Submitted to: International Coloquim on Invertebrate Pathology and Microbial Control
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2002
Publication Date: September 1, 2002
Citation: CASTRILLO, L.A., VANDENBERG, J.D., GRIGGS, M. RISK ASSESSMENT OF GENETIC RECOMBINATION BETWEEN INTRODUCED AND INDIGENOUS STRAINS OF BEAUVERIA BASSIANA IN AGRICULTURAL FIELDS. INTERNATIONAL COLOQUIM ON INVERTEBRATE PATHOLOGY AND MICROBIAL CONTROL. 2002. v. 35. Abstract p. 99. Technical Abstract: As part of our research on the fate of introduced strains of the entomopathogenic fungus Beauveria bassiana, we are conducting a study on the risks of genetic recombination between mass-released and indigenous strains in agricultural fields. Using nitrate non-utilizing (nit) mutants, we assessed vegetative compatibility groups (VCG) among strains of B. bassiana representing naturally occurring strains collected throughout the US and strains, like GHA, that have been mass released as biological control agents against insect pests. Genetic similarity among these strains was analyzed using randomly amplified polymorphic DNA (RAPD) markers. Our data revealed a group of genetically similar strains isolated from Colorado potato beetles (CPB) from the northeastern part of the US and from Quebec and Ontario, Canada, belonging to the same VCG. Co-inoculations of CPB larvae with nit mutants revealed heterokaryon formation only between strains of the same VCG, suggesting that this self/non-self recognition system is an effective barrier preventing genetic exchange between dissimilar strains in the field. Heterokaryons were screened initially by their prototrophic growth on minimal medium and confirmed by analyses using molecular markers. Further studies are being conducted to assess the stability of these heterokaryons and the frequency of their formation.