The 287,403 bp Mitochondrial Genome of Ectomycorrhizal Fungus Reveals Intron Expansion, tRNA Loss, and Gene Rearrangement.

In the present study, the mitogenome of was assembled and analyzed. The mitogenome of comprises 15 conserved protein-coding genes, two rRNA genes, and 14 tRNAs, with a total size of 287,403 bp. Fifty-eight introns with 170 intronic open reading frames were detected in the mitogenome. The intronic region occupied 69.41% of the mitogenome, which contributed to the mitogenome significantly expand relative to most fungal species. Comparative mitogenomic analysis revealed large-scale gene rearrangements occurred in the mitogenome of , involving gene relocations and position exchanges. The mitogenome of was found to have lost several tRNA genes encoding for cysteine, aspartate, histidine, etc. In addition, a pair of fragments with a total length of 32.91 kb in both the nuclear and mitochondrial genomes of was detected, indicating possible gene transfer events. A total of 12.83% intragenomic duplications were detected in the mitogenome. Phylogenetic analysis based on mitochondrial gene datasets obtained well-supported tree topologies, indicating that mitochondrial genes could be reliable molecular markers for phylogenetic analyses of Ascomycota. This study served as the first report on mitogenome in the family Tuberaceae, thereby laying the groundwork for our understanding of the evolution, phylogeny, and population genetics of these important ectomycorrhizal fungi.