Conserved plant transcriptional responses to microgravity from two consecutive spaceflight experiments

Area of Science:

• Plant biology
• Space biology
• Molecular biology

Background:

• Plants are vital for long-duration space missions.
• Understanding plant adaptation to microgravity is essential.
• Previous spaceflight experiments show inconsistent results.

Purpose of the Study:

• To investigate plant adaptation to microgravity using two spaceflight experiments (PS and PRR).
• To identify consistent gene expression patterns in microgravity.
• To evaluate the utility of onboard 1g controls.

Main Methods:

• Utilized the European Modular Cultivation System (EMCS) on the International Space Station.
• Conducted RNA-Seq analysis on shoot samples from PS and PRR experiments.
• Analyzed small RNA (sRNA) landscape in the PRR experiment.

Main Results:

• Significant overlap in differentially expressed genes between PS and PRR in microgravity.
• Upregulation of genes related to transcriptional regulation, shoot development, auxin, and light response.
• Downregulation of genes involved in defense, stress, Ca++ signaling, and cell wall modification.
• Identified specific microRNAs (miRNAs) upregulated in microgravity with downregulated target genes, many encoding chloroplast proteins.

Conclusions:

• Microgravity induces unique transcriptional changes in plants.
• Onboard 1g controls are critical for distinguishing microgravity effects from other spaceflight factors.
• Results highlight the importance of controlled experiments for understanding plant responses to space environments.