Proteomic and Metabolomic Characteristics of Extremophilic Fungi Under Simulated Mars Conditions.

Adriana Blachowicz,Tamas Torok,Markus Kalkum,Abby J Chiang,Andreas Elsaesser,Clay C C Wang,Kasthuri Venkateswaran,Jason E Stajich,Pascale Ehrenfreund

doi:10.3389/fmicb.2019.01013

Abstract

Filamentous fungi have been associated with extreme habitats, including nuclear power plant accident sites and the International Space Station (ISS). Due to their immense adaptation and phenotypic plasticity capacities, fungi may thrive in what seems like uninhabitable niches. This study is the first report of fungal survival after exposure of monolayers of conidia to simulated Mars conditions (SMC). Conidia of several Chernobyl nuclear accident-associated and ISS-isolated strains were tested for UV-C and SMC sensitivity, which resulted in strain-dependent survival. Strains surviving exposure to SMC for 30 min, ISSFT-021-30 and IMV 00236-30, were further characterized for proteomic, and metabolomic changes. Differential expression of proteins involved in ribosome biogenesis, translation, and carbohydrate metabolic processes was observed. No significant metabolome alterations were revealed. Lastly, ISSFT-021-30 conidia re-exposed to UV-C exhibited enhanced UV-C resistance when compared to the conidia of unexposed ISSFT-021.

Highlights

Extremophiles are of interest to the National Aeronautics and Space Administration (NASA) due to their potential to survive hostile and extraterrestrial conditions (Rummel et al, 2002)
Twelve fungal strains isolated from Chernobyl nuclear accident sites, belonging to nine genera, and one International Space Station (ISS)-isolated strain were included in this study
It has been well documented that bacteria are associated with the spacecraft environment (La Duc et al, 2003, 2004; Newcombe et al, 2005), few studies address the persistence of fungi in this environment (La Duc et al, 2012; Weinmaier et al, 2015)

Summary

Introduction

Extremophiles are of interest to the National Aeronautics and Space Administration (NASA) due to their potential to survive hostile and extraterrestrial conditions (Rummel et al, 2002). Spacecraft-associated bacteria were more resistant than Bacillus subtillis 168, used as a dosimetric control (Newcombe et al, 2005). Exposure of B. subtilis 168 spores to dark space conditions (no UV) outside the International Space Station (ISS) and SMC for 559 days induced the expression of genes involved in DNA and protein damage responses, and oxidative and envelope stress (Nicholson et al, 2012). The first-generation of spores of another bacterium, Bacillus pumillus SAFR-032, isolated from the Jet Propulsion Laboratory (JPL) spacecraft assembly facility (SAF) was more UV-C resistant than the ground control counterparts following exposure to space UV conditions for 18 months. Extensive studies into the whole genome of SAFR032 revealed the presence of several DNA repair-associated genes that may have facilitated its survival and adaptation to harsh environmental conditions. Proteome analysis showed that stress response proteins, like superoxide dismutase, were increased in abundance when compared to the control (Vaishampayan et al, 2012)

Methods

Results

Conclusion