Molecular interactions between entomopathogenic fungi and their insect host: insights into both cuticle and hemolymph battlefield

N. PEDRINI

Simposio; International symposium of fungal stress 2017; 2017

Entomopathogenic fungi invade their insect hosts by penetrating through the cuticle, and then colonize and proliferate throughout the host by replicating as hyphal bodies. To help breaching the insect cuticle, fungi produce a variety of degrading enzymes; and during the invasive process many strains secrete toxic compounds (mainly secondary metabolites) that facilitate fungal invasion. After microbial invasion, insects trigger two types of innate immune reactions: the cellular and the humoral responses. The latter includes the induction of several antimicrobial peptides (AMPs), lectins, and the prophenoloxidase cascade. Transcription of AMPs is regulated mainly by the Toll signal transduction pathway; the resulting peptides are then secreted into the hemolymph to prevent microbial proliferation. It is well known that an increased sensitivity to oxidative stress both on the conidial germination level and during host invasion is triggered in fungal cells to cope this situation. In this presentation, several components involved in an arms race between insects and fungal pathogens will be described, and some molecular mechanisms involved in such interaction will be discussed.