Phylogenetic Relationships of Genera Coprinus and Psathyrella on the Basis of ITS Region Sequences

The internal transcribed spacer regions(ITS) of the ribosomal DNA gene repeat from Coprinus and Psathyrella spp. were amplified using polymerase chain reaction (PCR) and sequenced. Sequences from 11 species including Coprinus comatus, C. atramentarius, C. micaceus, C. cinereus, C. rhizophorus, C. radians, C. echinosporus, C. disseminatus, Psathyrella candolleana, P. spadiceogrisea and Stropharia rugosoannulata were compared. The spacer region I and II were in length respectively and partially contained 17S, 5.8S and 25S. The reciprocal homologies of ITS sequences among these strains were in the range of . According to the analysis of ITS sequences, Coprinus and Psathyrella spp. were classified into three clusters. Cluster I consisted of Coprinus lagopus, C. cinereus, C. echinosporus, C. rhizophorus, and C. atramentarius. Cluster II comprised C. micaceus, C. radians, C. disseminatus, Psathyrella candolleana, and P. spadiceogrisea. On the other hand C. comatus is in Cluster III with Stropharia rugosoannulata even though this species is belonging to the section Coprinus in morphological aspect. These results suggest that taxonomic position of Psathyrella would better be inculded in genus Coprinus. Coprinus comatus, the type species of Coprinus, gives a doubt on monophyletic evolution and is assumed to be paraphyletic or polyphyletic.