Abstract: Phloem feeding involves special biological interactions between the herbivores and their host plants. This article reviews the types of plant defense responses, the change of plant defensive substances, signaling pathways and transcriptome studies of plant responses induced by phloem-feeding insects. The mechanisms of plant defense responses induced by phloem-feeding insects mainly include: changing plant nutritional status, producing toxic metabolites and increasing defensive proteins. Furthermore, plant defense responses are closely related to salicylic acid, jasmonic acid and ethylene signaling pathways. Plant defense responses induced by phloem-feeding insects mainly activate the salicylic acid signaling pathway, while the molecular mechanisms are not well understood. The growing genomics resources and the development of molecular biology techniques will reveal the signaling networks, the specific factors that dictate innate immunity and gene-for-gene-mediated defense to phloem-feeding insects. Understanding the plant responses induced by phloemfeeding insects will provide a better understanding of plantinsect interactions and new insights into pest management and the cultivation of pest-resistant plants.

Key words: Piercing-sucking insects, phloem-feeding insects, aphid, whitefly, induced resistance, salicylic acid signaling pathway, transcriptomics