Abstract:  Host plants and insects have formed complex defense and counter defense mechanisms in the long-term co-evolution. In this article, we systematically reviewed the process and mechanism of the mutual defense in host plant-piercing-sucking insect interactions. The piercing-sucking insects use specialized needles to suck the sap of the host plant tissue. Plants sense insect feeding signals through cell membrane surface or intracellular receptors, and activate plant immunity through signal transduction pathways such as mitogen-activated protein kinase (MAPK) signaling pathway, plant hormone signaling pathway, calcium ion signaling pathway, transcription factor regulation, Rop/Rac GTPase signaling pathway and reactive oxygen species (ROS) pathway. To prevent further insect feeding, host plants form a strengthened physical barrier and induce the production of secondary metabolites, anti-nutritional enzymes, anti-digestive enzymes and callose deposition, and release volatiles and other defense mechanisms. In the process of “gaming” with host plants, piercing-sucking insects often use secreted salivary components during the feeding to target plant proteins. By destroying the physical barrier of host plants, or inhibiting the resistance signal transduction of host plants, or inhibiting the toxic effect of the host secondary metabolites, or by means of cross-border RNA and horizontal gene transfer, piercing-sucking insects inhibit the plant defense response and continue feeding to cause damage. In addition, based on the plant-pathogen interaction model, and combined with the research advance of the host plant-piercing-sucking insect interaction, we summarized the development of the interaction model between host plants and piercing-sucking insects. Since the host plant-insect interaction is sophisticated, a profound study on the mutual defense processes and molecular mechanisms of the host plant-piercing-sucking insect interaction will not only help deepen the understanding of their co-evolution, but also help to provide theoretical foundation and references for developing new approaches and technologies for crop insect pest control.

Key words: Host plant, piercing-sucking insect, co-evolution, defense and counter defense, interaction mechanism