Transcriptional changes at different developmental stages of rice (Oryza sativa L.) following lunar orbit flight

Plants are regarded as a core component of the life support system for crewed space missions, particularly in deep-space endeavors such as lunar and Martian missions. Therefore, understanding the responses of plants to deep-space flight is considered essential. Japonica rice dry seeds (Oryza sativa L.) were carried aboard the Chang'e 5 spacecraft on a flight to the lunar orbit for 23 days. Following their return to Earth, these seeds were planted and cultivated until the tillering and heading stages. Through comparative transcriptomic analysis with the ground control, it was found that rice plants exhibited a significantly higher number of differentially expressed genes (DEGs) during the tillering stage after lunar orbital flight compared to the heading stage, with distinct transcriptional regulatory patterns observed between the two developmental stages. During the tillering stage, dysregulated biological pathways included starch and sucrose metabolism, glycolysis/gluconeogenesis, amino sugar and nucleotide sugar metabolism, plant hormone signal transduction, and cellular wall organization and biogenesis. These pathways also interacted with each other in a complex pattern. During the heading stage, pathways were enriched in glutathione metabolism and photosynthesis. Additionally, certain biological pathways related to defense, development, and secondary metabolism were represented in both developmental stages. In summary, our research reveals stage-specific differences in transcriptional response patterns in rice following lunar orbital flight.