Oxygen Deficiency in Spaceflight & its Impact on Plants’ Adaptive Changes

The goal of this study was to investigate the effects of hypoxic conditions in spaceflight. The
distribution of genes involved with hypoxia in Arabidopsis thaliana and Brassica rapa were
analyzed with the results from past spaceflight experiments to evaluate genes for future studies.
Transcriptomes data of two different spaceflight studies of Arabidopsis thaliana from the NASA
GeneLab database, GLDS-7 and GLDS-17, were compared. DNA microarrays were utilized for
transcription profiling to conduct these studies. For GLDS-7, the response in spaceflight was
studied with approaches that collected gene expression data. Leaves, hypocotyls, and root tissues
were compared to the whole plant. For GLDS-17, seedlings and undifferentiated cultured cells
were placed in the Biological Research in Canisters (BRIC), specifically BRIC-16. The genes
related to hypoxia in Arabidopsis thaliana from these two studies were compared to genes in
Brassica rapa with the TOAST database to evaluate similarities.
When transcriptomes were analyzed for GLDS-7 and 17, genes that were considered significant
had p-values ≤ 0.05 and log fold change values ≤ -1 or ≥1. Sixteen genes fulfilled the criteria.
The genes related to hypoxia were alcohol dehydrogenase, elongation factor, ethylene-responsive
factor, GUS, heat-shock proteins, NAP, RAP2.12, and RD20. The genes most impacted by
spaceflight were heat-shock proteins. These genes were compared with Brassica rapa through
Arabidopsis Ensemble Orthology from the TOAST Database. Similarities were seen in alcohol
dehydrogenase, elongation factor, ethylene-responsive factor, heat-shock proteins, NAP, and
RAP2.12.
Overall, transcription profiling indicates that plants’ survival in spaceflight is dependent on
adaptive changes with gene expression. This study also indicates that there are similarities in
gene expression between Arabidopsis thaliana and Brassica rapa with comparable gene
expression. Future studies could include analyzing additional species to understand which genes
could be modified to ensure better yield of space crops amid hypoxic conditions.