Genomic Characterization of the Endangered Medicinal Polypore Agarikon (Laricifomes officinalis syn. Fomitopsis officinalis)

Agarikon (Laricifomes officinalis syn. Fomitopsis officinalis) is an endangered fungus belonging to a unique lineage in the Polyporales (Basidiomycota) with a growing body of evidence supporting its medicinal value. In this study, we report the hybrid de novo assembly and annotation of the first L. officinalis nuclear and mitochondrial genome sequences, with a nuclear genome size of 28.76 Mb assembled across 66 scaffolds (51.96% GC content; BUSCO completeness of 99.4%), and a complete core mitochondrial genome size of 197.67 kb. Structural and functional annotation of the nuclear genome yielded 8,717 predicted genes including 8,604 protein-coding genes, with 310 genes in 27 biosynthetic gene clusters. We characterized the mating type loci matA and matB, consistent with a tetrapolar mating system, and identified genes encoding key enzymes involved in triterpenoid and polyketide biosynthetic pathways that lead to the production of a diverse array of secondary metabolites. Additionally, we conducted maximum likelihood phylogenomic analysis to confirm the taxonomic position of L. officinalis among 21 species in Polyporales using protein sequences for 860 shared BUSCO genes. This high-quality annotated genome of L. officinalis will serve as a foundation for further investigations into the evolutionary history of this distinct fungal lineage, provide a reference for future population genomic analyses, and elucidate mechanisms underlying the synthesis of the bioactive compounds responsible for agarikons wide-ranging medicinal benefits.