Production of destruxins by Metarhizium strains under different stress conditions and their detection by using UHPLC-MS/MS.

Entomopathogenic fungi (EF), in particular the genus Metarhizium, have shown success in the control of insect pests. However, only a few have been commercialized mainly due to problems associated with the registration schedule, with emphasis on the lack of mandatory specific data requirements for the detection of secondary metabolites. In this study destruxin production for Metarhizium strains BIPESCO5, EAMa 01/58-Su, ARSEF 23 and ART 2825 was determined with an improved method of ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), which has shown high precision in the detection and quantification of dtxs in four culture media (CM, MM, CN2 and OSM) representing different stress conditions. Every 3 days samples were taken for analysis over 18 days that allowed detecting 15 dtxs, with dtx A and B as the most abundant. However, very significant differences among strains in dtxs production were detected, and for each strain, dtxs production was highly dependent on culture medium, which highlights that the selection of a suitable medium for strain production for the risk assessment of secondary metabolites produced by EF is mandatory. [ABSTRACT FROM AUTHOR]