Comparative analysis of mitochondrial genomes in lycoperdaceae fungi reveals intron dynamics and phylogenetic relationships.

BACKGROUND

The fungi of the Lycoperdaceae family are characterized by their nearly spherical fruiting bodies and possess pharmacological, economic, and ecological values. As a group of highly valuable fungi, the classification of species within the Lycoperdaceae family continues to be a subject of debate. Mitochondrial genomes typically harbor considerable number of genes and genetic elements that offer a wealth of genetic information, making them widely utilized in phylogenetic studies of eukaryotes. However, mitochondrial genome data for the Lycoperdaceae family is insufficient, and investigating its structure offers valuable insights into the evolutionary relationships between puffball fungi and other Agaricales taxa.

RESULTS

In this study, we sequenced and compared the complete mitogenomes of four species of Lycoperdon and Calvatia for the first time. Comparative analysis indicated that introns and open reading frames (ORFs) influence mitochondrial genome size variation among the four species. The gene lengths and nucleotide compositions varied across the species, and synteny analysis suggested potential gene loss during Lycoperdaceae evolution. Phylogenetic relationships of 50 Agaricales and 16 Boletales species were reconstructed based on a concatenated mitochondrial gene dataset. The results elucidated the taxonomic placements of four Lycoperdaceae species within the Agaricales, confirming the monophyly of Lycoperdaceae and its nested position within Agaricaceae. With the expansion of the phylogenetic tree, the number of introns gradually decreased across the Boletales. Additionally, significant inversion and translocation events were observed in the tRNA genes of Lycoperdon pratense.

CONCLUSION

This study represents the first assembly of complete mitogenomes for four species within the Lycoperdaceae family, laying the foundation for subsequent phylogenetic research based on fungal mitochondrial gene dataset. Comparative analysis revealed the contribution of gene composition and introns to the mitochondrial genome size. Their mitochondrial genomes underwent frequent intron loss or gain events and potential intron transfer in evolution.