Characterization of the cellulosic enzymes from intestinal tracts of western corn rootworm, Diabrotica virgifera (Coleoptera: Chrysomelidae)

Previous studies have shown that Diabrotica virgifera virgifera is a potential source of cellulolytic enzymes based on cDNA sequences that exhibit high similarity to previously identified insect cellulases. In this study, the activities of D. v. virgifera cellulases (endoglucanases, exoglucanases and ß-glucosidases) were determined using a combination of different cellulosic substrates (carboxymethylcellulose, salicin, hydroxyethylcellulose, filter paper, p-nitrophenyl β-D-glucopyranoside and p-nitrophenyl β-D-cellobioside). These enzymes were stable at temperatures up to 50ºC and exhibit a variable pH stability range. In addition, the enzymatic assays demonstrated that there is a noticeable difference in the specific activities of cellulosic enzymes when they were evaluated in the different regions of D. v. virgifera gut. The current results show that the cellulase complex from D. virgifera represents not only an alternative source of cellulases for converting biomass to fermentable sugars but also, a potential metabolic target for insect pest control.