Carbon utilization pattern as a potential quality control criterion for virulence of Beauveria brongniartii

The registered entomopathogenic fungus Beauveria brongniartii (BIPESCO 2) was tested for its virulence after one, five and 10 times sub-culturing on four types of selective synthetic nutrient media. Bioassays with third instar Melolontha melolontha larvae showed that sub-culturing negatively affects the virulence of the fungus after 10 transfers. With the Biolog SF-P2 and Biolog SF-N2 microtiter plate systems the sub-cultivated B. brongniartii conidia were monitored for any change in the carbon utilization pattern of 128 carbon sources. With the help of Spearman's rank correlation, principal components analysis and canonical correspondence analysis, respectively, six carbon sources were identified as potential virulence indicators for BIPESCO 2 (pyruvic acid, maltose, glycyl-L-glutamic acid, malonic acid, glucuronamide and phenylethylamine). The Biolog microtiter plate system is suggested as a simple and inexpensive test-system for virulence determination of B. brongniartii strain BIPESCO 2 in routine quality control.