Submitted to: Fungal Genetics Newsletter
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2003
Publication Date: April 1, 2003
Citation: CASTRILLO, L.A., VANDENBERG, J.D., GRIGGS, M. EVALUATING THE LIKELIHOOD OF GENETIC RECOMBINATION BETWEEN INTRODUCED AND INDIGENOUS STRAINS OF THE ENTOMOPATHOGENIC FUNGUS BEAUVERIA BASSIANA IN AGRICULTURAL FIELDS. FUNGAL GENETICS NEWSLETTER. 2003. v. 50. Abstract p. 453. Technical Abstract: The fungal pathogen Beauveria bassiana is widely used as a mycoinsecticide for control of several insect pests, providing a biological alternative to synthetic chemical insecticides. A key advantage for microbial agents is their potential to replicate and persist in the environment, offering continued suppression of insect pest populations. However, exploiting this advantage is commensurate with the need to determine the impact of mass releases of this fungus on non-target organisms and to assure safety and long-term efficacy. To date, no information is available on the potential for genetic recombination between introduced and indigenous strains of B. bassiana in agricultural fields and whether this can result in recombinants with altered virulence and host range. In this study we evaluated the likelihood of genetic recombination by determining 1) vegetative compatibility groups (VCG) among B. bassiana strains indigenous to the US and strains that have been mass released for insect control and 2) the frequency of recombination between co-infecting strains of B. bassiana in an insect host, where recombination is likely to occur in nature. Our data revealed a group of genetically similar strains isolated from Colorado potato beetles belonging to the same VCG. These strains originated from the northeastern part of the US and from Quebec and Ontario, Canada. Co-inoculations of beetle larvae with complementary nit mutants resulted in heterokaryon formation only between strains of the same VCG, suggesting that the self/non-self recognition system of the parasexual process is an effective barrier preventing genetic exchange between dissimilar strains in the field. Further studies are being conducted to determine stability and virulence of recombinants.