Glucose–TOR signalling reprograms the transcriptome and activates meristems
Meristems encompass stem/progenitor cells that sustain postembryonic growth of all plant organs. How meristems are activated and sustained by nutrient signaling remains enigmatic in photosynthetic plants. Combining chemical manipulations and chemical genetics at the photoautotrophic transition checkpoint, we reveal that shoot photosynthesis-derived glucose drives target-of-rapamycin (TOR) signaling relays through glycolysis and mitochondrial bioenergetics to control root meristem activation, which is decoupled from direct glucose sensing, growth-hormone signaling and stem-cell maintenance.
Surprisingly, glucose–TOR signaling dictates transcriptional reprogramming of remarkable gene sets involved in central and secondary metabolism, cell cycle, transcription, signaling, transport and protein folding. Systems, cellular and genetic analyses uncover TOR phosphorylation of E2Fa transcription factor for an unconventional activation of S-phase genes, and glucose-signaling defects in e2fa root meristems. Our findings establish pivotal roles of glucose–TOR signaling in unprecedented transcriptional networks wiring central metabolism and biosynthesis for energy and biomass production, and integrating localized stem/progenitor-cell proliferation through inter-organ nutrient coordination to control developmental transition and growth.
Meristems: A meristem is a tissue in plants made of dividing cells. They are in parts of the plant where growth can take place. Meristematic cells have the same function for plants as stem cells have for animals. They are incompletely or not at all differentiated, and are capable of continued cell division.