Comparative analysis of the complete mitochondrial genomes of four cordyceps fungi.

Cordyceps is a large group of entomogenous, medicinally important fungi. In this study, we sequenced, assembled, and annotated the entire mitochondrial genome of , in addition to comparing it against other three complete cordyceps mitogenomes that were previously published. Comparative analysis indicated that the four complete mitogenomes are all composed of circular DNA molecules, although their sizes significantly differ due to high variability in intron and intergenic region sizes in the and . mitogenomes. All mitogenomes contain 14 conserved genes and two ribosomal RNA genes, but varying numbers of tRNA introns. The Ka/Ks ratios for all 14 PCGs and were all less than 1, indicating that these genes have been subject to purifying selection. Phylogenetic analysis was conducted using concatenated amino acid and nucleotide sequences of the 14 PCGs and using two different methods (Maximum Likelihood and Bayesian analysis), revealing highly supported relationships between . and other species, in addition to a close relationship with . . Further, the analyses indicated that and play important roles in population differentiation. These mitogenomes will allow further study of the population genetics, taxonomy, and evolutionary biology of medicinally important cordyceps species.