundant in enrichment cultures at 50% MgSO4 than at 20% NaClO3. After 6 months of enrichment, few fungi remained. Microbes persisting from the JPL SAF microbial community in aged cultures enriched at extreme salinities might be the most capable of subsequently surviving and proliferating at the near surface of Mars. The SAF fungal assemblage did not survive and proliferate as well as the SAF bacterial community.

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