Physical mapping of the mitochondrial genome of the cultivated mushroom Agaricus brunnescens (= A. bisporus)

Summary Mitochondrial (mt) DNA from the commercial mushroom Agaricus brunnescens Peck = A. bisporus (Lange) Imbach] was purified by cesium chloride/bisbenzimide gradient centrifugation. A physical map of the mtDNA fragments produced by BamHI, EcoRl, and PvuII digestion was generated by filter hybridizations with radiolabelled BamHI mtDNA probes. The A. brunnescens mtDNA was a circular molecule 136 kilo-basepairs (kbp) in length and contained an inverted repeat between 4.6 and 9.2 kbp in size. Orientational isomers of the mitochondrial genome were not detected. The positions of six genes were located on the A. brunnescens mtDNA map by heterologous hybridization. No coding function has yet been ascribed to the inverted repeat. The large rRNA gene was located on the smaller single copy region. The genes for cytochrome b, cytochrome oxidase (subunit III), ATPase (subunits 8 and 6) and the small rRNA were located on different regions of the larger single copy region.