Abstract
To investigate the geographical origin of Grifola frondosa (maitake) strains, we amplified the DNA region between exons 2 and 3 of mitochondrial cox1 in strains from Japan and China. The amplified fragments were approximately 3,000 bp in three Chinese strains, approximately 1,800 bp in nine Japanese strains, and approximately 200 bp in three other Japanese strains. Sequence analysis revealed that a unique intron C, encoding a GIY-YIG nuclease gene, was present only in the Chinese isolates. The LAGLIDADG nuclease gene was identified in the 1,800 bp amplicons from both Chinese and Japanese isolates. The intron was absent in the 200 bp amplicons. Comparative analysis of the non-coding region of intron 2 showed that 10 of the 14 strains could be distinguished based on nucleotide sequence, suggesting its potential as a marker for determining geographic origin. No correlation was observed between mitochondrial DNA genotype and the presence of a barrage reaction or colored border line.
