Target of rapamycin (TOR) gene is vital for whitefly survival and reproduction

The whitefly Bemisia tabaci (Gennadius) is a devastating polyphagous pest that causes significant losses in several economically important crops worldwide. Although chemical control is the fastest management strategy, insecticide resistance development poses a greater constraint in whitefly management. In this study, we used RNA interference (RNAi) technique to understand the role of target of rapamycin (TOR) gene in whitefly. In insects, TOR plays a crucial role in cell growth, metabolism, proliferation, and reproduction. Although sequence analyses of TOR revealed 95 nucleotides different in TOR gene sequence compared to predicted sequence (GenBank accession no. XM019060193.1), but this led to synthesis of only two different amino acids at positions 1448 and 1768. Phylogenetic analysis of amino acid sequence revealed that TOR gene of B. tabaci, Acrythosiphum pisum and Nilaparvata lugens were more closely related to each other and were clustered together. Oral feeding of artificial diet containing dsRNA viz 2.0, 1.0, 0.5, 0.1 μg/μl corresponding to TOR gene to adult whitefly resulted in 42.5% adult mortality, reduced fecundity i.e. 36.57 eggs per female, and 62.50% total nymphal mortality in the next generation. The qRT-PCR analysis confirmed the downregulation of TOR gene expression in adult whiteflies upon dstor feeding. These results suggest that TOR gene significantly regulates the survival and reproduction in whitefly and can be a potential RNAi target for insect management.