Genetic structure of the foliar pathogen Dothistroma septosporum in northwest British Columbia suggests recombination and high gene flow.

Genetic structure and reproductive mode was studied in the pine pathogen Dothistroma septosporum using amplified fragment length polymorphism (AFLP) and mating type markers in 19 populations in northwest BC. Within population diversity was high as determined by AMOVA (85%, p = 0.000). Twelve of 19 populations were not significantly different from each other suggesting high gene flow. The remaining seven populations showed some level of divergence possibly due to historic separation. Genotypic diversity was high, and overall mating type segregation did not differ significantly from 1:1 suggesting the presence of sexual reproduction. However, statistical mating tests suggest that only a few populations are randomly mating. Growth rate and toxin production was highly variable between isolates, and overall toxin production was relatively low and did not differ significantly between two populations. Results indicate a high evolutionary potential and long distance dispersal in this pathogen, important to consider in future forest management.