GI-CO-FT confers microgravity response through Potential Regulatory Modules of Arabidopsis plants grown in Space

Abstract Our previous studies suggested that FLOWERING LOCUS (FT) can serve as a central hub, integrating microgravity signals into the photoperiodic flowering pathway in Arabidopsis. However, the exact mechanisms remain unclear. In this study, we present findings from our recent experiments on the Chinese Space Station. Transcriptomic changes of space-grown plants, including wild-type (WT), gigantea (gi) mutant, CONSTANS overexpressing plants (35S:CO), and transgenic plants expressing FT with the green fluorescent protein gene controlled by a heat shock-inducible promoter (pHSP:GFP;pHSP:FT, FG), were compared with their ground-based controls. Analysis revealed a conserved transcriptional response signature primarily across the genotypes investigated. We pinpointed a new set of microgravity-responsive genes with a significant enrichment in flowering controlling pathways. In addition, this study highlighted bZIP, bHLH, BES1, and SBP family transcription factors, which are known integrators of hormone, light, and photoperiodic signals, as key mediators of the microgravity response in space.