Designing payload and spaceflight operations for plants from extreme terrestrial environments

Abstract

Terrestrial plants from the very limits of life are likely to harbor genes that confer an advantage in human space exploration. These plants are seemingly capable of performing mission critical functions in spaceflight and on extraterrestrial farms while informing directed gene manipulation in target plant species. However, their adaptations to physiologically extreme habitats may hinder the efficacy of routine laboratory techniques for model plants. We here present the development of Antarctic moss Ceratodon purpureus payload and flight operations for the ANT1 Radiation Tolerance Experiment with Moss in Orbit on the Space Station (ARTEMOSS) experiment to the International Space Station (ISS) given limited physical space and crew time. We demonstrate that the hydrophobic surface of Antarctic moss impedes chemical tissue fixation and precludes the use of RNAlater coupled with payload hardware deployed in standard plant spaceflight experiments. We show that deep-freezing the moss tissue on Petri plates provides adequate tissue fixation and allows the extraction of high-quality RNA suitable for gene expression profiling. We replaced hardware with stacks of Petri plates housing Antarctic moss and chemical fixation with deep-freezing in a cryogenic GLACIER freezer. Our design can be translated to other plant species to expand current experimentation techniques with plants from extreme terrestrial environments in order to advance human space exploration.