Environmental sequencing regularly recovers fungi that cannot be classified to any meaningful taxonomic level beyond “Fungi”. There are several examples where evidence of such lineages has been sitting in public sequence databases for up to ten years before receiving scientific attention and formal recognition.
No doubt, there are many not yet described fungi, and public DNA databases contain thousands of fungal sequences that cannot be assigned to any known fungal group with confidence. Very often these fungi can't be cultured in order to establish some taxonomic baseline. As a result many of these sequences have defied robust taxonomic assignment for more than 10 years. Some 100,000 species of fungi have been described formally, although current estimates put the number of extant fungal species to at least 6 million. The vast dark fungal diversity unraveled by molecular techniques hints that the interaction between fungal taxonomy and DNA sequencing of environmental substrates such as soil and water is not necessarily optimal.
There is no taxonomic feedback loop in place to highlight the presence of these enigmatic lineages to the mycological community, and they often end up in sequence databases for years without attracting significant research interest.
Frustrated about this situation, an international group of researchers took the matter into their hands and now presents a search function in the UNITE database for molecular identification of fungi. Its aim is to highlight the fungi we know the least about, and invite the scientific community to resolve their taxonomic affiliation. The effort seeks to bridge the substantial knowledge gap between fungal taxonomy and molecular ecology through a list, the authors refer to as the "50 Most Wanted Fungi." The list is recomputed on a monthly basis, accounting for any updates and additions contributed by the scientific community between each iteration. Community participation is strongly encouraged, and the UNITE database has extensive support for third-party annotation.
By highlighting these fungal lineages, the colleagues hope to speed up the study and formal description of these species.
Indeed, nothing can be said of the way they make a living. It is simply not known. We make no claim as to the importance of these fungi from whatever point of view -- ecological, economic, or otherwise. We do make claim to their uniqueness, though, because it is frustrating, in the year 2016, not to be able to assign a name to a fungal sequence even at the phylum level.