Chapter 16 Naturally occurring anti-insect proteins: current status and future aspects

Abstract

This chapter focuses on proteins that are toxic to predatory insects. A variety of structurally different proteins display anti-insect activity. They include thiol methyltransferses, lectins, arcelins, ureases, avidin, chitinases, α-amylase inhibitors, protease inhibitors, B. thuringiensis toxin, spider toxins, and scorpion toxins. They have different entomotoxic mechanisms. Lectins of fungal, monocot, legume, and other dicot origins have been shown to possess insecticidal activity. In some lectins, it has been demonstrated that carbohydrate binding and resistance to proteases in the insect gut are important for their anti-insect activity. Some arcelins, which are lectin-like proteins, may also exhibit protease resistance and anti-insect activities. Some ribosome inactivating proteins that manifest toxic effects on tumor cells and arrest protein synthesis by virtue of their N -glycosidase activity are also insecticidal. Some chitinases may exert their anti-insect activity by their enzymatic activity on chitin that is a constituent of the insect cuticle.