Determination of the mating system of Grifola frondosa (maitake) IM-BM21

Abstract

In this study, we crossed 31 basidiospore isolates from the fruit bodies of dikaryotic strain <i>Grifola frondosa </i> IM-BM21 to analyze mating compatibility groupings. Two incompatibility groups ( <i>A1 </i> and <i>A2 </i>) were identified, identifying <i>G. frondosa </i> as a bipolar mushroom. Based on nucleotide sequences of whole genomic DNA of <i>G. frondosa </i> WM1-25 from next-generation sequencing, we designed oligonucleotide primers to amplify the homeodomain protein gene located on the <i>A </i> locus ( <i>A1hox2 </i>) and pheromone genes ( <i>A1phb1 </i>) located on the <i>B </i> locus in the tetrapolar mushroom. The DNA fragment of the <i>A1hox2 </i> gene was amplified only from <i>A1 </i> monokaryotic strains and the <i>A1phb1 </i> gene was amplified in all <i>A1 </i> and <i>A2 </i> monokaryotic strains. Therefore, the linkage groups of the analyzed genes were defined as <i>A1hox2 </i> in linkage group I, which is closely linked to <i>A </i> mating-type locus, and <i>A1phb1 <i>, which has no relationship with mating type.