Fungalpedia – Note 13 Barromyces
Citation: Bhunjun et al. 2023 – Fungalpedia, genera described in 2018, Mycosphere (in press)
Barromyces M.J. Powell & Letcher
Index Fungorum number, Facesoffungi, MycoBank, GenBank, Fig. 1
Barromyces was introduced by Powell et al. (2018) to accommodate B. tenuis D.J.S. Barr (≡ Gaertneriomyces tenuis D.J.S Barr). It is classified under Spizellomycetaceae, Spizellomycetales, Chytridiomycetes, Chytridiomycota (Powell et al. 2018). Chytrids frequently exhibit morphological plasticity, which can be confusing when the strains are cultivated on various media (Powell & Koch 1977). Barr (1980) established Spizellomycetales D.J.S. Barr as a new order to accommodate soil-inhabiting strains of Phlyctochytrium to accommodate taxa with different zoospore structures. Gaertneriomyces was introduced as one of the genera, however, diverse thallus morphological characters of G. tenuis suggested that it might represent a new genus since it shared morphological characteristics with both Gaertneriomyces and Spizellomyces (Barr 1984) Phylogenetic analysis of 16S rRNA, 18S rRNA and ITS sequences also supported the introduction of Barromyces (Powell et al. 2018). Physiology, thallus morphology and zoospore ultrastructure distinguish B. tenuis from Gaertneriomyces (Powell et al. 2018). Barromyces has only one species and it is characterized by unique zoospore ultrastructural characteristics (Powell et al. 2018). Zoospores of B. tenuis are spherical, but can also be elongate, irregular, or amoeboid. The mature thallus of Barromyces has a single main rhizoidal axis that is faintly inflated, as well as a short rhizoidal system. The released zoospores frequently germinate close to the parent sporangium. The zoospore nucleus of B. tenuis is positioned in the rear, with a concavity above the kinetosome (Powell et al. 2018). Barromyces is saprobic in crop soil or dung (Powell et al. 2018).
Type species: Barromyces tenuis (D.J.S Barr) M.J. Powell & Lecther
Basionym: Gaertneriomyces tenuis D.J.S Barr
Fig 1. Barromyces tenuis (BR 366, holotype). a. Germling with slender germ tube. b. Germling with spherical sporangium and slightly swollen germ tube with sparsely branched rhizoids. c, d. Immature thallus with spherical sporangium. e. Sporangium with discharged papillae. f. Thallus with sporangium, an apophysis and open-branched rhizoids that are not greatly extended. g. Zoospore with discharged zoospores germinating near parent sporangium, elongate zoospores. Scale bar: a–d = 10 μm, e–g = 20 μm. Redrawn from Powell et al. (2018).
References
Barr DJS. 1980 – An outline for the reclassification of the Chytridiales, and for a new order, the Spizellomycetales. Canadian Journal of Botany. 58, 2380–2394. http://dx.doi.org/10.1139/b80-276
Barr DJS. 1984 – The classification of Spizellomyces, Gaertneriomyces, Triparticalcar, and Kochiomyces (Spizellomycetales, Chytridiomycetes. Canadian Journal of Botany 1171–1201. https://doi.org/10.1139/B84-161
Powell MJ, Koch WJ. 1977 – Morphological variations in a new species of Entophlyctis. I. The species concept. Canadian Journal of Botany. 55, 1668–1685. http://dx.doi.org/10.1139/b77-195
Powell MJ, Letcher PM, Chen SF. 2018 – Phylogeny and Taxonomic Revision of the Soil Chytrid, Gaertneriomyces, and Description of the New Genus Barromyces (Spizellomycetaceae, Chytridiomycota). Nova Hedwigia. 107, 205–28. https://doi.org/10.1127/nova_hedwigia/2018/0465
Entry by
Anujani Gunarathne, The Center of Excellence in Fungal Research, Mae Fah Luang University, Thailand.
(Edited by Chitrabhanu S. Bhunjun and Kevin D. Hyde)
Published online 8 May 2023