Fruiting body of Skeletocutis stellae growing on a rotten trunk of Picea abies, Finland (Miettinen 21578). This collection is the origin of the genome strain. [Photo credit: Otto Miettinen]

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.

Skeletocutis stellae

Skeletocutis stellae is a well-known polypore in Europe, where it is found on national red lists of many countries and is used as an indicator species in forest surveys in North Europe (Nitare 2000; Niemelä 2016). It is a boreal species found in mountains in the temperate zone, from Croatia and Corsica in the south to the Arctic circle in the north. Skeletocutis stellae grows on big, fallen logs of Pinaceae, and causes white-rot. The perennial fruiting bodies typically appear late in decay succession, when the trunk is already quite rotten. A typical growth place is a well-stocked, coniferous old-growth forest. The species is reportedly wide-spread in North America with a similar ecology (Gilbertson and Ryvarden 1987), but being a species complex, these records may belong to sister species of S. stellae sensu typi. At least part of the records from boreal to temperate East Asia belong to this species, so it has a wide distribution in Eurasia (Dai and Penttilä 2006; Dai 2010).

Skeletocutis stellae is the type species of the genus Incrustoporia, which in turn is the basis of the family Incrustoporiaceae. In their revision of the Polyporales (Agaricomycetes, Basidiomycota), Justo et al. (2017) accepted Incrustoporiaceae as a good family. Their analysis suggested this family of white-rotters might be related to the brown-rotters of the Polyporales, e.g. Fomitopsidaceae and Laetiporaceae. If true, this would make Incrustoporiaceae a very interesting group in understanding the origins of brown rot in the Polyporales through comparative genomics. The genome of S. stellae may also be used in designing genetic markers to monitor viability of its fragmented population.

The DNA extraction used for the genome sequencing was made from a polysporic culture (OMC 1752 / FBCC 2659) that derives from a fruiting body (Miettinen 21578) collected in Kainuu region in central Finland. The host tree was Picea abies in a spruce-dominated old-growth forest.

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).