Adaptive strategies and energetic profiles of bacteria in permafrost and temperate environments: a comparative study

Abstract

Exploring microbial life in extreme conditions has not only challenged our definition of habitability but is expanding our understanding of where extraterrestrial life may occur. Permafrost, which covers approximately 27% of Earth’s surface, offers a unique window into microbial resilience in an extreme sub-zero environment, which is considered analogous to environments found on icy planets like Mars. Despite such harsh conditions, permafrost sustains diverse and active microbial communities. However, the energy dynamics and genomic adaptations that enable their survival remain largely unexplored. Here, we compare the maintenance energy requirements and genomic traits of permafrost-derived bacteria with bacteria from temperate environments to gain a better understanding of how these microbes survive in permafrost. We find that permafrost bacteria maintain stable maintenance energy levels as temperatures decrease, suggesting the presence of energy-use efficiency adaptations. Further genomic analysis of permafrost bacteria identified distinct gene adaptations related to stress response and resource acquisition, highlighting increased gene copies in pathways such as transporters and folding proteins. These results not only challenge previous assumptions about microbial energy dynamics but also provide insights into the complex mechanisms enabling microbial life to thrive under some of the most extreme conditions on Earth.