The biochemical machinery necessary for peptide synthesis, secretion, and posttranslational modification is present in every living cell. An enormous structural diversity can be generated by use of this preexisting cellular machinery. Not surprisingly, peptides are commonly used as signal molecules for intercellular communication in prokaryotes, fungi, and animals. These phytohormones are small diffusible molecules which were thought to be much better suited to penetrate the rigid cell walls between adjacent cells as compared to large peptide hormones. Research in recent years, however, has indicated that peptides may be widely used as chemical signals in plants as well. In the present work, I intend to summarize the evidence in support of this hypothesis. Cell to cell interaction is very important for the development of multicellular organization and for the function of most organ systems. Plant hormones play important roles in regulating developmental processes and signaling networks involved in plant responses to a wide range of biotic and abiotic stresses. Peptide signaling plays a greater than anticipated role in various aspects of plant growth and development. A substantial proportion of these peptides are secretory and act as local signals mediating cell-to-cell communication. Specific receptor for several peptides were identified as being memberane-localized receptor kinases, the largest family of receptor- like molecules in plants. Peptide hormones play very important role in plant signaling and plant defense.
peptide, plant hormones, plant signal, molecules
