Molecular Dynamics of Cytokinin Signaling Pathways in Plant Growth, Development, and Stress Responses: An Integrative Review
1. Cristina Bautista, University of the Philippines, Manila, Student, Philippines
2. Pamela Frauline, University of the Philippines, Manila, Lecturer, Philippines
Cytokinins (CKs) are essential phytohormones regulating plant growth, development, and adaptive responses to environmental stress. Over the past two decades, substantial progress has been made in understanding cytokinin perception, signal transduction, receptor-mediated control of plant morphology, and their interactions with other hormonal and stress‐response pathways. This review synthesizes findings from foundational and contemporary studies to provide a comprehensive overview of cytokinin signaling, including histidine kinase receptors, multi-step phosphorelay pathways, cytokinin response factors (CRFs), and downstream transcriptional networks. The roles of cytokinin signaling in shoot and root growth, leaf senescence, seed germination, organogenesis, and metabolism are explored with reference to key genetic studies in Arabidopsis and maize. Moreover, the review examines the molecular mechanisms of cytokinin-mediated abiotic and biotic stress responses, with particular emphasis on receptor AHK1/ATHK1 function in drought and salinity signaling, and hormone cross-talk during stress adaptation. Current research trends highlight the importance of integrating cytokinin networks with abscisic acid (ABA), ethylene, and other hormonal pathways to fine-tune plant physiological responses. The review concludes by discussing gaps in current knowledge, potential applications in crop improvement, and future research directions aimed at manipulating cytokinin signaling for enhanced plant productivity and resilience.
Cytokinin signaling Histidine kinase receptors AHK1 AHP proteins Type-A response regulators Type-B response regulators Abiotic stress signaling
Cytokinin signaling represents a central regulatory framework that profoundly shapes plant growth, developmental patterning, and responses to environmental challenges. Through its network of membrane-localized receptors, multi-step phosphorelay elements, and transcriptional regulators such as CRFs, cytokinin activity governs a wide spectrum of physiological processes—from shoot morphogenesis and nutrient allocation to stress adaptation and regenerative capacity.
The growing body of research has revealed cytokinin pathways to be highly dynamic, integrating internal developmental cues with external environmental signals. Their interaction with other hormonal systems, including auxin, ethylene, and abscisic acid, forms an intricate crosstalk that fine-tunes plant performance under both optimal and adverse conditions. This interconnectedness highlights cytokinin signaling not as an isolated pathway but as a pivotal hub coordinating multiple layers of plant biology.
Harnessing and modifying cytokinin-mediated processes opens significant opportunities for improving crop resilience, optimizing yield, and enhancing the efficiency of tissue culture and regeneration technologies. As studies continue to uncover the diversity of receptor functions, species-specific signaling variations, and downstream transcriptional networks, a more comprehensive understanding will emerge. This knowledge will ultimately support innovative strategies for sustainable agriculture and long-term food security.
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The authors did not receive any specific grants from funding agencies in the public, commercial, or non-profit sectors for the research, authorship, and/or publication of this article.
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The authors declare no conflicts of interest related to this study.
I acknowledge the support and expertise of those who helped with this research and manuscript, and thank the peer reviewers for their valuable insights.
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