Penicillium submersum Torres-Garcia, Gene and Dania Garcia, 2022

Torres-Garcia, Daniel, Gene, Josepa & Garcia, Dania, 2022, New and interesting species of Penicillium (Eurotiomycetes, Aspergillaceae) in freshwater sediments from Spain, MycoKeys 86, pp. 103-145 : 103

Penicillium submersum Torres-Garcia, Gene and Dania Garcia sp. nov.

Figure 14

Etymology.

Referring to the submerged sediment sample where the fungus was isolated.

Type.

Spain, Catalonia, Montsant Natural Park, Siurana's Swamp , from sediments, Feb. 2018, E. Carvalho & J. Gené (holotype CBS H-24785, cultures ex-type CBS 148242 = FMR 17140 ) .

Subgeneric classification.

Subgenus Penicillium Penicillium , Penicillium section Robsamsonia , series Penicillium Urticicola .

Description.

Mycelium superficial and immersed composed of septate, smooth-walled, hyaline hyphae, 2-2.5 μm wide. Conidiophores mostly terverticillate, in minor proportion biverticillate and quarterverticillate; stipes smooth-walled, 29-142 × 1.5-2.5 μm; metulae divergent, mostly 2, occasionally 3 per stipe/branch, 5.5-7.5 × 1.5-4 μm; phialides 2-5 per metula, ampulliform, 4-5.5 × 1.5-2.5 μm; conidia smooth-walled, ellipsoidal, 3-3.5 × 2-2.5 μm.

Culture characteristics (7 d at 25 °C).

Colonies on CYA, 34-37 mm diam., elevated, with some radially furrow, floccose, light yellow (4A5) and yellowish white (4A2) towards periphery, margins entire, sporulation sparse, conidial masses grayish green (28C4); reverse golden brown (5D7) and orange (5A6) at periphery; soluble pigment absent. On MEA, 28-29 mm diam., slightly elevated, floccose, white (1A1) to light yellow (4A5) at periphery, margins entire, sporulation sparse, conidial masses grayish green (27C3); reverse light yellow (4A5); soluble pigment absent. On YES, 33-36 mm diam., slightly elevated at center, radially sulcate, velvety, light brown (6D4) and white (1A1) towards periphery, margins slightly lobate, sporulation sparse, conidial masses grayish green (28C3); reverse grayish orange (5B5); soluble pigment absent. On OA, 18-20 mm diam., elevated at center, fasciculate, yellowish white (4A2) and pale gray towards periphery, margins low and entire, sporulation abundant, conidial masses grayish green (28B3); reverse grayish yellow (4C5); soluble pigment absent. On DG18, 11-13 mm diam., elevated, floccose, white (1A1) at center, pale yellow (4A3) and grayish yellow (4C3) towards periphery, margins entire, sporulation abundant, conidial masses grayish green (27C3); reverse light yellow (4A5) and yellowish white (2A2) at periphery; soluble pigment absent. On CREA, 15-19 mm diam., flattened, floccose, white (1A1) and pale yellow (3A3), margins low and irregular, sporulation sparse, conidial masses grayish green (28B3-C3); reverse white (1A1) and pale yellow (3A3); soluble pigment absent, acid production strong.

Colony diameter on CYA after 7d (mm).

5 °C no growth, 15 °C 20-21, 20 °C 25-26, 30 °C 28-30, 35 °C 17-16, 37 °C 9-11, 40 °C no growth.

Distribution.

Spain.

Notes.

Species in section Robsamsonia were characterized by restricted to moderately fast growth rate on CYA at 25 °C (15-32 mm diam in 7 d) and lack or slow of growth on CYA at 30 °C (up to 19 mm diam) ( Houbraken et al. 2016; Houbraken et al. 2020). However, the novel species showed faster growth rates on CYA at both temperatures (i.e., 34-37 mm and 28-30 mm diam., respectively). Penicillium submersum shares morphological features with the other two species ( P. griseofulvum and P. dipodomycola ) of the series Urticicola where it is classified (Fig. 2 ), which consisted in having bi-, ter, or quarterverticillate, divergent, smooth-walled conidiophores and short phialides (up to 7 µm) ( Houbraken et al. 2020). However, P. submersum shows the shortest phialides within the group (4-5.5 vs. 5-7 µm). In addition, our species has strong acid production on CREA, in contrast to the lack of acid production of P. griseofulvum and P. dipodomycola in the same medium ( Houbraken et al. 2016, 2020); and colony reverse on CYA and YES in P. submersum is golden brown to orange and grayish orange, respectively, while in P. griseofulvum and P. dipodomycola it is beige brown to dark brown in both culture media ( Houbraken et al. 2020). Furthermore, P. griseofulvum differs from P. submersum in its gray colony color, especially on CYA, which is in shades of yellow in our species.

Figures

Figure 2. Phylogenetic tree of Penicillium section Robsamsonia based on ML analysis obtained by RAxML inferred from the combined tub 2, cmdA, ITS, and rpb 2 loci. Branch lengths are proportional to phylogenetic distance. Bootstrap support values / Bayesian posterior probability scores above 70 % / 0.95 are indicated on the nodes. Bold branches indicate bs / pp values 100 / 1. The tree is rooted to P. paradoxum CBS 527.65 and P. malodoratum CBS 490.65. The name in red is the new species described in this study. T = Ex-type strain.

Figure 14. Morphological characters of Penicillium submersum sp. nov. (ex-type FMR 17140). A colonies from left to right (top row) CYA, MEA, YES, and OA; (bottom row) CYA reverse, MEA reverse, DG 18, and CREA B-F conidiophores on MEA G conidia. Scale Bars: 25 μm (B), 10 μm (C-G).