SMRT Sequencing Revealed Mitogenome Characteristics and Mitogenome-Wide DNA Modification Pattern in .

Single molecule, real-time (SMRT) sequencing was used to characterize mitochondrial (mt) genome of and to analyze the mt genome-wide pattern of epigenetic DNA modification. The complete mt genome of , with a size of 157,539 bp, is the fourth largest Ascomycota mt genome sequenced to date. It contained 14 conserved protein-coding genes (PCGs), 1 intronic protein , 27 tRNAs and 2 rRNA subunits, which are common characteristics of the known mt genomes in Hypocreales. A phylogenetic tree inferred from 14 PCGs in Pezizomycotina fungi supports as most closely related to in Ophiocordycipitaceae. A total of 36 sequence sites in were under positive selection, with dN/dS >1 in the 20 compared fungi. Among them, 16 sites were statistically significant. In addition, the mt genome-wide base modification pattern of was determined in this study, especially DNA methylation. The methylations were located in coding and uncoding regions of mt PCGs in , and might be closely related to the expression of PCGs or the binding affinity of transcription factor A to mtDNA. Consequently, these methylations may affect the enzymatic activity of oxidative phosphorylation and then the mt respiratory rate; or they may influence mt biogenesis. Therefore, methylations in the mitogenome of might be a genetic feature to adapt to the cold and low PO environment at high altitude, where is endemic. This is the first report on epigenetic modifications in a fungal mt genome.