Exophiala Frigidotolerans Fungal Planet Description Sheets 391

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Exophiala frigidotolerans Fungal Planet description sheets 391

Fungal Planet 1079 – 29 June 2020

Exophiala frigidotolerans Rodr.-Andr., Cano & Stchigel, sp. nov.

Etymology. From Latin frigus-, cold, and - tolerans, tolerant, referring to melanised cell walls. The genus Exophiala is characterised by its ability to grow fast at lower temperatures than 20 °C. an annellidic conidiogenesis and the production of solitary co- Classiﬁcation — Herpotrichiellaceae, Chaetothyriales, Chae nidia grouping in slimy masses, and its phylogenetic afﬁliation tothyriomycetidae, Eurotiomycetes. to the ascomycete order Chaetothyriales (De Hoog et al. 2011). This genus contains numerous potential opportunists or patho- Mycelium composed of pale olivaceous brown, septate, branch- gens of immunocompetent humans (Sudhadham et al. 2008, ed, smooth- and thin-walled hyphae, 1–3 μm wide; older hy- Li et al. 2008, 2009) and are isolated from a broad spectrum phae being more strongly pigmented. Spirally twisted hyphae of substrata, environments and geographic areas (De Hoog present. Moniliform cells scarce, globose to ellipsoidal, in short et al. 2011, Ferrari et al. 2011). As in E. psychrophila, E. frigi- chains (–5 cells). Conidiophores semi-micronematous, pale dotolerans exhibited the ability to grow at low temperatures. olivaceous brown, smooth- and thin-walled, mostly laterally However, E. frigidotolerans presents more developed conidio disposed on the vegetative hyphae, sometimes terminally dis- phores than E. psychrophila (which are reduced to a unique posed, erect, rarely once branched near the base, cylindrical, discrete conidiogenous cell in this latter species), and produces with a rounded or pointed apex, 0–4-septate, with a terminal shorter chains of moniliform cells (scarce and of up to 5 cells conidiogenous locus, sometimes with additional conidiogenous in the former species, and very abundant and of up to several loci, 8–85 × 2–4 μm. Conidiogenous cells enteroblastic, mono- hundred of cells in the latter). or polyblastic, integrated to the conidiophores, on vegetative Based on a megablast search of NCBIs GenBank nucleotide hyphae or well-developed, in the latter case ellipsoidal, ovoid database, the closest hit using the ITS sequence is the ex-type or flask-shaped, 5–11 × 2–3 μm, conidiogenous loci cylindri- strain of Exophiala brunnea CBS 587.66 (GenBank JF747062; cal or conic-cylindrical, with small percurrent proliferations. Identities = 539/560 (96 %), 6 gaps (1 %)); and using the LSU Conidia aseptate, occasionally 1-septate, pale olivaceous sequence the ex-type strain of Exophiala brunnea CBS 587.66 brown, smooth- and thin-walled, ellipsoidal to reniform, 4–7 × (GenBank MH870554; Identities = 868/876 (99 %), 1 gap 2–4 μm, sometimes with a truncate base, solitary. Budding cells (0 %)). The ITS-LSU-BenA phylogenetic tree corroborated the scarce, ellipsoidal, ovoid or barrel-shaped, 7–11 × 3–4 μm, in placement of our isolate as a new species of Exophiala, being chains up to 5 elements. Chlamydospores scarce, olivaceous, located phylogenetically close to E. brunnea. Exophiala brunnea globose, 5–15 μm diam. is easily distinguished from E. frigidotolerans by the production Culture characteristics — Colonies on potato dextrose agar of 2-celled conidia (mostly 1-celled in E. frigidotolerans) and (PDA) reaching 5–6 mm diam after 2 wk at 25 °C, slightly raised, absence of budding cells (formed in E. frigidotolerans). velvety, margins regular, brownish grey (M. 5E2; Kornerup &

