Effects of destruxin A on the trehalose content, trehalase activity and their gene expression of Bemisia tabaci

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a serious pest of agricultural crops in different regions of the world. Destruxin A (DA) is one of 39 derivatives of destruxins, which are secondary metabolites produced by entomopathogenic fungi. Due to the high insecticidal activity, DA have great application potential in biological control of B. tabaci. In order to understand the impact of destruxin A on the energy substances of the global pest B. tabaci, we measured the changes in energy substance content of the B. tabaci adults treated with DA at LC10 and LC50 concentrations after 4, 8, and 12 hours. The results revealed that DA caused varying degrees of decline in trehalose, soluble sugars, and glycogen content, indicating its ability to influence the energy substance content of whiteflies. After DA treatment, the content of trehalose in B. tabaci decreased significantly, while the activity of trehalase, a specific hydrolase for trehalose, increased significantly. Further study of the expression levels of two genes (BtTre-1 and BtTre-2) encoding trehalases in B. tabaci after DA treatment showed that the soluble trehalase gene, BtTre-1, was induced in both low and high concentrations of DA, while the membrane-bound trehalase gene, BtTre-2, did not show significant changes in expression level.