Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 25, 2001
Publication Date: September 1, 2001
Citation: CASTRILLO, L.A., VANDENBERG, J.D., WRAIGHT, S.P. STRAIN-SPECIFIC DETECTION OF INTRODUCED BEAUVERIA BASSIANA IN AGRICULTURAL FIELDS BY USING SEQUENCE-CHARACTERIZED AMPLIFIED REGION MARKERS. SOCIETY FOR INVERTEBRATE PATHOLOGY ANNUAL MEETING. 2001. v. 34. p. 77. Technical Abstract: Field studies on the efficacy and persistence of an introduced microbial control agent require detection assays differentiating the non-native strain from indigenous populations. In the case of the entomopathogen Beauveria bassiana, this is critical because this fungus has a wide host range and is ubiquitous in nature. In this study we developed strain-specific molecular markers based on PCR amplification of sequence-characterized amplified regions (SCAR), in combination with dilution plating on semi-selective medium, to detect and estimate B. bassiana strain GHA propagules in the soil. Using RAPD-PCR, unique fragments that distinguished GHA from other strains of B. bassiana and other species of Beauveria were obtained. Three amplicons generated with primers OPA-14, OPA-15, and OPB-9 were cloned and sequenced, and used as bases for designing GHA-specific primer pairs. PCR assays using SCAR primers OPA-14445, OPA-15441, or OPB-9667 against other strains of B. bassiana from different insect hosts from different locations in the US showed negative results. Whereas, assays against B. bassiana isolates from infected insects and from soil samples from a field recently treated with GHA showed amplicons of the same size as the RAPD fragments cloned from GHA genomic DNA. These strain-specific assays are also highly sensitive, capable of detecting 10 - 100 picograms of DNA, and thus could be used to quantify varying levels of B. bassiana GHA in the field.