Metabolomics of the interaction between a consortium of entomopathogenic fungi and their target insect: Mechanisms of attack and survival

Abstract

One of the most concerning pests that attack strawberries in Brazil is Duponchelia fovealis (Zeller), a non-native moth with no registered control methods to date. Our group recently observed that a fungal consortium formed by two strains of Beauveria bassiana (Balsamo) increased the mortality of D. fovealis more than inoculation with each strain on its own. However, the molecular interaction between the fungal consortium and the caterpillars is unknown. Thus, in this work, we sought to pioneer the evaluation of the molecular interaction between a fungal consortium of B. bassiana and D. fovealis caterpillars. We aimed to understand the biocontrol process involved in this interaction and the defense system of the caterpillar. Seven days after D. fovealis were inoculated with the consortium, the dead and surviving caterpillars were analyzed using GC-MS and LC-MS. Some of the metabolites identified in dead caterpillars have primarily antioxidant action. Other metabolites may have insecticidal potential, such as diltiazem-like and tamsulosin-like compounds, as well as 2,5-dimethoxymandelic acid. In surviving caterpillars, the main mechanisms are pro-inflammatory from 2-Palmitoylglycerol metabolite and the antifungal action of the metabolite Aegle marmelos Alkaloid-C. The metabolites identified in dead caterpillars may explain the increased mortality caused by the consortium due to its antioxidant mechanism, which can suppress the caterpillars' immune system, and insecticide action. In surviving caterpillars, the main resistance mechanisms may involve the stimulus to the immunity and antifungal action.

Keywords: Beauveria bassiana; Biological control; Caterpillar; Duponchelia fovealis; GC–MS; LC-MS.