DNA amplification fingerprinting provides evidence that Discula destructiva, the cause of dogwood anthracnose in North America, is an introduced pathogen

Abstract

DNA amplification fingerprinting was used to characterize 28 isolates of Discula destructiva and three isolates of an undescribed species of Discula. These filamentous fungi cause anthracnose of various species of dogwood (Cornus). Isolates were obtained from throughout the disease range in the eastern and western United States and western Canada and DNA amplification fingerprinting profiles generated with 10 arbitrary oligonucleotide primers. Fifty-nine of 302 loci examined were polymorphic between isolates of D. destructiva, whereas a greater number were observed between and among the isolates of Discula species. Relationships among and between the two fungal groups were ascertained using cluster analysis and phylogenetic analysis using parsimony. DNA profiles resulting from pooled (equal amounts) DNA from five isolates of D. destructiva from the eastern United States were compared to profiles from bulked DNA from five and 10 isolates from western United States to discern differences between the two geographical populations. The genome of D. destructiva appears to be highly conserved throughout the range of the disease, whereas isolates of Discula species exhibited greater variability. Profiles of bulked DNA from eastern and western United States were identical indicating very few differences between the populations. The data suggest that D. destructiva was recently introduced into North America.

Key Words:

• arbitrary primers
• Cornus species
• DAF
• Discula destructiva
• genomic analysis