Plant lectins: wheat defense strategy against Hessian fly

Plants produce a variety of defense proteins, including lectins in response to attack by phytophagous insects. Ultrastructural studies reveal that binding to insect gut structures and resistance to proteolytic degradation by insect digestive enzymes are the two main prerequisites for the lectins to have deleterious effects on insects. The current study explores the effects of some dietary lectins on the growth and development of Hessian fly (Mayetiola destructor) larvae, one of the major dipteran pests of wheat. Since Hessian fly larvae are obligate parasites and cannot be cultured on an artificial diet we developed a unique in planta approach for bioassaying the lectins with the Hessian fly larvae. Here we discuss ultrastructural and transcriptional changes in the larval midgut in response to uptake of these lectins using this strategy. Assessing the toxicity of these proteins opens up the potential of engineering lectin-expressing transgenic plant lines that will confer resistance in wheat against this as well as other devastating insect pests.