Mitochondrial Genomes in Symbiotic Organisms: Lineage Specific Variation Across the Mitochondrial Genomes of Lichen Forming Fungi

Many fungi are involved in iconic mutualistic symbiotic associations, including mycorrhizas, lichens, fungus-growing ants, among many others. While mutualistic fungi play important ecological and evolutionary roles, a number of major evolutionary questions have not yet been adequately addressed, including the dynamics of mitochondrial genome evolution. Ecologically and evolutionarily important lichen-forming fungal lineages have received very little attention in terms of mitochondrial genome evolution, and general patterns in genome evolution are largely unknown. To provide novel insights into the mitochondrial genome evolution in the most diverse order of lichen-forming fungi, Lecanorales, we de novo high-throughput sequenced the mitochondrial genomes of over 30 individual of the genus Rhizoplaca, the rimmed navel lichens. Our comparative genomic approach shows structural variability due to active recombination, lineage specific intron patterns, and high sequence diversity across the genus. Utilizing this genome information will allow us to understand long standing questions about the mitochondrial genome evolution of closely obligate symbiotic organisms.