Validamycin reduces the transmission of Tomato chlorotic virus by Bemisia tabaci

Bemisia tabaci (Gennadius), commonly known as whitefly or sweet potato whitefly, causes feeding-related injuries to plants, and transmits more than 200 different plant viruses, including Tomato chlorosis virus (ToCV). Control of B. tabaci is therefore one of the key measures in the comprehensive prevention and control of ToCV outbreak in tomato fields. Many insects rely on the hydrolysis of trehalose, broken down by the enzyme trehalase, to power their flight and other life-sustaining activities. B. tabaci encodes just one trehalase, making it an attractive target. In this study, the mechanism underlying the involvement of trehalase in the transmission of ToCV by B. tabaci was investigated. Also, the effect of the trehalase inhibitor, validamycin, on ToCV transmission was assessed. Our results showed that trehalase activity was upregulated in B. tabaci fed on ToCV-infected tomato plants. Treating B. tabaci with validamycin decreased the trehalase activity, and significantly reduced its transmission of ToCV. Validamycin treatment also inhibited the flight and feeding ability of B. tabaci. These results indicate that proper function of trehalase is required by whitefly to transmit ToCV with high efficiency. These provides an important theoretical basis for targeting whitefly trehalase as one way to control ToCV transmission.