Rapid analysis of insecticidal metabolites from the entomopathogenic fungus Beauveria bassiana 331R using UPLC-Q-Orbitrap MS

Abstract

Abstract Beauveria bassiana, a representative entomopathogenic fungus, is increasingly being utilized as an eco-friendly pest management alternative to chemical insecticides. This fungus produces a range of insecticidal secondary metabolites that act as antimicrobial and immunosuppressive agents. This study aimed to develop a method for the rapid analysis of these metabolites. Eight secondary metabolites (bassianin, bassianolide, beauvericin, beauveriolide Ⅰ, enniatin A, A1, and B, and tenellin) were efficiently extracted when B.bassiana-infected Tenebrio molitor larvae were ground in 70% EtOH extraction solvent and subsequently subjected to ultrasonic treatment for 30 minutes. The eight metabolites were rapidly and simultaneously analyzed using ultra-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry (UPLC-Q-Orbitrap MS). Bassianolide (20.6–51.1 µg/g) and beauvericin (63.6–109.8 µg/g) were identified as the main metabolites in B. basssiana-infected larvae, indicating that they are likely major toxins of B. bassiana. Validation of the method exhibited recovery rates in the range of 80–115% and precision in the range of 0.1–8.0%, indicating no significant interference from compounds in the matrix. The validation results satisfied the guidelines of the Association of Official Agricultural Chemists. This study also suggests that B. bassiana may employ different metabolite production strategies depending on the target insect. The findings of this study reveal an efficient and time-effective method for analyzing B. bassiana metabolites. This method not only enhances our understanding of the insecticidal mechanisms of B. bassiana but also aids in the development of biopesticide products using these fungal-derived metabolites, thereby promoting eco-friendly pest management strategies.