Home • Ischnoderma benzoinum IVC119 v1.0
Ischnoderma benzoinum fruiting on a stump of spruce in Helsinki, Finland (collection Miettinen 22854). [Photo by Otto Miettinen]
Ischnoderma benzoinum fruiting on a stump of spruce in Helsinki, Finland (collection Miettinen 22854). [Photo by 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.

Ischnoderma benzoinum IVC119

This polypore is wide-spread in the conifer forests of boreal and north temperate Eurasia. It inhabits dead conifer trunks and causes white rot. In Europe, Picea abies is the favorite host. The annual fruiting bodies often emit a pleasant, fruity smell.

Ischnoderma is a small genus, with only two commonly recognized, very similar species. They belong to the Polyporales (Agaricomycetes, Basidiomycota) and represent an isolated lineage within the order, labelled as the family Ischnodermataceae. Phylogenetic analysis of Justo et al. (2017) placed the origin of their lineage at the base of the Polyporales family tree, though with no support. The position of this genus and family is important in understanding evolution in the Polyporales. This order is arguably the single most important group containing both white and brown rot fungi. Describing the genetic basis of wood decomposition systems in various lineages will benefit the evolutionary reconstruction, as well as practical application, of fungal wood decomposition ability.

Although morphologically Ischnoderma are no different from other Polyporales, they do exhibit a rare combination of characters, being white rot fungi with a bipolar mating system (Nobles 1965). Most Polyporales have a tetrapolar mating system, and most species with a bipolar system are brown rot fungi such as Fomitopsidaceae (Ryvarden 1991; Nobles 1971; Nakasone 1990). It is unclear why rot type and mating system seem to correlate - it may be a coincidence that the ancestor of brown rots happened to be bipolar, or there may be other biological processes behind this trend. Ischnoderma is not a unique genus in this sense - for instance Bjerkandera and Phlebia s.s. are also bipolar - but since it represents a basal lineage it could offer an interesting perspective to the evolution of mating systems in the Polyporales.

The genome strain (IVC 119) derives from a hyphal transplant of a fruiting body (leg. Ilya Viner 2020_22), collected in Helsinki, Finland, on Picea abies.

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).

References:

  • Justo A, Miettinen O, Floudas D, Ortiz-Santana B, Sjökvist E, Lindner D, Nakasone K, Niemelä T, Larsson K-H, Ryvarden L, Hibbett DS (2017) A revised family-level classification of the Polyporales (Basidiomycota). Fungal Biol 121 (9):798-824. doi:10.1016/j.funbio.2017.05.010
  • Nakasone KK (1990) Cultural studies and identification of wood-inhabiting Corticiaceaea and selected hymenomycetes from North America. Mycologia Memoir 15:1-412
  • Nobles MK (1965) Identification of cultures of wood-inhabiting Hymenomycetes. Canadian Journal of Botany 43 (9):1097-1139
  • Nobles MK (1971) Cultural characters as a guide to the taxonomy of the Polyporaceae. In:Petersen RH (ed) Evolution in the higher Basidiomycetes. The University of Tennessee Press, Knoxville, pp 169-196
  • Ryvarden L (1991) Genera of polypores. Nomenclature and taxonomy. Synopsis Fungorum 5:1-363