Characterization of the five Amanita complete mitochondrial genome and the phylogenetic relationship with other Amanita fungi.

Background: Amanita is a large genus of mushrooms with a rich biodiversity. It includes the world's most poisonous mushroom, which is responsible for 90% of mushroom-related fatalities. However, it is difficult to distinguish lethal and edible Amanita species because of their morphological similarities.

Results: To identify molecular data and explore the phylogenetic relationships within Amanita, we sequenced and analyzed the mitochondrial genome (mitogenome) of five Amanita species and compared them with nine previously published Amanita mitogenomes. We analyzed the genomic structures, tandem repeats and gene rearrangements, introns, adenine-thymine (AT) skew, guanine-cytosine (GC) skew, and transfer RNAs (tRNAs) of the five Amanita species. Phylogenetic trees were constructed among 55 species from Agaricomycetes, including 14 species of Amanita, 39 species of Agaricales, and two outgroup species of Auriculariales, based on two different datasets (15 protein-encoding genes [PCGs] of amino acids and 15 PCGs of codons). Phylogenetic analysis revealed that the 14 Amanita species had consistent phylogenetic positions with the current phylogeny. Amanita was divided into three subgenera (subgenus Amanita, subgenus Amanitina, subgenus Lepidella). Moreover, the phylogenetic analysis confirmed that ectomycorrhizal and asymbiotic species clustered into different subgenera.

Conclusions: We described the features of Amanita mitogenome, including the genomic structures, tandem repeats and the rearrangement of the PCGs related to classification status, which showed a different arrangement of genes and clear rearrangement with the introns between the ectomycorrhizal and asymbiotic. Finally, we proposed that the subordinate taxon of Amanita requires further revision. This study provides insights into the evolution and structural characteristics of the mitogenomes of macrofungal organisms.