Fruiting body of Saccosoma farinaceum, collection Spirin 13934 (H), origin of the genome. [Photo by Viacheslav Spirin]

In the "1KFG: Deep Sequencing of Ecologically-relevant Dikarya" project (CSP1974), we are sequencing keystone lineages of plant-interacting fungi and saprophytic fungi that are of special ecological importance for understanding terrestrial ecosystems. In addition, comparative genome analysis with saprotrophic, mycorrhizal and pathogenic fungi will provide new insights into the specific and conserved adaptations associated with each fungal lifestyle.

Saccosoma farinaceum IVC104

Saccosoma farinaceum belongs to the class Atractiellomycetes, Pucciniomycotina. This basidiomycete species inhabits decaying wood of both conifers and deciduous trees in the north temperate zone and forms effused, corticioid fruiting bodies that can easily be mixed up with corticioid representatives of Agaricomycetes. Microscopic examination shows that this species has multi-celled, transversally septate basidia, which are characteristic for Pucciniomycotina. Closest relatives of Saccosoma are Phleogena and Bourdotigloea, also in Atractiellomycetes. Together they represent a rare group of wood-inhabiting Pucciniomycotina, most of which are parasitic or free-living yeasts.

Saccosoma farinaceum is very likely a saprotroph, though its ability to decay wood effectively is unknown. Wood decay ability of Pucciniomycotina has not been studied, so this genome will be highly interesting in studying evolution and modes of wood decomposition in basidiomycetes. If species of Atractiellomycetes do turn out to be able to degrade hemicellulose, cellulose or lignin, the main constituents of wood, they would have developed this ability independently from Agaricomycotina, where other wood-decaying basidiomycetes belong to.

Saccosoma farinaceum is the third genome of Atractiellomycetes produced, and it will also be useful in constructing tree of life of Pucciniomycotina and Atractiellomycetes. The genome was produced from a polysporic culture IVC 104, produced from a fruiting body collected in Slovenia from a dry, standing stem of Alnus viridis (=Alnus alnobetula ssp. viridis) (collection Viacheslav Spirin 13934). It belongs thus to Saccosoma farinaceum f. alniviridis, which may represent a separate species from Saccosoma farinaceum sensu typi.

Researchers who wish to publish analyses using data from unpublished CSP genomes are respectfully required to contact the PI and JGI to avoid potential conflicts on data use and coordinate other publications with the CSP master paper(s).