Relationship of Insecticidal Activity and Resistance to Proteolysis of Two Glucose/ Mannose Plant Lectins

Cleverson Diniz Freitas, Marcio Viana Ramos, Diego Pereira Souza, Jose Delano Barreto Marinho-Filho, Fabiano Moura Teixeira, Jefferson Soares Oliveira

Abstract


Purified seed lectins from the legumes Canavalia brasiliensis (ConBr) and Cratylia floribunda (CFL)were tested for insecticidal activity against Callosobruchus maculatus (Coleoptera: Bruchidae)and Dysdercus peruvianus (Hemiptera: Pyrrhocoridae). ConBr and CFL caused negative effects onlarvae of C. maculatus at levels of 1% and 2% (w/w). Time of development of C. maculatus insects,grown in artificial seeds containing both lectins, was not significantly altered, but the emergencewas slightly diminished. Both lectins were resisted to proteolysis by gut proteases of C. maculatuslarvae. Artificial diets containing 1% and 2% of ConBr or CFL caused no effect on weight and survivalof D. peruvianus nymphs. Gut proteases of D. peruvianus were able to breakdown ConBr and CFLafter 2 hours of incubation. The ability of insects to digest the proteins was correlated directly withthe deleterious effect observed.

Keywords


Carbohydrate-binding proteins, Callosobruchus maculatus, Dysdercus peruvianus, lectins.



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