Rapid Discrimination of Mitochondrial DNA Type and Use of Results to Study Mitochondrial Inheritance in Pleurotus spp

We have reported a simple and rapid method to discriminate species in the genus Pleurotus by analysis of restriction-fragment-length polymorphism of whole-cell DNA, and found that several restriction enzymes gave DNA bands useful in such discrimination, but other enzymes tested did not. In the present study, we report the reason why there were useful and useless enzymes; the effective enzymes digested rDNA into small fragments that did not interfere with the detection of DNA bands useful for discrimination. The origin of these discriminative DNA bands was found to be mitochondrial DNA when the banding profiles of whole-cell DNA, mitochondrial DNA, and nuclear DNA were compared. Consequently, our method could be used for rapid and simple identification of mitochondrial DNA type in the genus Pleurotus. The results were used to study mitochondrial inheritance, and we found that only the nucleus but not the mitochondria migrated during the mating of Pleurotus cornucopiae with P. citrinopileatus.