The effect of Proteinaceous extract of triticale on α-amylase activity of tomato leaf miner, Tuta absoluta Meyrick (Lep.: Gelechiidae)

The Tomato leaf miner is a polyvoltine pest native to South America and is a universal threat to tomato. This pest was first reported from Orumieh but nowadays it has been reported from all tomato fields of Iran. In order to control this pest, various pesticides including organophosphorous and pyrithroid insecticides are used continuously which caused the insect to develop resistance, contamination of products to pesticides residue and contamination of the environment. Thus, the aim of the current study was to study the effect of semi-purified proteinaceous extract of triticale seeds on α-amylase activity of the insect. Seed proteinaceous extract was obtained by NaCl solution and it was semi-purified using ammonium sulfate. Enzyme assay indicated that the insect amylase inhibition is dependant to the extract dose which is used i.e. with increasing inhibitor dose the amount of enzyme inhibition increased. For example, when 0.5 µg seed extract protein was used only 31% enzyme inhibition was achieved and when 8.0 µg seed extract protein was used 66% enzyme inhibition was obtained. In monitoring pH it was found that the highest inhibition was obtained at pH 8.0 and beyond this pH the amount of enzyme inhibition reduced. Gel assay confirmed our enzyme assay results which were done by Elisa reader instrument i.e. with increasing inhibitor concentration amylase band intensity decreased.