Mitochondrial DNA in Mon‐Mon and Di‐Mon Pairings of Pleurotus ostreatus

Abstract:Based on enzymatically amplified regions of the mitochondrial DNA (mtDNA), stock‐specific markers were obtained for two stocks of Pleurotus ostreatus. A length mutation was detected within a region encoding for DNA of the mitochondrial ribosomes. The inheritance of mtDNA was uniparental both in Mon‐Mon and Di‐Mon interstock pairings. Replacement of the recipient mtDNA to a large extent was finished 3 to 4 months after hyphal contact of paired mycelia. Dissolution of mitochondrial mosaics was somewhat faster in Di‐Mon than in Mon‐Mon pairings. As became evident in Di‐Mon pairings, the spread of the dominating mtDNA is independent from nuclear migration, and these processes could go in opposite directions. While in compatible Di‐Mon pairings two different types of nuclear background develop with respect to the mating type factors, only one certain mtDNA phenotype remained after dissolution of the mitochondrial mosaic. The spread of the mtDNA occurred at a distinctly slower rate than nuclear migration. Three weeks after hyphal contact the dominating mtDNA had not reached the growing edge of the recipient mycelium, whereas clamp formation was noted after 11 days at the latest. The data presented in this study indicate that no apparent correlation exists between mtDNA and nuclear background.