Circadian Regulation in Plant Growth and Development

The circadian clock in plants is an endogenous timekeeping system that orchestrates physiological and developmental processes in alignment with the daily light–dark cycle. Central to this system is a network of interlocking transcriptional feedback loops, featuring core components such as CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), LATE ELONGATED HYPOCOTYL (LHY) and PSEUDO-RESPONSE REGULATORS (PRRs). Together these factors generate self‐sustained oscillations with a period of approximately 24 hours. The clock gates key outputs—including photosynthesis, hormone biosynthesis and cell division—to specific times of day, optimising energy use and growth. Photoperiod measurement by the oscillator synchronises flowering and seasonal developmental transitions via regulators such as FLOWERING LOCUS T (FT) homologues. Beyond reproduction, circadian control extends to abiotic stress tolerance, integrating temperature and metabolic cues to modulate stomatal opening, cold acclimation and osmotic balance. These time‐of‐day programmes confer adaptive advantages by anticipating environmental changes, improving biomass accumulation, yield stability and resistance to fluctuating conditions in both natural and agricultural settings.

Research from Nature Portfolio

Recent studies have elucidated how the circadian clock modulates seasonal growth in tree species. In poplar, a quantitative model links core clock genes to daily levels of FT2, the mobile signal governing shoot apex activity. GIGANTEA acts as a circadian phase–specific inducer of FT2, while TIMING OF CAB EXPRESSION and LHY2 impose temporal repression. This mechanism narrows the activation window of FT2 under shortening days, triggering growth cessation precisely at seasonal thresholds. In Arabidopsis, a nuclear‐encoded sigma factor, SIG5, has been shown to integrate low‐temperature signals with the circadian clock. Under chilling conditions, SIG5 expression is gated by clock‐controlled bZIP transcription factors, leading to enhanced chloroplast transcription and photosynthetic performance during prolonged cold exposure. This work reveals a direct molecular link between temperature sensing and circadian gating in cold acclimation.

Circadian Regulation in Plant Growth and Development publication trend

The graph below shows the total number of articles in circadian regulation in plant growth and development across all publications each year (not limited to Nature Index journals).

Technical terms

Circadian clock: Endogenous oscillator generating ~24 h rhythms to coordinate biological processes with day–night cycles.

Photoperiodism: Regulation of developmental transitions, such as flowering, in response to daylength signals.

FLOWERING LOCUS T (FT): Mobile protein signal promoting floral induction; its expression is gated by the clock and photoperiod.

Sigma factor: Nuclear‐encoded protein that directs transcription of chloroplast genes, integrating environmental and clock signals.

Gating: Temporal restriction of physiological or molecular responses to specific phases of the circadian cycle.

References

1. New Horizons in Plant Photoperiodism. Annual Review of Plant Biology (2023).
2. Core clock genes adjust growth cessation time to day-night switches in poplar. Nature Communications (2024).
3. Low-temperature and circadian signals are integrated by the sigma factor SIG5. Nature Plants (2023).
4. Global transcriptome analysis reveals circadian regulation of key pathways in plant growth and development. Genome Biology (2008).
5. Network Discovery Pipeline Elucidates Conserved Time-of-Day–Specific cis-Regulatory Modules. PLOS Genetics (2008).
6. Circadian regulation of abiotic stress tolerance in plants. Frontiers in Plant Science (2015).