Potential Insecticidal Toxins Extracted from Some Isolates of Akanthomyces

Entomopathogenic fungi (EPF) are the key elements for pest management in sustainable agriculture. Many EPFs can produce secondary metabolites with toxic effects, which playing an essential role in their pathogenicity. In this study, the metabolites of some EPFs, including three isolates of Akanthomyces lecanii species (PAL6, PAL7, and PAL8) and one isolate of A. muscarius species (AGM5), were biochemically analyzed. Extracellular metabolites were isolated from the fungal cells of the two-week-old culture of each isolate, and the chemical constituents were identified using by high-performance liquid chromatography (HPLC). During the retention times interval of 10-13 minutes, four different peaks were observed within metabolites of the isolates PAL6, PAL7, and PAL8. In the case of the AGM5 isolate, ; however, one peak was observed at 11.53 retention time. Comparative analysis showed the presence of insecticidal toxic cyclic peptides such as bassianolide within the fungal metabolites. Moreover, one peak with a new identity was detected within the metabolites from the fungal isolates of PAL6, PAL7, and PAL8 in the retention time interval of 5 minutes, from the isolate AGM5 at 11.53 retention time. The results demonstrated that the production ofproducing toxic compounds such as bassianolide by the EPF probably contributed to their insecticidal effects.