Abstract: The role of saliva protein of Empoasca onukii in the formation of “Hopperburn” symptom in tea plants has not been studied to date. In this paper, the double-layer parafilm clamping nutrient solution method and a simple self-made saliva collection device were developed to collect the watery saliva of E. onukii adults. The proteins were then extracted from the watery saliva using SDT splitting method and FASP (Filter-Aided Sample Preparation) enzymatic hydrolysis method, and then watery saliva proteins were detected by LC-MS/MS. The results showed that a total of 107 peptides and 92 proteins were identified, which could be divided into 7 groups according to their functions, including enzymes, transporter proteins, ion-binding proteins, regulatory proteins, cytoskeletal proteins, non-enzymatic proteins and uncharacterized proteins. In addition, the collected and purified salivary proteins were used to treat the mechanically damaged tea leaves and make comparison with the pure mechanically damaged leaves, the pure saliva-treated leaves, the serum protein treated leaves and E. onukii adults infested leaves. The results show that the saliva protein-treated leaves had the same trends as the leaves damaged by leafhopper, with “Hopperburn” symptoms appearing at 48 h of treatment. While no such symptoms appeared in the other treatments. This study provided some basic information for further understanding of saliva composition of E. onukii and the interaction mechanism between leafhopper saliva protein and tea plants.

Key words: Empoasca onukii, watery saliva, protein, tea plant, Hopperburn