Potential regulatory modules to integrate microgravity signals into flowering pathways in Arabidopsis thaliana grown in space

Our previous studies suggested that FLOWERING LOCUS (FT) can integrate microgravity signals into the photoperiodic flowering pathway in Arabidopsis. However, the exact mechanisms remain unclear. In this study, we carried out transcriptomic analysis of wild-type (WT), gigantea (gi) mutant, CONSTANS overexpressing (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) grown on the Chinese space station in comparison with their ground controls. The findings revealed that transcriptional microgravity response signature was not only conserved across the GI-CO-FT module disruption genotypes and the WT, but also displayed GI-CO-FT module disruption specific associated responses. Transcription factors belonging to the ERF, bZIP, bHLH, and BES1 families were significantly overrepresented among the GCC- and CACGTG-elements across GI-CO-FT specific microgravity responsive genes, suggesting that disruption of GI-CO-FT module could influence plant response to microgravity through integration pathways.