Hypobaric Resilience of Matrix Polysaccharide Biosynthesis in Plants.

Space habitats and transit vehicle interiors are proposed to operate at less than one Earth atmosphere (hypobaria) to minimize engineering costs in space-based bioregenerative life support systems (BLSS). Understanding how plants are affected by lower-pressure spaceflight environments and associated stressors will be vital for their use in life support within BLSS habitats. Whereas much is known about plant physiology in hypobaria, including the differential expression of genes involved in cell wall metabolism, little is known about the effects of hypobaria on plant cell wall matrix polysaccharide composition. The current study characterized the cell wall polysaccharide compositions of two Arabidopsis ecotypes and two mutants (sweet11 and pdc1) affecting hypobaria-responsive genes. Seedlings were cultivated in four atmospheric pressure environments (33, 50, 75, and 98 kPa) for 3 days prior to cell wall profiling using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Cell wall matrix polysaccharides were not consistently altered in three independent experiments at the atmospheric pressures listed above. These results reveal the resilience of plant cell walls to hypobaric stress and provide encouraging results for plants within low-pressure space habitats.