The biological functions of peptide signaling in plant and the advances on its utilization for crop improvement.

As the important signaling molecules in plants, peptides at femtomolar levels are recognized and bound by the corresponding plasma membrane-localized receptor-like kinases. This triggers the peptide-receptor-mediated intercellular signal transduction for regulation of the stem cell growth and proliferation, modulation of the development of plant organs (such as roots, stems, leaves, flowers, and fruits) as well as coordinating plant responses to biotic and abiotic stresses. With the advancement of in-depth research, an increasing number of studies have revealed the crucial role of peptides in regulating agronomic traits of various crops, including rice (Oryza sativa), maize (Zea mays), potato (Solanum tuberosum) and tomato (Solanum lycopersicum). These findings suggest the great potentials of utilizing the peptide signaling for genetic improvement of crops. In this review, we provide a comprehensive overview of the biological function and molecular mechanism of peptide-receptor signaling in plants, and highlight the advances in research of peptides in regulating crop yield, quality and resistance. Then, we discuss the strategies for the application of peptide signaling in crop improvement. Finally, we point out some future directions for peptide research in plant.