Penicillium subluteum , Y. B. Zhou & Houbraken, 2025

Zhou, Ya Bin, Meijer, Eelco F. J., Engel, Tobias G. P., Wang, Qi Ming, Feng, Zi Xuan, Hagen, Ferry, Meijer, Martin, Kraak, Bart, Meis, Jacques F. & Houbraken, Jos, 2025, Penicillium and Talaromyces diversity in cystic fibrosis patient sample and the description of a new species, Penicillium subluteum sp. nov. (Eurotiales, Aspergillaceae), MycoKeys 125, pp. 263-278 : 263-278

Penicillium subluteum, Y. B. Zhou & Houbraken sp. nov.

Fig. 3

Etymology.

Name refers to its pale yellow reverse on CYA and DG 18.

Diagnosis.

Colonies grow rapidly on all tested media except CREA and exhibit a pale yellow reverse on CYA (3 A 3) and DG 18 (1 A 3). Conidiophores are biverticillate and conidia are produced in long, distorted chains and are smooth and broadly ellipsoidal.

Classification.

Penicillium subgen. Aspergilloides sect. Citrina ser. Paxillorum

Typus.

The Netherlands • Nijmegen , human sputum; holotype: CBS H-23699 ; culture ex – type: CBS 144762 = DTO 200-G 7 = CF 0895 .

ITS barcode.

PV 645068 (alternative markers: BenA = PV 646810; CaM = PV 646812; RPB 2 = PV 646822).

Colony diam.

(25 ° C, 7 d, in mm): CREA 12–17; CYA 30–34; CYA 30 ° C 17–20; CYA 37 ° C no growth; CYA 40 ° C no growth; CYAS 30–35; DG 18 29–32; MEA 28–31; OA 20–28; YES 35–38.

Colony characters.

(25 ° C, 7 d): CYA: Colonies slightly sunken in center, radial sulcate, margin nearly entire; sporulation dense; mycelium white; colony texture velvety; exudates present as hyaline droplets; soluble pigments absent; conidia en masse grayish green (26 D 5) to dull green (26 E 4); reverse pale yellow (3 A 3). CYAS: Colonies slightly sunken in center, radial sulcate, margin entire; sporulation dense; mycelium white; colony texture velvety; exudates present as hyaline droplets; soluble pigments absent; conidia en masse grayish green (26 D 5); reverse pale yellow (3 A 3). MEA: Colonies low, radial sulcate, margin entire; sporulation dense; mycelium white; colony texture velvety; exudates present as hyaline droplets; soluble pigments absent; conidia en masse grayish green (27 E 5); reverse grayish yellow (4 B 6). YES: Colonies sunken in center, radial sulcate, margin nearly entire; sporulation dense; mycelium white; colony texture velvety; exudates absent; soluble pigments absent conidia en masse grayish green (26 D 5) to dull green (26 E 4); reverse pale yellow (3 A 3). DG 18: Colonies slightly raised in center, radial sulcate, margin entire; sporulation dense; mycelium white; colony texture velvety; exudates absent; soluble pigments absent; conidia en masse grayish green (26 D 6); exudates absent; soluble pigments absent; reverse pale yellow (1 A 3). OA: Colonies plane, margin entire; mycelium white; colony texture velvety; sporulation dense; conidia en masse grayish green (27 D 5). exudates present as hyaline droplets; soluble pigments absent. CREA: poor growth, acid production absent, base formation absent.

Micromorphology.

Conidiophores biverticillate; stipes smooth-walled or finely roughened, 130–325 × 2–4 µm; metulae cylindrical, 9.5–13 × 2.5–4.5 µm; phialides flask shaped, 3–8 per metulae, 8.5–12.5 × 2.5–3.5 µm; conidia in long, distorted chains, smooth, broadly ellipsoidal, 3–4 × 2.5–3.5 µm.

Additional specimens examined.

Australia • Queensland, Barrine, near lake Cratez , isolated from soil, CBS 127361 = DTO 030–A 6 = IBT 29070 ; China • Tibet, Zunyi Area, Meti Country , isolated from soil, MT 3 F-102 .

Note.

This species is both morphologically and phylogenetically related to P. paxilli . However, P. subluteum has a pale yellow reverse on CYA and DG 18, in contrast to the pale reverse observed in P. paxilli ( Houbraken et al. 2011) . Pairwise nucleotide differences between the type strains of the two species include 10 nucleotides in ITS, 19 bp in BenA, 26 bp in CaM, and 30 bp in RPB 2.

Figures

Figure 3. Penicillium subluteum CBS 144762 T. A. Colony morphology of P. subluteum CBS 144762 incubated at 25 ° C for 7 d: top row left to right, obverse CYA, obverse YES, obverse DG 18 and obverse MEA; bottom row left to right, reverse CYA, reverse YES, reverse DG 18 and CREA; B. Detail of colony on MEA after 7 d incubation; C – F. Conidiophores; G. Conidia. Scale bars: 10 μm.