No jacket required – new fungal lineage defies dress code

Abstract

Analyses of environmental DNAs have provided tantalizing evidence for “rozellida” or “cryptomycota”, a clade of mostly undescribed and deeply diverging aquatic fungi. Here, we put cryptomycota into perspective through consideration of Rozella, the only clade member growing in culture. This is timely on account of the publication in Nature of the first images of uncultured cryptomycota from environmental filtrates, where molecular probes revealed non‐motile cyst‐like structures and motile spores, all lacking typical fungal chitinous cell walls. Current studies of Rozella can complement these fragmentary observations from environmental samples. Rozella has a fungal‐specific chitin synthase and its resting sporangia have walls that appear to contain chitin. Cryptomycota, including Rozella, lack a cell wall when absorbing food but like some other fungi, they may have lost their “dinner jacket” through convergence. Rather than evolutionary intermediates, the cryptomycota may be strange, divergent fungi that evolved from an ancestor with a nearly complete suite of classical fungal‐specific characters.

Ultrastructure of cyst-like fungal bodies in myxomycete fruiting bodies

“…eDNA clones of cryptomycota are common in freshwater, soil and marine microbial communities (James & Berbee 2011, Gleason et al 2012. However, there is no record of the Cryptomycota in the cryosphere (where the biosphere is constantly or seasonally covered with snow and/ or ice).…”

High-level classification of the Fungi and a tool for evolutionary ecological analyses

“…Berbee et al (2017) proposed to include Nucleariida and Fonticulida within the extended kingdom Fungi. This is not, however, warranted in our opinion, because these taxa have never been considered as Fungi and the constituent taxa have several unique structural (lack of chitin cell walls, discoid mitochondrial cristae) and ecophysiological (amoeboid habit, phagocytotic nutrition) characters as well as specific features in genomic structure such as the lack of division II Chitin synthase gene (James and Berbee 2012;Torruella et al 2015). Because Nuclearia spp.…”

“…Because of the historical taxonomic 'heritage', classification of Microsporidea needs to follow the International Code of Zoological Nomenclature (see Didier et al 2014). Rozellomycota and other fungal phyla share the division II Chitin synthase gene, which is absent in the Nucleariae (James and Berbee 2012). Furthermore, Rozellomycota and other fungal phyla share the AAA lysine synthesis pathway and predominately osmotrophic nutrition (Corsaro et al 2014).…”

“…Since nothing is known about the morphology of these clades, we consider these tentatively as subkingdom-level groups within Fungi, because of their supported monophyly with Fungi and divergence time of \ 1000 Ma. Many taxonomists place the unicellular Rozellomycota, Microsporidia and Aphelida within Fungi (James et al 2006a;Jones et al 2011a, Adl et al 2012James and Berbee 2012 and further studies on fungal classification), but other authors indicate the monophyly of Aphelida and Rozellomycota in a sister position to all other Fungi (Karpov et al 2013;2014b, 2017bLetcher et al 2013Letcher et al , 2017 and treat this socalled ARM clade as phylum Ophistosporidia (Karpov et al 2014b) or a part of the intentionally paraphyletic phylum Choanozoa, which includes protists at the base of Metazoa (Cavalier-Smith 2013; Ruggiero et al 2015). However, taxonomically more inclusive phylogenies place these groups separately-Rozellomycota and Microsporidia at the basal position of Fungi but Aphelida nested within 'chytrids' and/or zoopagaceous zygomycetes (Lazarus and James 2015;Tedersoo et al , 2018.…”

1 Fungi from PCR to Genomics: The Spreading Revolution in Evolutionary Biology

“…The single posterior flagellum that gives the opisthokonts their name is, however, retained in only a few clades of fungi that disperse in water ( Fig. 1.1, Rozella and allied Rozellomycota¼Cryptomycota [James and Berbee 2012;Jones et al 2011;Lara et al 2010], Chytridiomycota Monoblepharidomycota, and Neocallimastiogomycota [see Powell and Letcher 2014], Blastocladiomycota [see James et al 2014], Olpidium [see Benny et al 2014]). Once the phylogeny is inferred, however, the biologically interesting fun begins-unraveling the evolution of phenotype.…”