Comparative Mitogenome Analysis Reveals Mitochondrial Genome Differentiation in Ectomycorrhizal and Asymbiotic Amanita Species

Abstract

In this present study, we assembled and analyzed the mitogenomes of two asymbiotic and six ectomycorrhizal <i>Amanita</i> species based on next-generation sequencing data. The size of the eight <i>Amanita</i> mitogenomes ranged from 37,341 to 137,428 bp, and we considered introns to be one of the main factors contributing to the size variation of <i>Amanita</i>. The introns of the <i>cox1</i> gene experienced frequent gain/loss events in <i>Amanita</i>; and the intron position class cox1P386 was lost in the six ectomycorrhizal <i>Amanita</i> species. In addition, ectomycorrhizal <i>Amanita</i> species had more repetitive sequences and fewer intergenic sequences than asymbiotic <i>Amanita</i> species in their mitogenomes. Large-scale gene rearrangements were detected in the <i>Amanita</i> species we tested, including gene displacements and inversions. On the basis of the combined mitochondrial gene set, we reconstructed the phylogenetic relationships of 66 <i>Basidiomycetes</i>. The six ectomycorrhizal <i>Amanita</i> species were of single origin, and the two saprophytic <i>Amanita</i> species formed two distinct clades. This study is the first to elucidate the functions of the mitogenome in the evolution and ecological adaptation of <i>Amanita</i> species.