Endogenous peptide elicitors in higher plants

► Host-derived molecules called endogenous elicitors induce and amplify defense responses in higher plants. ► Five families of endogenous peptide elicitors have been found thus far. ► The endogenous peptide elicitors share downstream signaling mechanisms with microbe-associated molecular patterns (MAMPs). Plant defense responses against invading organisms are initiated through the perception of molecules associated with attacking microbes and herbivores by pattern recognition receptors. In addition to elicitor molecules derived from attacking organisms, plants recognize host-derived molecules. These endogenous elicitors induce and amplify the defense responses against invading organisms both locally and systemically. Several classes of plant-derived molecules elicit defense, including cell wall fragments and peptides. Endogenous peptide elicitors have been discovered in species across the plant kingdom, and their role regulating immunity to both herbivores and pathogens is becoming increasingly appreciated. In this review, we will focus on the five known endogenous peptide elicitor families, summarize their properties, and discuss research goals to further understanding of plant innate immunity.