摘要：SummaryBrassinosteroids (BRs) regulate a variety of physiological processes in plants via extensive crosstalk with diverse biological signaling networks. Although BRs are known to reciprocally regulate circadian oscillation, the molecular mechanism underlying BR-mediated regulation of circadian clock remains unknown. Here, we demonstrate that the BR-activated transcription factorbri1-EMS-SUPPRESSOR 1 (BES1) integrates BR signaling into the circadian network in Arabidopsis. BES1 repressed expression ofCIRCADIAN CLOCK-ASSOCIATED 1(CCA1) andLATE ELONGATED HYPOCOTYL(LHY) at night by binding to their promoters, together with TOPLESS (TPL). The repression ofCCA1andLHYby BR treatment, which occurred during the night, was compromised inbes1-koandtpl-8mutants. Consistently, long-term treatment with BR shortened the circadian period, and BR-induced rhythmic shortening was impaired inbes1-koandtpl-8single mutants and in thecca1-1lhy-21double mutant. Overall, BR signaling is conveyed to the circadian oscillator via the BES1/TPL-CCA1/LHY module, contributing to gating diurnal BR responses in plants.Graphical AbstractDisplay OmittedHighlights•Circadian rhythm is shortened in the presence of phytohormone BR•BR signaling is relayed to circadian clock through BES1•BES1/TPL complex binds toCCA1/LHYpromoter in the dark, repressing expression•The BES1/TPL-CCA1/LHY module shapes circadian gating of BR signalingChronobiology; Plant Biology
