Psychromyces glacialis
Psychromyces glacialis L. Perini & Zalar, in L. Perini, et al., International Journal of Systematic and Evolutionary Microbiology 71 (2, no. 4655): 15 (2021)
Etymology: Psychromyces glacialis (gla.ci.a’lis. L. masc. adj. glacialis icy, frozen).
Diagnosis: Streak cultures at 15 °C after 14 days on PDA agar mucoid, orange white, filamentous, 2–6 mm diameter, margin composed of fine filaments immersed into the medium. Synnemata-like dense bundles of hyphae form on initial inoculation points. Yeast colonies visible after 3 weeks, attain 2 mm diameter after 7 weeks on PDA and MEA, 0.5 mm on SNA, pastel red, convex and mat. After 3 months on PDA at 15 °C, the filamentous colonies reach up to 40 mm diameter, become pale red to pastel red, mat. Mycelium in some strains without clamps (EXF-13111), 1.5–2.0 μm wide, or with clamps, 2–4 μm wide, branched. After 14 days of incubation, numerous teliospores are produced intercalary. Teliospores oblong, (5.5–) 8×10 (–13) (mean; min-max: 5.5–13) μm. Budding occurring in yeast colonies polar or occasionally multilateral, sessile or on short or long denticles, and with sympodial proliferation. Individual yeast cells on MEA: 8.5±2 (mean±SD; min-max: 5.5–11)×(2.5) 3.5±0.5 (4.5) μm, on PDA: 7.5±3 (mean±SD; min-max: 5–12)×3.5±0.5 (mean±SD; min-max: 3–4) μm. Dalmau plate culture on CMA agar, 7 weeks of incubation: numerous teliospores on densely septated mycelium. Assimilated compounds: α-d- glucose, sucrose, raffinose, trehalose, maltose, melezitose, cellobiose (sometimes weak), nitrate, nitrite and cadaverine. Variable: salicin, l-sorbose, d-xylose, l-arabinose, d-glucosamine and l-lysine. Not assimilated compounds: melibiose, d-galactose, starch, d-arabinose, d-ribose and glycerol. Additional data on C source assimilation obtained by Biology YT plates only are given. Does not grow in the presence of 10%, 15 % NaCl, 50 % glucose. Growth at 5, 10, 15 °C is positive; no growth evident at 20 °C. Fermentation abilities absent.
Index Fungorum Number: IF 834190.
Figure 1. Phylogenetic tree based on alignment of the SSU, LSU, 5.8S rDNA, TEF, CYTB, RPB1 and RPB2 estimated by maximum-likelihood and Bayesian analyses. The tree includes representatives of Psychromyces glacialis gen. nov., sp. nov., Camptobasidium arcticum sp. nov., C. gelus and representative species of genera of Microbotryomycetes. In the maximum-likelihood estimation, the best model of nucleotide substitution was estimated with jModelTest, other parameters (alpha parameter of the gamma distribution of substitution rate categories, proportion of invariable sites) were estimated within PhyML. aLRT as Chi2-based support was used for calculation of branch supports. In estimation by MrBayes, a total 10 million generations were calculated and the first 25 % were discarded before the shown consensus tree was calculated from trees sampled every 100 generations. Posterior probabilities higher than 0.9 (in green) and maximum-likelihood bootstrap value from 1000 bootstrap replicates larger than 70 % (in blue) are shown near the nodes.
Figure 2. Morphology of Psychromyces glacialis. (a, b) cultures of Psychromyces glacialis EXF-13111 at 15 °C: (a) PDA, dimorphic culture after 3 weeks of incubation, (b) PDA, yeast culture grown from single yeast colony after 1 month of incubation, (c) PDA, filamentous culture grown from the margin of filamentous colony after 1 month of incubation; (d–g) teliospores grown on (d) CMA, Dalmau plate after 1 month of incubation in 60 % lactic acid, (e) PDA, margin of filamentous colony after 10 weeks of incubation in 60 % lactic acid, (f) PDA, yeast part of colony after 3 weeks of incubation, mounted in water, (g) PDA, filamentous colony after 3 weeks, coloured with calcofluor white; (h–n) yeast cells, (h, i, m, n) PDA, from dimorphic culture after 3 weeks of incubation, (h–i) mounted in water, (m–n) stained with calcofluor white (l) PDA, dimorphic culture in water after 1 month of growth on PDA, rudimentary pseudohyphae; (i–m) PDA, budding cells on short or long denticles, (n) PDA, yeast cells with inclusions.
Reference:
Perini, L; Andrejašič, K; Gostinčar, C; Gunde-Cimerman, N; Zalar, P. 2021. Greenland and Svalbard glaciers host unknown basidiomycetes: the yeast Camptobasidium arcticum sp. nov. and the dimorphic Psychromyces glacialis gen. and sp. nov. International Journal of Systematic and Evolutionary Microbiology. 71(2, no. 4655):1-17
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