Protein and isozyme patterns among isolates of Beauveria brongniartii with different virulence to European cockchafer larvae (Melolontha melolontha L.)

Abstract

Abstract: It was the purpose of this study to elucidate whether sodium dodecyl sulfate‐polyactylamide gel electrophoresis (SDS‐PAGE) of soluble proteins and isozyme analysis of intracellular enzymes are useful methods to distinguish between 31 Beauveria brongniartii isolates of different virulence to Melolontha melolontha larvae. Cluster and principle coordinate analysis of data from soluble proteins demonstrated a high level of intraspecific variation and little correlation with virulence to M. melolontha larvae. The isozymes of the esterase, acid phosphatase and malate dehydrogenase showed high activity and gave consistent band resolution, resulting in 18 different enzyme types, whereas the enzyme systems of the alkaline phosphatase, catalase, glutamate oxalacetate transaminase, peroxidase and superoxide dismutase were not suitable for further evaluation. Levels of intraspecific variation after isozyme analysis were lower than in total protein analysis. Although two of the four B. brongniartii isolates with the lowest virulence against M. melolontha larvae differed in their enzyme patterns from the other isolates, a clear distinction between groups of different virulent isolates was not possible. Thus, analysis of the isozyme patterns of intracellular enzymes could only be a first step in selecting more promising B. brongniartii pathotypes for development as biocontrol agents.