Progress in research on phloem-based plant resistance to piercing-sucking insects

Author of the article:FAN Yan-Zhen1** WANG Xin-Xiang2 ZHANG Yue3, 4 YAO Lu-Qin1 XIE Rui-Zhi1 ZHANG Zhi-Yong1 GUO Ho

Author's Workplace：1. Key Laboratory of Urban Agriculture in North China, Ministry of Agriculture and Rural Affairs, College of Biology, Resources and Environment, Beijing University of Agriculture, Beijing 102206, China; 2. Baoshan Animal Disease Prevention and Control Center, Baoshan 678000, China; 3. Cangzhou Academy of Agricultural and Forestry Sciences, Cangzhou 061001, China; 4. Key Laboratory of Soil Entomology in Hebei Province, Cangzhou 061001, China

Key Words：phloem-feeding, piercing-sucking insects; phloem-based defense; functional mode; regulation mechanism; insect salivary protein

Abstract：Phloem-feeding, piercing-sucking insects are one of the most destructive pests in global agricultural production. These insects, such as aphids, generally feed on tender plant tissues, including leaf undersides, young stems, and flowers. By penetrating the plant phloem and continuously ingesting phloem sap via specialized stylets, these pests consume plant nutrients and can even cause plant death. Given that plant phloem is the primary feeding site for phloem-feeding, piercing-sucking insects, it is important to investigate the mechanisms underlying the phloem-based defense (PBD) of plants against these pests. This review summarizes the functional modes of PBD (callose deposition and P protein plugging), their regulatory mechanisms (hormone signaling, transcriptional regulation, and the expression of defense-related genes), as well as the role of insect salivary proteins (elicitors and effectors) in modulating PBD. We elaborate on the interaction between plants and phloem-feeding, piercing-sucking insects from the perspective of PBD activation and insect counter-defense. This review aims to provide a theoretical basis for further understanding the defense mechanisms of plants against piercing-sucking insects, and for developing green pest management strategies based on PBD. It also offers new insights for the molecular design and breeding of insect-resistant crop varieties.