Peptides of the Innate Immune System of Plants. Part I. Structure, Biological Activity, and Mechanisms of Action

Abstract

A plant immune system is able to rapidly react in response to changes in environmental conditions and provides protection against stress, pathogens, and insects. In the case of infection, plants synthesize many pathogenesis-associated compounds, including various peptides. These peptides not only have the antimicrobial activity and enhance each other’s action but participate in a complex of defense strategies as well. Peptide factors of the plant’s innate immune system have a diverse structural organization and exhibit a wide spectrum of biological activities, including antimicrobial, antiviral, antitumor, insecticidal, antiinflammatory, antiproliferative, mitogenic, and analgesic. Some of them take part in binding and transfer of lipids, whereas the others exhibit the properties of ion-channel blockers or inhibitors of proteases and α-amylases but have no toxic effect on their own and mammalian cells. Some parts of plant peptides are clinically significant food or pollen allergens. All the abovementioned facts make them attractive objects for a detailed investigation and possible practical application to various aspects of human life. This review summarizes data on a diversity of structures, biological activity, and mechanisms of the antimicrobial action of the peptides of the plant’s innate immune system.