Beneficial microbes mitigate molecular stress responses and accelerate developmental pathways in host animals during spaceflight

As humans continue the manned exploration of space, it is critical to understand the impact of this harsh environment on the beneficial microbes that interact with their bodies. Here, we explore whether the onset of symbiotic associations between microbes and animals are impacted during spaceflight. We used the association between the bobtail squid Euprymna scolopes and its beneficial bacterium Vibrio fischeri as an animal model system to examine how spaceflight affects symbiotic interactions at the transcriptomic, metabolomic, and lipidomic levels over time. Our results suggest that in the spaceflight environment, symbiotic microbes can mitigate molecular stress responses of the host animal and accelerate normal developmental pathways, such as neurogenesis and tissue morphogenesis. Overall, this work provides evidence that beneficial microbes can effectively colonize nascent host epithelial tissues in microgravity and play a critical role in shaping the host tissue environment to promote stability of symbiosis during spaceflight.