Plant Peptide Hormones and Plant Development

Peptide hormones play vital roles as precise regulators of plant growth and development, controlling a variety of morphological processes, including root architecture, shoot formation, and reproductive organ development. Unlike conventional phytohormones, peptide hormones function as short signaling molecules synthesized as precursor proteins that undergo posttranslational modifications (PTMs) before binding to receptor-like kinases (RLKs) at the cell surface. These unique signaling pathways facilitate cell-to-cell communication, enabling plants to adapt dynamically to developmental cues and environmental changes. This chapter provides a comprehensive exploration of the critical roles of peptide hormones such as CLAVATA3/ESR-related (CLE), C-terminally encoded peptide (CEP), rapid alkalinization factor (RALF), phytosulfokine (PSK), and inflorescence deficient in abscission (IDA) in regulating plant morphology. Specific focus is given to their contributions to stem cell maintenance, modulation of root architecture, leaf morphogenesis, and the development of reproductive organs. Furthermore, the chapter delves into the molecular mechanisms underlying peptide hormone perception and signal transduction, emphasizing the function of receptor-like kinases and their downstream signaling cascades. Insights into how peptide hormones regulate the division and differentiation of plant stem cells and coordinate root development are discussed, shedding light on one of the most intriguing challenges in developmental biology, understanding the precise balance between stem cell maintenance and cell differentiation.