Microsome-associated proteome modifications ofArabidopsisseedlings grown on board the International Space Station reveal the possible effect on plants of space stresses other than microgravity

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Growing plants in space for using them in bioregenerative life support systems during long-term human spaceflights needs improvement of our knowledge in how plants can adapt to space growth conditions. In a previous study performed on board the International Space Station (GENARA A experiment STS-132) we evaluate the global changes that microgravity can exert on the membrane proteome of Arabidopsis seedlings. Here we report additional data from this space experiment, taking advantage of the availability in the EMCS of a centrifuge to evaluate the effects of cues other than microgravity on the relative distribution of membrane proteins. Among the 1484 membrane proteins quantified, 227 proteins displayed no abundance differences between µ g and 1 g in space, while their abundances significantly differed between 1 g in space and 1 g on ground. A majority of these proteins (176) were over-represented in space samples and mainly belong to families corresponding to protein synthesis, degradation, transport, lipid metabolism, or ribosomal proteins. In the remaining set of 51 proteins that were under-represented in membranes, aquaporins and chloroplastic proteins are majority. These sets of proteins clearly appear as indicators of plant physiological processes affected in space by stressful factors others than microgravity.
The authors would like to thank the National Aeronautics and Space Administration (NASA) who successfully performed the spaceflight experiment; they also thank the astronauts for performing the required tasks on board the ISS. We acknowledge the Norwegian User Support and Operations Center team (NUSOC) for the ground and space preparation of the GENARA-A experiment and we thank the European Aeronautic Defense and Space Company (Astrium EADS) for the design and building of the hardware. We also thank the European Space Agency (ESA) and the Centre National d’Etudes Spatiales(CNES) for their scientific and financial support.