Insecticidal activity of Arum maculatum tuber lectin and its binding to the glycosylated insect gut receptors

Mannose binding ∼50 kDa homotetrameric lectin, purified from edible Arum maculatum tuber, was analyzed through SDS−PAGE and studied for its agglutination property using rabbit erythrocytes. Cross reactivity of the purified lectin was verified through western blot using Colocasia esculantum (Family, Araceae) tuber lectin antibody. The insecticidal activity of Arum maculatum tuber lectin (ATL) was tested against two economically important sucking pests, Lipaphis erysimi and Aphis craccivora, in an artificial diet. The LC50 values for L. erysimi and A. craccivora were determined to be 21 μg/mL and 16 μg/mL, respectively. Addition of α-d-mannose in ATL-supplemented diet reduced the aphid mortality. Two major receptor proteins of ATL (∼40 kDa and ∼35 kDa) were detected from the brush border membrane vesicle (BBMV) protein of L. erysimi and A. craccivora guts, respectively, using ligand-binding assay. α-d-Mannose was found to be a deterrent to such binding of ATL to the BBMV receptors. Keywords: Arum maculatum ...