Tandem Mass Tag-Based Quantitative Proteomics and Virulence Phenotype of Hemolymph-Treated Bacillus thuringiensis kurstaki Cells Reveal New Insights on Bacterial Pathogenesis in Insects

Abstract

After ingestion by a susceptible insect and damaging its midgut epithelium, the bacterium Bacillus thuringiensis (Bt) reaches the insect blood (hemolymph), where it propagates despite the host’s antimicrobial defenses and induces insect death by acute septicemia. Although the hemolymph stage of the Bt toxic pathway is determinant for the infested insects’ fate, the response of Bt to hemolymph and the latter’s role in bacterial pathogenesis has been poorly explored.

Involvement of Sep38β in the Insecticidal Activity of Bacillus thuringiensis against Beet Armyworm, Spodoptera exigua (Lepidoptera)

“…Interestingly, Bt infection altered gut bacterial composition and resulted in dysbiosis of the gut microbiota . Midgut bacteria enter the blood cavity through the perforation of the midgut caused by Bt toxin, accelerating insect death . These results indicate that Sep38 β-mediated ROS production is very important for pathogen clearance in the insect gut, and once it is damaged, pathogen infection will accelerate insect death (Figure ).…”