Sistotrema muscicola fruiting body growing on brown-rot pine wood in Suomussalmi, Central Finland (collection Otto Miettinen 20319, origin of the genome strain). [Photo credit: Otto Miettinen]

In the “1KFG: Deep Sequencing of Ecologically-relevant Dikarya” project (CSP1974), we aim to sequence additional sampling of genomic diversity within 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.

Sistotrema muscicola

Sistotrema muscicola is a species complex of soil-inhabiting corticioid fungi. Species of this complex have been shown to be ectomycorrhizal (Nilsson et al. 2006). They are found throughout temperate forests (Eriksson et al. 1984, Ginns and Lefebvre 1993), and reported from Africa (Hjortstam and Larsson 1994).

Their fragile, small fruiting bodies develop on the underside of rocks, wood remnants or dead leaves. Underside of the fruiting body ranges from spines to pores and everything in between, yet under microscope the species are quite similar. As of 2020 there was no revision of this species group available, and the identity of S. muscicola sensu typi described from Central Europe remains obscure. The genome strain was cultured in Northern Finland in a dry old-growth pine forest, where it grew under a log. The hymenophore of this species is hydnoid to irpicoid, and it forms very likely mycorrhiza with Pinus sylvestris (the only other, unlikely option really being small Ericaceae bushes). It is possible that the species also retains some wood decomposition ability, degrading wood remnants in the soil.

Sistotrema muscicola is a member of the early-diverging order Cantharellales (Agaricomycetes, Basidiomycota), and appears to be related to Hydnum and other mycorrhizal species within the order. The genome will help to establish a robust classification system for this order and shed light on the phylogenetic diversity of the polyphyletic genus Sistotrema. It will also prove useful in evolutionary studies of the mycorrhizal habit and early modes of wood decay.

Researchers who wish to publish analyses using data from unpublished CSP genomes are respectfully required to contact the PI and JGI to avoid potential conflicts on data use and coordinate other publications with the CSP master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