Pseudohumicola debertoldii Sastoque, Cano & Stchigel 2025, nom. nov.
Year: 2025
Type: other
Abstract: Pseudohumicola debertoldii Sastoque, Cano & Stchigel, nom. nov. MycoBank MB 853457. Fig. 8. Replaced synonym: Humicola lutea De Bert., Canad. J. Bot. 54: 2759. 1976, non Pseudohumicola lutea T.O. Condé et al. 2023 Etymology: In honour of Marco de Bertoldi, an Italian mycologist who also isolated this fungus. Typus: Italy, Sardinia, Sassari, soil from Quercus sp. forest, 1969, coll. and isol. M. de Bertoldi (lectotype designated here CBS H-25748, MBT 10026333, culture ex-type CBS 460.76 = FMR 20616). On potato carrot agar after 2 wk at 25 °C: Mycelium abundant, composed of hyaline, septate, branched, smooth-and thin-walled, 1–3 μm wide hyphae. Conidiophores absent. Conidiogenous cells integrated to the hyphae. Conidia mostly holoblastic, mostly unicellular, rarely 1-septate, solitary or in clusters, sessile or on short conical denticles or on short side branches, smooth- and thin-walled at first, becoming verruculose and thick-wall with the age, occasionally intercalary (holothallic) (Fig. 8E), sub-hyaline to brown, globose, subglobose, oblate, ellipsoid, obovoid, piriform, ovoid, fusiform or cylindric, (4–)7–11(–13) × (4–)7–12(–13) µm, mostly truncated at one end, or at both ends (if intercalary), secession rhexolytic (Fig. 8E). Acremonium-like synasexual morph present; conidiophores reduced to a conidiogenous cell; conidiogenous cell phialidic, arising on (discrete) or integrated to (adelophialides) the hyphae, hyaline, simple or 1-branched, flask-shaped (monophialides) or v-shaped (polyphialides) (Fig. 8F), 3–12 × 1–3 µm, mostly ventricose at the base and with a long neck that tapers progressively towards the apex; conidia enteroblastic, hyaline, formed basipetally in chains, unicellular, obovoid, 2–4 × 1–2 µm, truncated at the base and rounded at the apex (Fig. 8F). Culture characteristics (after 7 d at 25 ° C): Colonies on PCA 28–30 mm diam., flat and circular; margins entire and regular, brown (5F3) at the centre with radiated stripes showing sparse white (5A1) aerial mycelium at the centre; soluble pigment absent; reverse greyish brown (5E3) at the centre, with radiated dark brown (5F3) stripes and margins uncoloured. Colonies on OA 32–33 mm diam., flat, circular, and expansive; margins filamentous and regular; surface uncoloured, with a floccose white (4A1) aerial mycelium at the centre; soluble pigment absent; reverse uncoloured, cream (4B3) at the centre. Colonies on CMA 25–27 mm diam., flat, circular, and expansive; margins entire and regular; surface sepia (4F4), with a scarce white (5A1) floccose mycelium at the centre, and greyish green (30E5) superficial spots, margins uncoloured; soluble pigment absent; reverse dark green (30F5) at the centre. Colonies on MEA 27–28 mm diam., flat and circular; margins entire and regular; surface dark brown (5E4) with a white (5A1) floccose mycelium at the centre, and margins cream (4B3); soluble pigment absent; reverse similar than the surface. Culture iconography after 2 wk of incubation on PCA, OA, CMA and MEA (Fig. 8A–D, respectively). Minimum, optimum and maximum temperature of growth on PDA after 7 d: 5 °C, 30 °C and 40 °C, respectively. Notes: Humicola lutea CBS 460.76 was placed in the same fully supported clade as P. lutea COAD 3127, being consequently transferred to the genus Pseudohumicola as P. debertoldii (Fig. 1). Pseudohumicola debertoldii differs from P. lutea by the production of unicellular, rarely 1-septate conidia, smooth- and thin-walled at first, becoming verruculose and thick-wall with the age, with intercalary (holothallic) conidia, (4–)7–11(–13) × (4–)7–12(–13) µm and the production of an acremonium-like synasexual morph, in contrast to P. lutea, which produces lateral and terminal, single-cell, thick- but smooth-walled conidia, (7.5–)10.8–11.8(–14.5) × (7.2–)10.4– 11.2(–12) μm and lacking an acremonium-like synasexual morph (Oliveira et al. 2023).
Authors: Sastoque, A. P., Cano-Lira, J. F., Stchigel, A. M.
Institution: Universitat Rovira i Virgili
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7081149722
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