Use of DNA heteroduplex analysis to distinguish the Seiridium isolates causing cypress canker in the mediterranean region.
A novel assay was employed to differentiate the cypress canker pathogens Seiridium cardinale and S. cupressi. The approach was based on polymerase chain reaction (PCR)-amplification of the internal transcribed spacer 2 region of the ribosomal DNA. Aliquots of the amplification products of each isolate were combined in pairs and subjected to electrophoretic migration as double strands in DNA heteroduplex polymorphism analysis (HPA). S. cardinale was distinguished from S. cupressi through the conformation of the double helix structure and its perturbation by base mispairings in the heteroduplex molecules. The combination of PCR with HPA allowed the rapid screening of Seiridium isolates to differentiate between the isolates.