|Quimby Jr, Paul|
Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: 1/1/2003
Publication Date: 7/26/2003
Citation: BON, M., HURARD, C., QUIMBY JR, P.C., FARGUES, J., MEIKLE, W.G., MERCADIER, G., VAUGHAN, L. DEVELOPMENT OF POTENTIAL METARHIZIUM BIOCONTROL AGENTS: INSIGHTS FROM MOLECULAR DATA. SOCIETY FOR INVERTEBRATE PATHOLOGY ANNUAL MEETING. 2003. Interpretive Summary: Problem. Metarhizium is a genus of fungi pathogenic to insects that is often considered for use in biopesticides. However, before the fungus can be considered for use in a commercial product, the strains need to be identified. This kind of fungus is difficult to analyze using most common techniques, so special methods need to be used. Approach. Several strains of the fungus were collected from different insects in Senegal, West Africa. Part of the DNA was sequenced to determine the species, and other techniques were used to investigate how different the strains were. Impact. All the fungal strains were from the same subspecies of fungus. The information on the identity and relatedness of the different strains is important for commercial reasons, such as patenting a particular strain, identifying the strain after it has been sprayed in a field, and for maintaining quality control of the product. This work contributes to a growing body of knowledge about that fungus.
Technical Abstract: Developing and bringing a mycoinsecticide to market is a multi-tiered process that includes, the identity authentication of the strain, fingerprinting development for environmental monitoring and patent registration. The limited potential of conventional strain typing in the hyphomycete genus Metarhizium, using classical criteria, such as morphological and behavioral characteristics has led to a more systematic genetic assessment of these fungi these past ten years. In this study, we selected different molecular markers based on the specific characteristics of the West African Metarhizium isolates tested and on the type of information necessary to evaluate each particular step in the developmental process of a biopesticide. The isolates originated from different hosts and geographical areas in Senegal. Sequence analysis of the ribosomal DNA (rDNA) internal transcribed spacer (ITS) allowed the classification of these isolates into the Metarhizium anisopliae var acridum group only. At this intraspecific level, ITS and 28S rDNA region analysis detected little or no variation. Genetic relatedness of these isolates was assessed by Random Amplified Polymorphic DNA (RAPD) and subsequently by Amplified Fragment Length Polymorphism (AFLP) analyses. Patterns generated by both methods showed extensive polymorphism and the isolates were easily differentiated. However, no close correspondence has been established between the clustering of these isolates and their host or ecological origins. Ultimately, some of the RAPD markers will be converted to SCAR markers for the production of diagnostic assays which will contribute markedly toward developing a quality control system and would allow post-release monitoring of these commercially important isolates.