Expression of stress response genes in barley Hordeum vulgare in a spaceflight environment

The transcriptome of barley Hordeum vulgare grown aboard the International Space Station was studied using microarray analysis. In the spaceflight environment, mRNA levels of over 500 genes were changed more than twofold; among them, genes of stress response proteins, in particular, heat shock proteins, pathogenesis-related proteins, and antioxidant proteins. Further analysis by real-time PCR confirmed enhanced transcription of reactive oxygen species scavenging genes. The superoxide dismutase (sod) mRNA level in the space environment was 6-fold higher than in earth conditions. The transcript levels of glutamyl transferase (gst), catalase (cat), and ascorbate peroxidase (apx) were increased in spaceflight 24, 18, and 3 times in comparison to ground control, respectively. For the first time, it has been shown that spaceflight environment can induce oxidative stress in plants.