Plant Circadian Clocks: Unravelling the Molecular Rhythms of Nature
Adil Rahim Margay *
ICAR-National Institute for Plant Biotechnology, New Delhi, 110012, India.
Suhail Ashraf *
Faculty of Biology, CeBiTec-Center for Biotechnology, Bielefeld University, Bielefeld, 33615, Germany.
Nusrat Fatimah
Division of Agricultural Entomology, Faculty of Agriculture, Sher-e-Kashmir University of Agricultural Sciences and Technology, Srinagar, 190006, India.
Saliah Gul Jabeen
Division of Genetics and Plant Breeding, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, 190006, India.
Mansoor Showkat
Department of Plant Biotechnology, University of Agricultural Sciences, GKVK, 560065, Bengaluru, India.
Krishna Nayana R U
Department of Plant Biotechnology, Centre for Plant Biotechnology and Molecular Biology, Kerala Agricultural University, Thrissur, 680654, Kerala, India.
Sampatirao Dilip
ICAR-National Institute for Plant Biotechnology, New Delhi, 110012, India.
Sudhakar Reddy Basu
Genetics and Plant Breeding ICAR-Indian Agricultural Research Institute, 110012, New Delhi, India.
K. A. Aswathy
Department of Plant Biotechnology, Centre for Plant Biotechnology and Molecular Biology, Kerala Agricultural University, Thrissur, 680654, Kerala, India.
*Author to whom correspondence should be addressed.
Abstract
The circadian clock is a fundamental biological mechanism that allows organisms to synchronize their internal processes with the external environment, thereby optimizing growth, development, and physiology. In plants, circadian rhythms govern various aspects of their life cycle, including germination, leaf movement, flowering, and responses to environmental cues such as light and temperature. Understanding the molecular mechanisms underlying plant circadian clocks is essential not only for elucidating fundamental principles of plant biology but also for applications in agriculture and biotechnology. This review delves into the intricate molecular networks that comprise plant circadian clocks, focusing on key components and their interactions. At the core of these clocks are transcription-translation feedback loops (TTFLs) involving a set of clock genes. The central oscillator, composed of genes such as CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), LATE ELONGATED HYPOCOTYL (LHY), TIMING OF CAB EXPRESSION 1 (TOC1), and PSEUDO-RESPONSE REGULATOR (PRR) genes, drives rhythmic expression of downstream clock-controlled genes (CCGs). The interplay between positive and negative regulators within the TTFLs generates robust oscillations with a period of approximately 24 hours. Additionally, post-translational modifications, protein-protein interactions, and chromatin remodeling contribute to fine-tuning the circadian system, allowing plants to adapt to changing environmental conditions. Light perception through photoreceptors such as phytochromes and cryptochromes plays a crucial role in entraining the circadian clock to external cues, ensuring synchronization with the day-night cycle. Furthermore, recent advancements in omics technologies, including genomics, transcriptomics, proteomics, and metabolomics, have provided unprecedented insights into the complexity and plasticity of plant circadian clocks. Integration of multi-omics data has facilitated the construction of comprehensive regulatory networks and computational models, enabling predictive understanding of clock function and behavior under diverse conditions. Overall, unraveling the molecular rhythms of plant circadian clocks not only enhances our knowledge of fundamental biological processes but also holds promise for improving crop productivity, stress resilience, and sustainability in agriculture through targeted manipulation of clock components and their associated pathways. Future research endeavors will undoubtedly continue to unveil the intricacies of these fascinating timekeeping mechanisms, further enriching our understanding of the molecular rhythms of nature.
Keywords: Biotechnology, molecular rhythms, crop productivity, biological mechanism