Professor University of Milan Levate, Lombardia, Italy
Ichneumonid and braconid parasitic wasps colonize lepidopteran larvae and subvert their physiology to meet at best the nutritional and developmental needs of their progeny. Host regulation is mediated by components of the venom that are encoded by the wasp and its viral symbionts (Polydnaviruses - PDVs), which are a nearly untapped source of bioinsecticide molecules currently being explored to develop new plant protection tools and strategies.
Our studies in this research area allowed the identification of insect immune genes suppressed by PDVs or of PDV origin which when silenced by RNAi enhance the susceptibility of pest insects to pathogens, such as Bacillus thuringiensis (Bt). This allowed to demonstrate the key-importance of septicemia in the Bt killing activity and paved the way towards the development of bioinspired strategies of pest control aiming to develop new Bt formulations synergized by dsRNAs targeting immune genes. The rationale of this approach, aiming to enhance the impact of microbial biocontrol agents (MBA), will be presented along with the details on targeted immune genes and effective delivery strategies.
Besides improving the effectiveness of MBA-based control, these studies offer a proof-of-concept for the development of targeted, bioinspired and eco-sustainable control strategies that can enhance the ecological services provided by insect natural antagonists.