Inhibition of Eurygaster integriceps Digestive α-amylase by Enzyme Inhibitors of the Wheat Varieties; Arvand, Behrang and Hirmand

Sunn pest is most important insect pest of wheat and barley in Iran and many other countries. Plant α-amylase inhibitors showed great potential as tools to engineer resistance of crop plants against pests. In this study, the inhibitory effects of proteins inhibitors isolated from three varieties of wheat (Triticum aestivum var. Arvand and var Hirmand) and (Triticum turgidum var. Behrang) were examined on gut α-amylase for Sunn pest (Eurygaster integricepse). To do so adult insects, were dissected and their gut removed and their amylase were extracted. Proteinaceous of wheat were extracted using 0/1 M Nacl. Effect of proteinaceous extracts on amylase activity in both enzymatic assay and in gel assay using zymogram was performed. 58%, 30% and 55% inhibition presence were recorded for the Arvand and Hirmand and Behrang varieties (58%±1/5), (%30±1/5) and (55%±2/22) respectively. Enzyme electrophoresis bands were showed low enzyme activity in presence of inhibitor proteins in comparison with control (lack of inhibitor protein). In Arvand and Behrang varieties showed lower activity toward var Hirmand that confirms high inhibitory effect in Arvand and Behrang varieties toward var Hirmand. The specific activity of Sunn pest amylase was 2/85 U/mg.