Objective  The protein-protein interaction networks (PPINs) was applied to decipher the protective mechanism of tea plants in resisting the invasion by insects.

  Method  RNA-seq was used to determine if a Camellia sinensis cv. Niaowang plant was infested by Empoasca vitis Gothe. PPINs of differential expression genes (DEGs) between 0 h and 12 h as well as 0 h and 24 h after the infestation were constructed based on Interolog.

  Result  There were 212 PPIs between 0 h and 12 h, 3 551 PPIs between 0 h and 24 h, and 3 605 PPIs in the merged network. The topological properties of the PPINs showed the degree of the protein distribution following the power-law model, and hence, their functions predictable. It was found that DEGs mainly partook in the plant-pathogen interactions, plant hormone signal transduction, DNA base excision repair, nucleotide excision repair, mismatch repair, linolenic acid and alpha-linoleic acid metabolism, and other biological processes through GO and KEGG analysis. Furthermore, the tea leaves that were infected for 24 h would require greater amounts of PPIs than those affected for 12 h to develop the defense mechanism to ward off the ill-effect brought by Empoasca vitis Gothe.

  Conclusion  Tea plants mainly resist the invasion of Empoasca Vitis through the three differential genes to promote the corresponding interaction, and when tea plants continue to be invaded, more interactions will be initiated, or various secondary metabolites will be produced to resist pests. To resist the invasion of Empoasca Vitis, tea plant mainly promoted the PPIs of three differential genes. When invasion continuing, more interactions would be initiated, and various secondary metabolites would be produced to resist pests.