Variation in the mitochondrial DNA of the potential biological control agent Chondrostereum purpureum

The mitochondrial DNA (mtDNA) of Chondrostereum purpureum (Pers.:Fr.) Pouza r was extracted and purified, and the size ranged from 51.8 to 66.4 kb. One isolate each from British Columbia, Alberta, Finland, the Netherlands, and New Zealand were found to have identical BamHI mtDNA restriction patterns, resulting in a mitochondrial genome of 63.8 kb. An additional isolate from British Columbia and one from Switzerland had different banding patterns, however, resulting in mitochondrial genomes of 66.4 kb and 51.8 kb, respect ively. A sequence-characterized amplified region (SCAR) assay, based on a p olymerase chain reaction, was developed to rapidly screen a larger populati on of 84 isolates from North America, Europe, and New Zealand. Two SCARs, o ne encoding the NADH 4 gene (3 kb) and the second encoding the ATPase VI an d cytochrome b genes (5.1 kb), were digested with 24 restriction enzymes. T here were no polymorphisms in the NADH 4 containing SCAR, while a single po lymorphism was detected by NsiI in the ATPase VI - cytochrome b containing SCAR. Two mitochondrial haplotypes that were distributed throughout the sam ple population were thus identified. The coancestry coefficient (theta) for all subpopulations of the sample population was calculated to be 0.0353. T he level of gene diversity in the mtDNA of C. purpureum suggested that the chance introduction of novel mitochondrial genes following biological contr ol applications of the fungus is relatively low.