Mitochondrial DNA inheritance in sexual crosses of Pleurotus ostreatus

The inheritance of mitochondrial DNA (mtDNA) in sexual crosses was investigated to expand our understanding of the large genetic divergence in mtDNAs among natural populations of the higher basidiomycete Pleurotus ostreatus. Reciprocal crosses were made between compatible monokaryons with distinguishable mtDNA restriction fragment length polymorphisms (PFLPs). Almost all of the dikaryons produced by these crosses had mtDNA genotypes from one of the parental monokaryons. However, for dikaryons isolated from the junction-zone of crossed monokaryons, recombinant mitochondrial genomes commonly appeared. These results showed that P. ostreatus mtDNA can be inherited biparentally, via mtDNA recombination, as well as uniparentally. Further, it was suggested that mtDNA recombination may be an important source of variation in mitochondrial genomes among natural populations of P. ostreatus.