Phylogenetic Relationships of Cordyceps Species Revealed by ITS Sequences of Ribosomal DNA

The internal transcribed spacer (ITS) regions of seven Cordyceps species and two species belonging to the same family of Clavicipitaceae, Phytocordyceps ninchukispora and Claviceps purpurea, were analyzed by polymerase chain reaction amplification and direct DNA sequencing. Phylogenetic relationship trees based on the sequences of ITS-I and ITS-II were constructed. The sequence similarities of the two regions of C. sinensis between the fresh samples collected from Tibet and the dried specimens from Chinese herb stores in Taiwan were 99.5% and 99.7%, respectively. However, the sequences were compared with those of C. sinensis collected from the CCRC (Culture Collection and Research Center). The similarities of ITS-I and ITS-II were only 71.2% and 81.5%, respectively. Equivalent sequencing results were obtained no matter whether the genomic DNA was extracted from the tissues of C sinensis, its stroma, or the host of the fungus.