Induction of mortality on Nasutitermes corniger (Isoptera, Termitidae) by Myracrodruon urundeuva heartwood lectin

Abstract: Termites are eusocial insects that can promote severe damage in wood. The presence of lectins, carbohydrate-binding proteins that have shown entomotoxic activity, was detected in the saline extract from Myracrodruon urundeuva, a termite-resistant heartwood. The purpose of this work was to evaluate the effect of M. urundeuva heartwood lectin on termites of Nasutitermes corniger. The lectin isolated by affinity chromatography (chitin column) was submitted to trypsin treatment and analyzed for the presence of non-protein contaminants. Lectin''s effect on N. corniger was evaluated by termiticidal and repellence assays. Lectin activity was inhibited by N-acetylglucosamine monosaccharide and adsorbed on a chitin column. The lectin preparation obtained was free of secondary plant metabolites that can promote insect mortality. Contact with lectin in all concentrations induced mortality of termites. The values of LC50 were 0.248mgml−1 for workers and 0.199mgml−1 for soldiers, after 4 days. Repellence assay indicated that the lectin did not induce a rejection effect. The lectin remained active after incubation with bovine trypsin. This is the first report of lectin''s toxic effect on termites. The effect of M. urundeuva lectin on N. corniger survival points out the possibility of using this bioactive peptide to aid resistance of M. urundeuva heartwood to termites. [Copyright &y& Elsevier]