Comparison of RAPD technique and somatic incompatibility tests for the identification of Phlebiopsis gigantea strains

Somatic incompatibility assays and random amplified polymorphic DNA (RAPD) analysis were assessed and compared for use in monitoring the survival of introduced strains of Phlebiopsis gigantea, a fungal biocontrol agent used against Heterobasidion annosum root rot. Overall there was concordance between the two methods. All incompatible strains exhibited different RAPD profiles whilst compatible ones, with two exceptions, had the same RAPD profile. Somatic incompatibility tests and RAPD profiles generated by three primers, from which 11 markers were retained, could distinguish field-tested strains from among 60 strains from a population collected in Quebec and Ontario. Furthermore, both methods allowed us to clearly demonstrate the presence of inoculated strains 1 year after treatment. The combined use of these techniques provides a valuable tool for discriminating between different P. gigantea strains and conducting epidemiological studies.