Variations in Circadian Clock Organization & Function: A Journey from Ancient to Recent

Area of Science:

• Plant biology
• Chronobiology
• Genetics

Background:

• Organisms possess innate timekeeping abilities through circadian clocks, essential for daily rhythms.
• The circadian clock, characterized by periodicity and entrainment, governs fundamental biological processes.
• While extensively studied in *Arabidopsis thaliana*, variations in clock organization and function across diverse plant systems remain underexplored.

Purpose of the Study:

• To review variations in circadian clock component organization and function across different plant types.
• To examine the role of these variations in plant adaptation to varied environmental conditions and abiotic stresses.
• To highlight the evolutionary significance of circadian clock diversity in plants.

Main Methods:

• Literature review of existing research on plant circadian clocks.
• Comparative analysis of clock component organization in various plant groups (non-flowering, marine, dicots, monocots).
• Discussion of the interaction between the circadian clock and abiotic stress response pathways.

Main Results:

• Circadian clock components display significant structural and functional diversity across plant species.
• These variations are crucial for plant adaptation and fitness in diverse environments.
• The circadian clock's interaction with abiotic stresses (temperature, light, water, salinity, nutrients) leads to significant reprogramming.

Conclusions:

• Variations in plant circadian clocks are critical for adaptation, fitness, and evolution.
• Understanding these variations and their response to abiotic stresses is key for sustainable agriculture.
• Further research is needed to elucidate the complex regulatory mechanisms, including post-transcriptional and post-translational modifications, and non-coding RNAs.