Perchlorate-tolerant bacterial strains isolated from the Mars-analog Qaidam Basin soils exposed to Earth's near space.

Earth's lower near space of 20-40 km above sea level with polyextreme conditions serves as a unique Mars analog for astrobiological research to investigate the limits of life on Earth and planetary protection considerations for Mars exploration. In this study, we exposed Mars-like desert regolith to near space at a float altitude of ~35 km and isolated four bacterial strains after exposure. In addition to stress tolerance to extreme environmental stressors, these strains represent a remarkable tolerance to perchlorate that is widespread in present-day Martian soils. These extremophilic bacterial strains screened through near-space exposure could serve as promising candidates for future astrobiological research in space stations or in laboratory-based planetary simulation environments.