All the Better to Eat You with: Identifying and Characterizing Digestive Cysteine Peptidases in Tribolium castaneum

The red flour beetle, Tribolium castaneum, is a major agricultural pest responsible for considerable loss of stored grain and cereal products worldwide. T. castaneum larvae have a highly compartmentalized gut, with cysteine peptidases mostly in the acidic anterior part of the midgut which are critical to the early stages of food digestion. We associated specific cysteine peptidase genes with digestive functions for food processing based on a comparison of gene expression profiles in different developmental stages (egg, larvae, pupae, and adult).  From this data we created a new model of food digestion in T. castaneum. Based on this model, we selected a major digestive cysteine peptidase to target via RNAi.  By monitoring gene expression with transcriptome analysis, we determined knockdown specificity, off-target effects, and digestive compensation by other digestive peptidases. This data contributes new information on digestion in an agricultural pest and will be helpful in developing targeted pest control strategies for tenebrionid insects.