The Reticulitermes flavipes (Kollar) peritrophic matrix: A promising target for termite pest management

The peritrophic matrix (PM) is a non-cellular structure that lines the gut of most insects. Because of its close involvement in digestive processes and its role as a barrier against pathogens and toxins, the PM is an attractive target for pest management strategies. The objectives of this study were to (1) identify the genes that encode for the main components of Reticulitermes flavipes PM, (2) to reduce the expression of those genes by means RNAi and (3) to evaluate the susceptibility of R. flavipes to dietary xenobiotics and pathogens after altering the structural integrity of the PM. A chitin synthase gene (RfCHSB) and two peritrophins (RfPMP2-III and RfPMP3-IV) were selected as targets for RNAi. Force feeding termites with 55 ng and 100 ng of long dsRNAs, targeting RfCHSB and RfPMP3-IV respectively, resulted in the highest gene silencing efficiency. RfCHSB expression was reduced by 3.3-fold, whereas the transcript level of RfPMP3-IV was decreased by 10-fold. Force feeding of 100 ng/termite of a long dsRNA reduced the expression of RfPMP2-III by 1.43-fold. Challenging termites with imidacloprid, chlorantraniliprole and noviflumuron, after silencing RfCHSB, significantly increase termite mortality. Force feeding termites a dsRNA cocktail, targeting RfCHSB, RfPMP2-III and RfPMP3-IV, cause the highest significant increase in termite mortality after challenging the insects with imidacloprid. This results demonstrates the viability of the R. flavipes PM as a target in termite pest management.