Transient Expression of Bta78 Gene in Nicotiana benthamiana Enhances Whitefly Feeding Activity

Bemisia tabaci damages crop plants by sucking plant sap and transmitting economically important viruses. For both processes, whitefly saliva plays an important role in establishing successful feeding contact. This study evaluated the effect of the Bta78 gene on whitefly survival, fecundity, and feeding activity by transiently expressing it in Nicotiana benthamiana plants using a Turnip mosaic virus (TuMV) expression vector. The Bta78 gene encodes phosphatidylethanolamine-binding protein (PEBP), previously reported as a B. tabaci salivary protein. A two-fold increase in whitefly feeding activity, measured by honeydew secretion, was observed on Bta78-expressing plants compared with green fluorescent protein (GFP)-expressing TuMV-GFP control plants. By contrast, no significant effects on whitefly survival or fecundity were detected. In this study, vitellogenin, a well-conserved protein in the insect phylum associated with insect fecundity, was used as a positive control. Whiteflies exposed to vitellogenin-expressing plants exhibited a 2-2.5-fold increase in egg production relative to those infesting TuMV-GFP control plants. To the best of our knowledge, these results provide the first evidence that the PEBP-domain-carrying salivary protein Bta78 promotes whitefly feeding.