Preliminary data on cellulase encoding genes in the xylophagous beetle, Hylotrupes bajulus (Linnaeus)

Hylotrupes bajulus (Linnaeus) (Coleoptera, Cerambycidae), a wood-boring beetle attacking softwood, utilises both wood starch and cellulose as food. The fibre is digested in variable percentages, depending on the starch content. A role for symbiotic bacteria was presumed as well as the presence of endogenous cellulases. The aim of our investigation was to verify the presence of endogenous endoglucanase genes in H. bajulus larvae. After performing an online search, three sequences for the endoglucanases of the class GHF5 and four for the endoglucanases of the class GHF45 were recovered and aligned in order to develop some primers on the most conserved regions and try the amplification of the genes in H. bajulus. Seven degenerated primers for GHF5 endoglucanase and five for GHF45 endoglucanase were tested. By using two different primer combinations we obtained two fragments: both of them showed homology with significant identity with insect endoglucanases of the GHF45 family available online, and one also with microbial cellulases. The first fragment is undoubtedly of endogenous origin while we cannot exclude that the second one is of microbial origin. No results were obtained for the endoglucanase of the class GHF5.