Japanese beetle, (Popillia japonica) midgut proteins–targets for controlling infestation

The Japanese beetle, Popillia japonica an introduced scarab, has become the most widespread and destructive pest of over 300 species of agriculturally important plants in the eastern United States. An estimated $460 million is lost each year for direct control costs in US. Establishment of the P. japonica in the western US could result in enormous economic loss. Traditionally, both adult and larval stages are targets for substantial chemical insecticide usage. Despite ongoing regulatory efforts, the P. japonica remains a threat as an invasive species and new and innovative tools are required to identify potential new target for control. We describe here preliminary yet novel systematic work to discover genes involved in midgut physiology of the P. japonica which may hold the key to controlling this pest. Sequencing of the midgut cDNA library revealed open reading frames for Serine protease, mucin-like peritrophin, peritrophin and GSTs. In this study we demonstrate that by activating the RNAi pathway through injection of dsRNA successfully knocked down the target gene expression in the P. japonica. We also show that we successfully cloned the mucin-like peritrophin and Serine protease genes into a bacterial expression vector to express the recombinant proteins for further functional analysis. The functional characterization of mucin like Peritrophin and Serine protease proteins will be discussed in this presentation.