Wanscher 1978), sporulation absent, exudate absent; reverse Exophiala psychrophila CBS 191.87T 93/0.96 brownish grey (M. 5E2), diffusible pigment absent. Colonies on Exophiala cancerae CBS 120420T oatmeal agar (OA) reaching 6–7 mm diam after 2 wk at 25 °C, 87/0.96 Exophiala opportunistica CBS 109811T 87/0.95 T morphologically similar to those on PDA, with sparse sporulation. Exophiala lacus CBS 117497 Exophiala salmonis CBS 157.67T 94/0.99 Colonies on malt extract agar (MEA) reaching 5–7 mm diam Exophiala equina CBS 119.23T after 2 wk at 25 °C, slightly raised, velvety, margins regular, olive Exophiala tremulae CBS 129355T 99/1 T brown (M. 4E4), sporulation absent, exudate absent; reverse 77/0.97 Exophiala radicis P2854 Exophiala aquamarina CBS 119918T olive brown (M. 4F3), diffusible pigment absent. Colonies on Exophiala pisciphila CBS 537.73T potato carrot agar (PCA) reaching 4–6 mm diam after 2 wk Exophiala frigidotolerans FMR 17078 at 25 °C, slightly raised, velvety, margins regular, olive brown Exophiala brunnea CBS 587.66T (M. 4E4), sparse sporulation, exudate absent; reverse brownish Exophiala mesophila CBS 402.95T Exophiala castellanii CBS 158.58T grey (M. 4F2), diffusible pigment absent. Colonies on PDA reach- Exophiala capensis CBS 128771T T ing 10–11 mm diam after 2 wk at 15 °C slightly raised velvety, 93/0.98 75/0.96 Exophiala jeanselmei CBS 507.90 94/0.99 T margins regular, brownish grey (M. 5E2), sporulation absent, 87/1 Exophiala polymorpha CBS 138920 T exudate absent; reverse brownish grey (M. 5E2), diffusible pig- Exophiala hongkongensis HKU32 Exophiala nishimurae CBS 101538T 97/0.99 ment absent. Minimum, optimal and maximum temperature of Exophiala xenobiotica CBS 115831 growth, 10 °C, 15 °C, and 25 °C, respectively. Exophiala italica MFLCC16-0245T Exophiala angulospora CBS 482.92T 97/0.99 T Typus. Ecuador, Guayaquil, isolated from soil, Nov. 1996, L. Zaror 98/0.99 Exophiala alcalophila CBS 520.82 (holotype CBS H-24326, cultures ex-type FMR 17078 = CBS 146539; ITS, Exophiala halophila CBS 121512T LSU and BenA sequences GenBank LR699566, LR699567 and LR699568, Cyphellophora laciniata CBS 190.61T MycoBank MB832466). Cyphellophora pauciseptata CBS 284.85T 0.04 Notes — Exophiala frigidotolerans was recovered from a soil Maximum likelihood tree obtained from the ITS-LSU-BenA alignment of sample collected in Guayaquil, Ecuador. The genus Exophiala our isolate and sequences retrieved from GenBank. The tree was built by pertains to a group of fungi known as ‘black yeasts’, because of using RAxML CIPRES (http://www.phylo.org/sub_sections/portal/) and the the production of yeast-like colonies and budding cells with dark, analysis of probability was run in MrBayes v. 3.2.1 (Ronquist et al. 2012). Bootstrap support values ≥ 70 % and Bayesian posterior probability values ≥ 0.95 are presented at the nodes. Fully supported branches (100 % BS / Colour illustrations. Guayaquil, Ecuador (image credit Doug Moyer). 1 PP) are thickened. Cyphellophora laciniata CBS 190.61 and Cyphellophora Colonies growing on different culture media (PCA, MEA, OA at 25 °C and pauciseptata CBS 284.85 were used as outgroup. The new species proposed PDA at 15 °C; upper pictures); conidiogenous cells, conidia, budding cells in this study is indicated in bold. T represents the ex-type strains of the taxa and inflated cells. Scale bars = 10 µm. employed in this analysis.

Ernesto Rodríguez-Andrade, José F. Cano-Lira & Alberto M. Stchigel, Mycology Unit, Medical School and IISPV, Universitat Rovira i Virgili (URV), Sant Llorenç 21, 43201 Reus, Tarragona, Spain; e-mail: [email protected], [email protected] & [email protected]