Tag Archives: taxonomy

One Fungus, One Name

The naming of organisms is an important part of how we communicate. When a fungus is found, be it a mycelium from a rotting fruit, a mushroom from the forest, or something growing on a petri dish, we have used morphological and other phenotypic characteristics to group them together and identify if it is an already known species or a new one. However, some fungi have very different shapes and forms that occur during asexual and sexual (after mating with a partner) stages, some incredible elaborate and even (to some people) beautiful. Because these stages mean that fungi can look very different, and often these fungi are not amenable to life in the laboratory (e.g. we can’t get it to complete the lifecycle in an petri dish in the lab), it was the case that observed asexual (or anamorphic) and sexual (teleomorphic) forms of a species get different names. For some species, connecting the two forms has eluded mycologists, and those which had a lack of a sexual stage were called Fungi Imperfecti. Some fungi are only thought to have an asexual stage, though that may change as more molecular and other data is developed.

If we don’t share names that refer to the same thing, how do I know the mushroom you found in Alaska is the same as the one from North Carolina? ¬†Enter molecular identification of species by genotyping a common marker sequence such as the ITS spacer region of Fungi. The ITS region (Intergenic Internal Transcribed Spacer) has been proposed as the best molecule for this based on a variety of analyses and has been deployed in labs for many years. Other marker sequences (such as intron and COX1/COI) have been proposed but so far it appears that ITS is the blessed marker for fungi by the Barcode of Life project for the time being (see the fungal barcoding site too). The recent Amsterdam declaration proposed we could name fungi with a single name based on this marker sequence and perhaps simplify life for new students learning to memorize two names for a fungus which has a sexual and asexual lifecycle.

A summary of the history and challenges here can be found in a recent paper in IMA Fungus by John Taylor One Fungus = One Name: DNA and fungal nomenclature twenty years after PCR (available pre-print here). In particular we can see that at least two papers have gone ahead and taken the Amsterdam proposal to heart and had already starting named one name for groups of fungi (perhaps predating the proposal) and removing what may seem confusing and perhaps outdated approach of teleomorph and anamorph naming. See Houbraken et al and also Crous et al where the authors state “Separate teleomorph and anamorph names are not provided for newly introduced genera, even where both morphs are known”.

Many mycologists are looking on as to what will happen next as to the naming of future species and how we unify this. We also hope to have better approaches to naming Environmental sequences which are only known by the sequence of ITS obtained from a soil, water, air, plant material sequencing experiment. A discussion held at the MSA meeting in Fairbanks will produce a more mature position paper lead by David Hibbett that can be discussed and vetted by the community as to how to proceed with deluge of new unidentified species that will emerge from large scale pyrosequencing of environments. If you have ideas, concerns, or want to read and comment on the current ideas in the proposal, please contact David. Hopefully we can surf this wave and get new names in the system lest we be swept away by it!

John W Taylor (2011). One Fungus = One Name: DNA and fungal nomenclature twenty years after PCR IMA Fungus, 2 (2) : 10.5598/imafungus.2011.02.02.01

Houbraken, J., Frisvad, J., & Samson, R. (2010). Taxonomy of Penicillium citrinum and related species Fungal Diversity, 44 (1), 117-133 DOI: 10.1007/s13225-010-0047-z

New species of Cryptococcus found in seawater

A paper in IJSEM describes a new species in the Cryptococcus basidiomycete yeast lineage. The name is proposed as Cryptococcus keelungensis sp. nov. for a strain isolated from the sea surface microlayer. Its identity as a Cryptococcus sp was determined by sequencing of 26S rDNA D1/D2 and ITS loci and molecular phylogenetics. This is quite diverged from the human pathogen Cryptococcus neoformans and C. gattii as the new species falls in the order Filobasidiales while C. neoformans is classified in the order Tremellales. Interestingly, based on the phylogeny in the paper it seems to be relatively close to newly discovered Cryptococcus himalayensis.

See also:

C.-F. Chang, C.-F. Lee, S.-M. Liu (2008). Cryptococcus keelungensis sp. nov., an anamorphic basidiomycetous yeast isolated from the sea-surface microlayer of the north-east coast of Taiwan INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 58 (12), 2973-2976 DOI: 10.1099/ijs.0.65773-0